lcd panel edge connector repair factory
2. There are no instructions for removing the old, black adhesive from around the edge of the old case (nor the much needed instructions for reinstalling the new adhesive without damaging it or compromising the purpose of replacing this adhesive). This info is also missing from the adhesive replacement page for the iPhone 11.
I was able to patiently work my way through both of these issues and complete the repair on an iPhone 11. Covering these issues as additional steps of the repair guide would be very helpful for future iFixers.
Done! Boy, it took me 1.5 but done. Anyway don"t forget guys it"s quality that counts so don"t hurry up, take your time & get light (lots of light above you). Get a coke and it will work it. I reassembled everything, turned it on and home button working yeah. Ouch, my screen was no more sensitive. I killed the digitizer cable. Lucky me I had another broken iPhone which i took the LCD and put it on my phone. (about 1.5 again to reassemble everything back)
HP recommends that you only order parts from an authorized HP repair parts dealer. Parts ordered from third-party companies might not perform as expected and might cause additional
Connectors are a prevalent part of almost any electronic project. Understanding the available connectors and the specification considerations that one would need to keep in mind is important throughout the design process. You don’t want to get near the end of the project and find that you need to add one and need to adjust the project to accommodate as this can end up being costly in both time and money aspects.
When selecting a connector for your project, there are a few considerations that would need to be made when specifying the requirements for your connector. Some of the more common questions would be:
In many cases, knowing the number of contacts required by the connector is known. However, sometimes, other needs for the overall application and the availability of the items can end up affecting the resulting selected item’s specifications.
Further consideration would also need to be given to the power that the connector will need to handle as this will affect the option that is selected. As the power handling capacity of a connector continues to increase, one may find that the total number of contacts for any package/shell size will go down. This is caused by needing more room for larger wire gauge and/or higher voltages. Some manufacturers have managed to increase the voltage ratings by adding more isolation between the contacts and the total “distance” that the electrical arc would need to travel from one contact to the next. Also, there are some connectors that have a grounding contact built into the rest of the contacts. They are longer than the others in the connector and are used to reduce/eliminate arcing between the two mating/un-mating connectors.
Another consideration for your project would be how you would like or need each connector to mount. Types of mounting can include the below, to name a few, and example links.
PCB pin through hole - Where the terminating leads of the connector are used to mount/fasten the item to the circuit board through holes placed in the board.
PCB surface mounting - Where the terminating leads of the connector are used to mount/fasten the item to the circuit board is it placed on to contact pad on the surface of the board.
Panel mounting - Where a hole has been made in a surface or panel and the connector is placed either through or against the hole. Fastening can vary from a thread and nut to the connector held in place as a result of it being mounted to a board behind the panel.
Board/card edge/cutout mounting - For card edge the terminations are near an edge of a board, in many cases the connector is modified in order to take advantage of it being on the edge. For board cutout, they are similar as they are near the edge of the board. However, a portion of the board has been cutout in order for the connector to have a lower profile. In both cases the lower overall board profile that can result is what is being utilized. Additionally, it can also be done because no other space is available on the board or because of other design needs.
Through board - Similar to cutout mounting. However, these are not typically seen next to the edge of the board. They are also similar to panel mounting connectors as they mount through a hole cut in the board. Some terminate through holes in the board and solder on the same side as the connector mates while others surface mount to the side of the board the connectors mount from (opposite from the side the connector mates). The below would be examples of this item type:
The terms mounting and termination have been known to be used interchangeably, however one would need to keep in mind that is not always the case and that there can be a distinction. Mounting indicates how the overall project and the connector as a whole interface/fasten/attach. Termination indicates how the electrical connections are being made. Through-hole mounting and surface mounting in most cases indicate items that would mount and terminate in a particular way (see Termination Method below for more). As an example of a mounting, mating, and termination combination that could happen would be:
Soldering/solder termination - For connectors, this termination method should work fine for a wide range of applications. However, if the application is going in high temperature areas, one may need to consider more mechanical means of termination. Soldering can be for wire termination as well as for board terminated connections. As such, this type of termination includes a variety of ways an item can be soldered. Through hole soldering and surface mount, as indicated above, describes a mounting and termination type.
Through hole soldering - On the termination side of the connector there are leads designed to go through holes in a board that have been prepared and usually have copper pads on the other surface of the board from the through-hole connector. Once placed they are soldered in place.
Surface mount termination - The leads of the item and the mounting pads are on the same side of the PCB. The item is either placed by hand and soldered in place or a re-flow or wave-soldering methods are used to solder it in place. Note that some board/card edge connector types are also surface mount types.
Crimping - This type of termination has been known to be quite rugged and reliable and would be used or terminating wires. However, that is predicated on the quality of the crimp itself and correct installation in to the contact housing. To achieve a quality crimp and overall connection, one would need to be sure that the correct contacts for the housing are used as well as the correct crimping tools. For these contacts, tooling is an important step. If the end quality is not a concern, then it may be possible that other tools that you may have already or lower cost options could be utilized. However, if it is or could be, then the tools recommended by the manufacturer would need to be used as well as the appropriate preparation steps for the wire and any quality of crimp data that the manufacturer provides for post crimp inspection (note - not all need to be checked, just a sample for verification). If the tooling and correct procedures are not used and a failure does occur in the connection, most if not all manufacturers of such connectors will not provide support or warranty.
Terminating to these types typically only requires the wire to be stripped, then either just pushed into the connector or a lever be actuated to an unlocked state and the wire inserted and the lever moved to a locked state.
Figure 5: This board mounting connector has stripped wires terminated to it by pushing it in to the lower opening. A tool can be used in this case to release the wire if needed.
Screw terminals - These are used in a variety of connector types and can be used in a few different ways. The following items are examples of the different types of screw termination terminals:
These connectors are not necessarily used in a product that is going to be put in to large scale production. They are used in High frequency end products and low production count prototypes
If the application is in a fairly sedate environment and it is not expected to see anything extreme, then nearly any connector would work for the specific needs defined. However as one makes projects for more hostile environments - things like vibration, kinetic shock, shielding, environmental ingress, oils, solvents, or any variety of chemicals and corrosion that the connector in question may be exposed to - one would need to be kept these in mind during the selection process.
For connections that are passing into/out of the enclosure, there can be a fair number of possible choices that could be selected for any particular type of connector.
Review the specifications for the connectors that are being considered to see if they were tested and rated for the level of shock and vibration that you would be expecting for the project to experience.
For connectors where shielding is employed, one would need to make considerations on if only a specific part would have the shielding or if the (in the case of cables) whole path would need to have a unified shield. Take Ethernet cables for example. If the environment is fairly tame, then some basic Ethernet cabling and 8 position modular connectors could be used. However, as the ambient magnetic noise increases, the usage of shielded modular connectors and Ethernet cable would need to be considered/implemented.
Ingress protection ratings indicate how well an item can prevent solids/dust and moisture/water from entering into an area that is being protected. If this is a concern it should be considered throughout the process of selecting a connector. It would be used to filter out all of the other options that don’t match the ingress requirements.
When selecting a connector, you will need to pick an option that would be able to handle the expected maximum current that could end up being applied to the connector.
When selecting a connector, you would need to pick an option that would be able to handle the expected maximum voltage that could end up being applied to the connector.
Luckily, it’s possible to repair or remanufacture boards to make them like new again. This does one of two things. Either the board in question can be returned to its original device, making it function again. Or, it can be used in a completely different device, as a form of recycling if you will.
Of course, before any board can be repaired or reconditioned, engineers need to discern and understand why it failed in the first place. You can’t very well fix a problem if you don’t know what went wrong, can you?
Boards are often produced in layers, which include various levels of conductive and non-conductive sheets. They can be one-sided with a single copper layer, two-sided with a double copper layer on both sides of a substrate layer, or multi-layer with differing layers of copper and substrate. It is worth mentioning that multi-layer boards provide a variety of benefits like an increased component density, however they are much harder to analyze, repair and modify.
It’s important to understand that circuit board repair parts and practices often consist of the same materials and components used to build the hardware in the first place. There are very few substitutes or alternatives, especially when talking about reliable and conductive materials. This highlights the need to find a proper, professional repair team with the right assets and connections.
As technology has advanced over the years, so has the design and development of circuit boards allowing for smaller, more complex components, and thinner, less bulky boards. This makes the circuit board repair process particularly tricky because there are so many different types of varying sizes and design. You can’t go to just anyone to have a printed circuit board repair, modified or re-manufactured. It is crucial that you go to an authorized party who has both the experience and necessary gear to make it happen.
So long as complete failure is not the scenario—the board fell upon the ground and shattered or broke completely—physical damage can be remedied through the remanufacturing process. Generally, this involves melting down the damage sections of the board or repairing through disassembly and reassembly. Due to the nature of most physical damage, it’s highly unlikely that this can be done as a DIY project by those without experience with printed circuit board repair. The repair of physical damage should only be done by a trained and experienced professional. In most cases, it calls for remodeling of the board, resoldering of components, and the reballing of conductive traces.
You may be asking, how to fix a printed circuit board when a component fails? Again, the repair and remanufacturing process for faulty components is best left to professionals. There are voltage tools and various devices that can be used to test the conductivity of a board’s circuit. They can also be used to discern if there’s electricity flowing to a component, or if an element of the board has failed entirely. A lot of times, by just opening up the device you can see components that have failed. Their outer shell may seem burnt, cracked or broken, or the component is completely detached from the board and loose.
To repair faulty or damage trace pathways, you simply need to resolder or reball the board with the necessary material. This reconnects the broken circuit and allows electricity to flow freely throughout the board.
You’ll know as soon as you have a faulty or poor circuit board because your device will continue to fail time and time again, even after a repair or service session. The best solution for a shoddy circuit board is to replace it completely, by visiting an official or licensed repair center.
The easiest way to identify a poorly designed board is the number of failures or problems after extended use. Barring significant physical or electrical damage to the device, if you take the board to be repaired or analyzed somewhere and there are a handful of issues, there’s likely something wrong with the way the board was constructed. In some cases, this simply means the original manufacturer used cheap or unreliable components, but the board itself is fine.
All professional repair teams have a power or voltage meter that can be used to identify electrical issues with a board and its components. Voltage tools are really the only way to diagnose a problem outside of visible damage to a component. As for repair, the process is best left to professionals but generally involves reseating or replacing components.
There are several ways in which a printed circuit board can be repaired or serviced, with varying degrees of skill required. For the most part, however, anything to do with the internals of an electronic or device calls for knowledge of engineering and mechanics, and basic electrical circuits. For some of the larger devices on the market, you could seriously injure or even fatally wound yourself if you don’t know what you’re doing.
For physical or visible damage to a board, base board repair is necessary. This may include melting down similar materials to reshape or modify the board, or can sometimes even call for complete disassembly.
For conductor and component repair, knowledge and skill of soldering, desoldering, BGA rework and pinpoint accuracy may all be necessary. If you’ve ever worked with or held a soldering iron before, it’s not so easy to retain a steady hand and spread the material evenly. You will want extensive experience with a soldering and desoldering iron, just to be sure the components and parts are seated properly to the board.
Of course, there are a variety of IPC and ICO standards necessary to follow for professionals, to ensure electronics and components are constructed and repaired using proper protocols. If you are not aware or don’t know enough about these standards, you may find yourself in hot water later.
An EMS, if you don’t know, is often a circuit board repair company that designs, manufactures, tests, distributes, and repairs electronic components and internal assemblies. They commonly service components and devices for OEMs or original equipment manufacturers. An OEM is the company that originally designed and owns the product in question.
As is to be expected, most repairs require the same materials—or improved materials—used in the official design of a board. It may call for copper or silver to be reseated to repair trace pathways. PCB substrates are often comprised of fiberglass or an epoxy resin with copper foil bonded to the conductive layer. They may also be comprised of reinforced phenolic resin, a more paper-like material that’s thinner than fiberglass.
The best service and repair teams can reassemble or fix a damaged board near enough to its original condition that there’s almost no difference in a previous version and the upgraded one. Certainly, this requires a great deal of finesse and experience that you won’t find outside of an experienced and professional setting.
An important part of researching and hiring a professional repair service is making sure they have the proper PCB repair materials and tools available to get the job done. Some service repair teams don’t have everything on property or on-site, which can balloon the time it takes to repair or reassemble parts. They have to wait to receive the requisite materials or tools.
It’s no secret that a lot of the materials used are not environmentally-friendly or conducive to safety. We’re a long ways off, but there are scientists and bleeding edge teams working on bio-degradeable PCBs that will break down naturally after being discarded.
For PCB repair and remanufacturing and industrial PCB repair service options you can’t do any better than EMSG Inc. (Electronic Manufacturing Services Group). We are well suited to handle board level and complete box build assemblies, including any custom packaging you may have created or utilized.
We have a highly advanced facilitywith the latest manufacturing and repair technologies, which allow us to be incredibly precise, yet efficient in our duties. This, coupled with our incredibly experienced personnel, modern equipment and great management team means we can be swift and reliable and get any repairs or development done within the schedule of your choosing.
We are highly confident that EMSG will play an integral role in the design and development of your product. The information presented here is merely scratching the surface of what’s necessary to conduct and perform a professional-grade repair and remanufacturing service. You can rest assured, we have the skills, experience and tools to get you to market as soon as possible.
If you’re interested in our manufacturing or repair services, please fill out this contact form and allow us to reach out to you. You can also give us a call, anytime, to speak to a company representative.
If the display problem is still existing in the BIOS configuration, which means the screen hardware may be defective, and we recommend you visit the ASUS authorized repair center to test your laptop.
The screen color temperature might be a little bit different for each panel even if the manufacturing process is the same, so it’s normal. ASUS makes sure the manufactured products to meet the specification, so please feel free to use it.
Glass substrate with ITO electrodes. The shapes of these electrodes will determine the shapes that will appear when the LCD is switched ON. Vertical ridges etched on the surface are smooth.
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.
Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, often made of Indium-Tin oxide (ITO) and two polarizing filters (parallel and perpendicular polarizers), the axes of transmission of which are (in most of the cases) perpendicular to each other. Without the liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer. Before an electric field is applied, the orientation of the liquid-crystal molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic (TN) device, the surface alignment directions at the two electrodes are perpendicular to each other, and so the molecules arrange themselves in a helical structure, or twist. This induces the rotation of the polarization of the incident light, and the device appears gray. If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, light can be allowed to pass through in varying amounts thus constituting different levels of gray.
The chemical formula of the liquid crystals used in LCDs may vary. Formulas may be patented.Sharp Corporation. The patent that covered that specific mixture expired.
Most color LCD systems use the same technique, with color filters used to generate red, green, and blue subpixels. The LCD color filters are made with a photolithography process on large glass sheets that are later glued with other glass sheets containing a TFT array, spacers and liquid crystal, creating several color LCDs that are then cut from one another and laminated with polarizer sheets. Red, green, blue and black photoresists (resists) are used. All resists contain a finely ground powdered pigment, with particles being just 40 nanometers across. The black resist is the first to be applied; this will create a black grid (known in the industry as a black matrix) that will separate red, green and blue subpixels from one another, increasing contrast ratios and preventing light from leaking from one subpixel onto other surrounding subpixels.Super-twisted nematic LCD, where the variable twist between tighter-spaced plates causes a varying double refraction birefringence, thus changing the hue.
LCD in a Texas Instruments calculator with top polarizer removed from device and placed on top, such that the top and bottom polarizers are perpendicular. As a result, the colors are inverted.
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:
Until Gen 8, manufacturers would not agree on a single mother glass size and as a result, different manufacturers would use slightly different glass sizes for the same generation. Some manufacturers have adopted Gen 8.6 mother glass sheets which are only slightly larger than Gen 8.5, allowing for more 50 and 58 inch LCDs to be made per mother glass, specially 58 inch LCDs, in which case 6 can be produced on a Gen 8.6 mother glass vs only 3 on a Gen 8.5 mother glass, significantly reducing waste.AGC Inc., Corning Inc., and Nippon Electric Glass.
In 1922, Georges Friedel described the structure and properties of liquid crystals and classified them in three types (nematics, smectics and cholesterics). In 1927, Vsevolod Frederiks devised the electrically switched light valve, called the Fréedericksz transition, the essential effect of all LCD technology. In 1936, the Marconi Wireless Telegraph company patented the first practical application of the technology, "The Liquid Crystal Light Valve". In 1962, the first major English language publication Molecular Structure and Properties of Liquid Crystals was published by Dr. George W. Gray.RCA found that liquid crystals had some interesting electro-optic characteristics and he realized an electro-optical effect by generating stripe-patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electro-hydrodynamic instability forming what are now called "Williams domains" inside the liquid crystal.
In the late 1960s, pioneering work on liquid crystals was undertaken by the UK"s Royal Radar Establishment at Malvern, England. The team at RRE supported ongoing work by George William Gray and his team at the University of Hull who ultimately discovered the cyanobiphenyl liquid crystals, which had correct stability and temperature properties for application in LCDs.
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.
In 1972 North American Rockwell Microelectronics Corp introduced the use of DSM LCDs for calculators for marketing by Lloyds Electronics Inc, though these required an internal light source for illumination.Sharp Corporation followed with DSM LCDs for pocket-sized calculators in 1973Seiko and its first 6-digit TN-LCD quartz wristwatch, and Casio"s "Casiotron". Color LCDs based on Guest-Host interaction were invented by a team at RCA in 1968.TFT LCDs similar to the prototypes developed by a Westinghouse team in 1972 were patented in 1976 by a team at Sharp consisting of Fumiaki Funada, Masataka Matsuura, and Tomio Wada,
In 1983, researchers at Brown, Boveri & Cie (BBC) Research Center, Switzerland, invented the passive matrix-addressed LCDs. H. Amstutz et al. were listed as inventors in the corresponding patent applications filed in Switzerland on July 7, 1983, and October 28, 1983. Patents were granted in Switzerland CH 665491, Europe EP 0131216,
The first color LCD televisions were developed as handheld televisions in Japan. In 1980, Hattori Seiko"s R&D group began development on color LCD pocket televisions.Seiko Epson released the first LCD television, the Epson TV Watch, a wristwatch equipped with a small active-matrix LCD television.dot matrix TN-LCD in 1983.Citizen Watch,TFT LCD.computer monitors and LCD televisions.3LCD projection technology in the 1980s, and licensed it for use in projectors in 1988.compact, full-color LCD projector.
In 1990, under different titles, inventors conceived electro optical effects as alternatives to twisted nematic field effect LCDs (TN- and STN- LCDs). One approach was to use interdigital electrodes on one glass substrate only to produce an electric field essentially parallel to the glass substrates.Germany by Guenter Baur et al. and patented in various countries.Hitachi work out various practical details of the IPS technology to interconnect the thin-film transistor array as a matrix and to avoid undesirable stray fields in between pixels.
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,
In 2016, Panasonic developed IPS LCDs with a contrast ratio of 1,000,000:1, rivaling OLEDs. This technology was later put into mass production as dual layer, dual panel or LMCL (Light Modulating Cell Layer) LCDs. The technology uses 2 liquid crystal layers instead of one, and may be used along with a mini-LED backlight and quantum dot sheets.
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.
Monochrome LEDs: such as red, green, yellow or blue LEDs are used in the small passive monochrome LCDs typically used in clocks, watches and small appliances.
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).
The LCD backlight systems are made highly efficient by applying optical films such as prismatic structure (prism sheet) to gain the light into the desired viewer directions and reflective polarizing films that recycle the polarized light that was formerly absorbed by the first polarizer of the LCD (invented by Philips researchers Adrianus de Vaan and Paulus Schaareman),
A pink elastomeric connector mating an LCD panel to circuit board traces, shown next to a centimeter-scale ruler. The conductive and insulating layers in the black stripe are very small.
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.
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.
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.
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.
This pixel-layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone (range of viewing directions with good contrast and low color shift).
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.
Blue phase mode LCDs have been shown as engineering samples early in 2008, but they are not in mass-production. The physics of blue phase mode LCDs suggest that very short switching times (≈1 ms) can be achieved, so time sequential color control can possibly be realized and expensive color filters would be obsolete.
Some LCD panels have defective transistors, causing permanently lit or unlit pixels which are commonly referred to as stuck pixels or dead pixels respectively. Unlike integrated circuits (ICs), LCD panels with a few defective transistors are usually still usable. Manufacturers" policies for the acceptable number of defective pixels vary greatly. At one point, Samsung held a zero-tolerance policy for LCD monitors sold in Korea.ISO 13406-2 standard.
Dead pixel policies are often hotly debated between manufacturers and customers. To regulate the acceptability of defects and to protect the end user, ISO released the ISO 13406-2 standard,ISO 9241, specifically ISO-9241-302, 303, 305, 307:2008 pixel defects. However, not every LCD manufacturer conforms to the ISO standard and the ISO standard is quite often interpreted in different ways. LCD panels are more likely to have defects than most ICs due to their larger size. For example, a 300 mm SVGA LCD has 8 defects and a 150 mm wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the whole LCD panel would be a 0% yield. In recent years, quality control has been improved. An SVGA LCD panel with 4 defective pixels is usually considered defective and customers can request an exchange for a new one.
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.
In 2004, researchers at the University of Oxford demonstrated two new types of zero-power bistable LCDs based on Zenithal bistable techniques.e.g., BiNem technology, are based mainly on the surface properties and need specific weak anchoring materials.
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.
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.
Usually no refresh-rate flicker, because the LCD pixels hold their state between refreshes (which are usually done at 200 Hz or faster, regardless of the input refresh rate).
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.
LCDs can be made transparent and flexible, but they cannot emit light without a backlight like OLED and microLED, which are other technologies that can also be made flexible and transparent.
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.
Limited viewing angle in some older or cheaper monitors, causing color, saturation, contrast and brightness to vary with user position, even within the intended viewing angle. Special films can be used to increase the viewing angles of LCDs.
Uneven backlighting in some monitors (more common in IPS-types and older TNs), causing brightness distortion, especially toward the edges ("backlight bleed").
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.
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.
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".
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Heat, vibration and 20+ years of aging causes significant wear on the factory LCD connector. Spring terminals weaken, wires break and oxidation pits the surface of the terminals. Eventually the contacts become open and LCD operation becomes intermittent, or the LCD stops working entirely
Important: Pull the Input Cover off carefully as it is still attached to the Mainboard via the Touchpad Cable. You don"t need to disconnect this cable to do most repairs. You can just flip the Input Cover over. If you do want to disconnect it though, make sure to disconnect the Mainboard side using the finger loop over the orange label.
You should keep the Battery connector plugged in unless you need to replace the Battery, Mainboard, or Speakers. This connector is easy to accidentally damage, so it"s better to not handle it.