lcd panel backlight not working quotation

Ever had your TV showing nothing but a black screen even if the audio was working? Unfortunately, that’s a common issue with low/middle-end LCD/LED TVs these days… Even more frustrating, this issue often comes from a rather tiny and cheap component that can be easily replaced. Most common issues are:

The first step into repair is to find the root cause of the issue. As backlight failure is a very common issue, this is the first thing to test. To do so, the easiest way is to power on your screen, put a flashlight very close to it and check if you can see the image through. The image would be very dark, like turning the brightness of the screen very very low.

That implies disassembling the TV to access the backlight which is between the LCD screen in the front and the boards in the rear. In my case, with a Samsung F5000, I had to process as follows:

First we have to remove the back housing to reveal the boards (from left to right: main board, T-CON, power supply) and disconnect the LCD panel from the T-CON board.

Note: Older TVs have neon tubes for backlight, which is thicker and less exposed to this kind of failure. LED backlight is the most common thing these days, but do not mistake an LED TV with an OLED TV. The first one is a classic LCD panel with a LED backlight, whereas the second is an OLED panel that doesn’t need any backlight as it is integrated in each pixels (making the spare parts much more expensive by the way).

As we can see, the backlight system is made of 5 LED strips. First thing to do is look for burnt LEDs. Most LED backlight systems have strips set in series, meaning that if one of the them fails, all the system goes dark…

One LED like those ones typically needs between 2.5-3.6v input voltage to light up. By looking up this model online, I found out that the ones used on those strips need 3.6v; so as there are 9 LEDs per strip: 3.6 x 9 = 32.4v input voltage required to light a single strip. That’s the maximum voltage we do NOT want to exceed, otherwise LEDs could be damaged during testing.

So, I took 3 9v batteries that were laying in a drawer, put them in series to make a virtual 27v battery (3 x 9v). It’s less then the optimal 32.4v required but not that much lower, it might be able to light the strip a bit so we can identify which is not working. Here is a look at the set-up:

Now we simply have to test each strips individually to see if they light up or not. For each that doesn’t completly, it will mean it has at least one defective LED.

After repeating this operation on all strips, I found only 1 defective LED, the same we thought looked burnt when we first had a look at the backlight (3rd strip from the top, 6th LED from the left). For a better understanding at what a burnt LED looks like here are 2 pictures of a burnt one and an OK one. Mind the roasted color compared to the regular one.

For starters I’ll go with the third one, just to make sure there is no other issues with the TV, but afterwards it’s better to replace the LED with a new one, otherwise you might notice a darker spot on the image.

The cost to repair a TV screen can be significantly more than the cost of purchasing a new TV. For this reason, replacing or repairing a broken TV screen is not considered feasible.

Most TV or electronics repair companies do not offer TV screen repair, and many warranties do not cover the service. For example, BestBuy"s 90-day warranty does not list broken TV screen repair as one of the problems they cover.

Unless you are trying to fix a TV from the ’80s or earlier, cracked TV screen repair is not feasible; the entire display panel must be replaced instead. The cost of a replacement TV display panel is often more than the cost of buying a new TV, and that’s before labor and other service costs.

The cost of TV screen replacement is generally the same as or more than the cost of buying a new TV. Therefore, replacing a broken or malfunctioning TV screen is not considered a viable option. If the TV is under the manufacturer’s warranty, the manufacturer may replace the entire unit.

TV manufacturers do keep replacement TV screen panels on hand to support products under warranty in case the screen malfunctions, due to manufacturer defect.

If you still want to replace a damaged or malfunctioning TV screen, your best option is to find a used replacement panel or a broken TV of the same model on which the screen is still functional. You might find one on eBay, and you can hire a technician to change out the panel.

Whether your TV is LCD, LED, plasma screen, or 4K (Ultra HD), the cost to fix common problems ranges from $60 to $350, depending on the repair type and the TV brand.

The function of an inverter board in a TV is to power the backlight of the screen. The inverter board requires a few hundred volts of power. If the inverter board goes bad, it causes the TV to power on with sound but no picture.

If an older model LCD TV or projection TV powers on and has sound but no picture, this may be due to lamp burnout, which is both common and expected. In this case, replacing the bulb will fix the problem. An experienced technician should be able to replace the bulb quickly and easily.

TV backlight repair costs $100 to $120, including replacement parts and labor, at a repair shop. In-house repair costs are more due to trip fees. The price of backlight replacement parts averages around $2.50for each LED and between $20 and $25 for each CCFL strip.

A new inverter may be needed to power the LEDs, costing $7 to $75before labor, or an average of $40. In some cases, a repair shop can convert a CCFL backlight to LED without installing a new inverter.

Backlight failure in a TV may also be due to failure of the power inverter that supplies power to the backlight. In rare cases, both the inverter and the lighting components fail.

It is not possible to fix a TV capacitor when it fails; it needs replacing. If your TV stops working while you are using it and you notice a smell similar to ammonia or bleach, this is a sign that a capacitor has blown. However, some capacitors do not make any noticeable smell when they blow.

Flat screen replacement glass is not available. The only option for flat-screen TV glass repair is to try optical glass glue, which costs $1.70 for a 5-ml. tube. This may be an option for TV glass repair if the crack is only a few inches or less. TV panels are built as one unit at the factory, with the glass adhered to the display panel.

LCD flat-panel repair is not considered cost-effective. If the glass is cracked or the display is physically damaged, it is cheaper to replace the entire TV than to repair or replace the display panel.

Estimating TV repairs costs by brand is not something TV repair shops offer, however, there are general prices by type. When looking for specific repair costs for your TV, you’ll find them in the common repairs price list above. Pricing applies to brands such as Samsung, LG, Sanyo, TCL, Insignia, HiSense, Sony, Toshiba, Pioneer, and Vizio.

The cost of flat-screen TV repair ranges from $40 to $350. You cannot fix a broken screen, but the price of a new flat-panel TV starts from around $250 for a 1080-mp (non-4K) LED TV from LG to as much as $15,000 for an 85-inch 8K LED TV from Samsung. A TV referred to as a “flat TV” or “flat-screen” TV might be any of the following:LCD TV

An LED TV is just an LCD TV that uses LED backlighting, which all newer models do (older models use CCFL backlighting). The cost to replace one LED backlighting strip ranges from $100 to $125, including parts and labor.

The cost to replace the motherboard, inverter, or LED"s in a 4K TV ranges from $100 to $275 or more, depending on the brand and model. The cost for screen repair for a 4K TV is irrelevant because it cannot be fixed or replaced at a cost that is lower than the cost of a new 4K TV.

Digital light processing (DLP) TVs are also known as projection TVs. DLP big screens have not been made since 2012, and DLP TV repair is usually not worth the cost except for a lamp burnout, in which the bulb can be replaced. The cost to replace bulbs ranges from $60 to $120.

With modern TVs, repair entails component replacement or replacement of capacitors, for which high levels of certification are not necessary. Generally, TV repair shops will let you know if their employees have certification.

If the TV powers on but you do not see a signal from your cable connection, satellite dish, or DVD player,First, check that the connecting cable is securely in the socket on both ends. If that doesn’t work, try substituting another data cable if you have one, or test it with a replacement cable.A data cable $4 to $15

TV Does Not Power OnPlug- If the TV is not powering on and no status LEDs are lighting up, start by plugging the TV into a different outlet. If the TV is too challenging to move, you can run an extension cord from another nearby outlet.

Circuit breaker- Check the circuit breaker for the power outlet that the TV plugs into. You can check the breakers by opening the door to your breaker panel and looking for circuit breakers that are in the OFF position.

Power cable- Check the power cable. If it is a removable cable, you can test it by substituting a power cable from another piece of equipment in your home, or you can buy a replacement cable for this test. The cost for a replacement TV power cable ranges from $2.50 to $10.

Remote control- If the TV is not powering on with the remote control, you should try replacing the batteries. For remote controls with a status LED light, there could be enough power to light the LED but not enough power to send a signal to your TV.

There are many reasons that a TV may power on but have no picture.Backlighting burned out -In modern LCD TVs, the backlighting may be burned out. A technician can replace LEDs or CCFL backlighting strips.

Inverter is bad -It is possible that the inverter, which powers the backlights, has gone bad and needs to be replaced. It’s also possible that one or more capacitors on the inverter have gone bad, in which case a technician may be able to replace capacitors more cheaply than replacing the entire inverter.

Lamp burnout -In a projection TV or older LCD TV, no picture may be caused by lamp burnout. In this case, a technician can replace the bulb quickly and easily.

The right parts- It can be complicated to determine which component of a TV is failing and causing the TV not to work correctly. If you buy a replacement part and perform the repair yourself, the TV may still not work, either because you replaced the wrong part, the part was old and not working properly to begin with, or you did not perform the work correctly. Buying multiple replacement parts can become costly.

The cost of repairing a TV could be as much as $500 if multiple repairs are needed. Consumer Reports recommends not to spend more than 50% of the cost of a new TV repairing the old one.

Not included in these prices from Best Buy are 1080p screens, which range from $250 to $280 for 43-inch TVs from brands like Samsung, Sony, and LG. On the upper end, Sony and Samsung both have 95-inch 8K OLED TVs for $70,000.

In most cases, a flat-screen TV can be fixed. The exception is a physically damaged display panel or screen.  Most other issues including failing speakers, backlights, or power supply. Burned out fuses and damaged input ports can also be repaired.

If the screen is not physically damaged but is not showing a picture or is displaying “snow’” or vertical or horizontal lines, a technician can repair the TV by replacing failed components. If the screen is physically damaged, it cannot be repaired.

You cannot replace a broken flat-screen display. New TVs costs anywhere from $249 for a 1080P (non 4K) LED TV from LG to as much as $14,999 for an 85” 8K LED TV from Samsung.

It seems as though there is a backlight problem but whether this is in the LCD panel, the video cable or cable connector at either end (loose?) or the motherboard would have to be determined first.

Looking at the image you posted it may be not where you indicated but perhaps the wires that are connected to those pins. The last wire looks as though it is broken but it may just be the picture. Also unless what you have shown are pins 38 & 39 it doesn’t apply to the backlights. The pin numbering should be printed on the motherboard. 1 at one end and 40 at the other end of the connector on the board

Here’s an image taken from p.24 of the schematics for the laptop’s motherboard, showing how the backlight power is connected to pins 38 & 39 on the video cable connector.

With the laptop turned on the power is always there. The backlights are turned on and off in the LCD display panel by a signal voltage being present or not on pin 9. (disp on).

If the power is there, turn off the laptop and then gain access to the LCD panel so that you can disconnect the video cable from the panel (and the motherboard) and use an Ohmmeter to check for continuity of the cable’s backlight power wires and the Display On wire from end to end.

It may be easier to source a replacement panel than to replace the LEDs. Usually the part number can be found printed on the back of the panel somewhere. Search online using the part number only to find suppliers.

If your laptop turns on but nothing shows on the screen, there’s a good chance the backlight is out.  The backlight in a laptop is the small CCFL bulb that illuminates the screen, usually from the bottom of the screen.  The light then bounces off of different plastic sheets, passes through the actual LCD pixels, and displays an image.  If this bulb goes out, or if one of it’s critical components go out, the laptop screen dims and it’s extremely difficult to see anything on the screen.

The best way to check is to turn on the computer and let it boot.  A tell-tale sign that it’s the backlight is if the computer boots normally – you hear the log on sound, for example – but nothing shows on screen.  Next, grab a flashlight and aim the flashlight at a sharp downward angle on the LCD.  If you can make out some colors or see your desktop, then you know the backlight isn’t working.  This is one simple test to see if this is the problem you are having.

The above symptoms are signs that there is something wrong with the backlight or other components. The backlight might not be getting enough power or may have a loose connection.

Getting this problem fixed really comes down to a good diagnosis.  Where someone might think it’s the LCD or the bulb itself that is bad, sometimes it is the LCD inverter that is the problem.  The inverter is a small device that transforms the low voltage of the laptop into a higher voltage – enough to turn on the backlight.  In many cases, both the inverter and the backlight are out at the same time.  It takes knowledge and experience to find out which part needs to be replaced.

If you have any questions about an LCD backlight repair, or computer repair in general, please give us a call to speak with one of our expert technicians!

When preparing to add LOCA onto a cleaned iPhone LCD make sure that you remove the working backlight and apply a non working backlight. This will ensure you do not have LOCA bleed through and ruin your working backlight. Remove the backlight using a soldering iron to remove the 3 prongs that attach the backlight to the LCD cable. Make sure you keep the electrical tape tab that covers the 3 connections and reapply it when you put the good backlight back on. If you leave the backlight connection exposed you have a high probability of shorting the connection on the metal frame of the iPhone which can cause strobing and potentially short the backlight fuse or coil which are both advanced logic board soldering.

Before you apply the clean backlight you Must blow the excess LOCA glue out from the edges of the LCD screen and the flex cables at the top of the LCD assembly. I use a compressor with a fine tip and blow the glue out from every angle. Then place the cleaned screen under the UV lamp again to cure any residual glue on the back side as well. I highly recommend cleaning the surfaces with Pure Isopropyl Alcohol or Pure Acetone. Be VERYgentle when cleaning or lifting or moving the LCD flex cables as they are extremely delicate and can be easily damaged leaving all of your separation process utterly worthless.

You should have basic electrical test equipment such as a Digital Multimeter and a basic working knowledge of electronics. Soldering is a must if you plan on doing more than testing a screen.

We will be gaining access under the dreaded “DO NOT TOUCH” plastic tape. What they really mean to say is.. “Do not touch the multiple ribbons along the top or bottom edge of the board.” These ribbons interface with the LCD screen and pass information to the pixel matrix. They are fragile!

This guide applies to Laptop LCD panels more so than your desktop"s 24" LCD screen. Some LED backlights are fed with up to 96 volts, but not usually… and not on laptops.

Finally, if you break something.. it"s on you! There is a lot of variance between LCD manufacturers.. they are all different! Hold only yourself responsible if something goes wrong... that"s an order, not a suggestion

An LED-backlit LCD is a liquid-crystal display that uses LEDs for backlighting instead of traditional cold cathode fluorescent (CCFL) backlighting.TFT LCD (thin-film-transistor liquid-crystal display) technologies as CCFL-backlit LCDs, but offer a variety of advantages over them.

While not an LED display, a television using such a combination of an LED backlight with an LCD panel is advertised as an LED TV by some manufacturers and suppliers.

Unlike OLED and microLED displays, LCDs cannot achieve true blacks for pixels which are illuminated by the backlight. Some LED-backlit LCDs use local dimming zones to increase contrast between bright and dim areas of the display, but this can result in a "blooming" or "halo" effect on dark pixels in or adjacent to an illuminated zone.

The local dimming method of backlighting allows to dynamically control the level of light intensity of specific areas of darkness on the screen, resulting in much higher dynamic-contrast ratios, though at the cost of less detail in small, bright objects on a dark background, such as star fields or shadow details.

A 2016 study by the University of California (Berkeley) suggests that the subjectively perceived visual enhancement with common contrast source material levels off at about 60 LCD local dimming zones.

LED-backlit LCDs are not self-illuminating (unlike pure-LED systems). There are several methods of backlighting an LCD panel using LEDs, including the use of either white or RGB (Red, Green, and Blue) LED arrays behind the panel and edge-LED lighting (which uses white LEDs around the inside frame of the TV and a light-diffusion panel to spread the light evenly behind the LCD panel). Variations in LED backlighting offer different benefits. The first commercial full-array LED-backlit LCD TV was the Sony Qualia 005 (introduced in 2004), which used RGB LED arrays to produce a color gamut about twice that of a conventional CCFL LCD television. This was possible because red, green and blue LEDs have sharp spectral peaks which (combined with the LCD panel filters) result in significantly less bleed-through to adjacent color channels. Unwanted bleed-through channels do not "whiten" the desired color as much, resulting in a larger gamut. RGB LED technology continues to be used on Sony BRAVIA LCD models. LED backlighting using white LEDs produces a broader spectrum source feeding the individual LCD panel filters (similar to CCFL sources), resulting in a more limited display gamut than RGB LEDs at lower cost.

The evolution of energy standards and the increasing public expectations regarding power consumption made it necessary for backlight systems to manage their power. As for other consumer electronics products (e.g., fridges or light bulbs), energy consumption categories are enforced for television sets.

A first dynamic "local dimming" LED backlight was public demonstrated by BrightSide Technologies in 2003,Sony in September 2008 on the 40-inch (1,000 mm) BRAVIA KLV-40ZX1M (known as the ZX1 in Europe). Edge-LED lighting for LCDs allows thinner housing; the Sony BRAVIA KLV-40ZX1M is 1 cm thick, and others are also extremely thin.

LED-backlit LCDs have longer life and better energy efficiency than plasma and CCFL LCD TVs.mercury, an environmental pollutant, in their manufacture. However, other elements (such as gallium and arsenic) are used in the manufacture of the LED emitters; there is debate over whether they are a better long-term solution to the problem of screen disposal.

Because LEDs can be switched on and off more quickly than CCFLs and can offer a higher light output, it is theoretically possible to offer very high contrast ratios. They can produce deep blacks (LEDs off) and high brightness (LEDs on). However, measurements made from pure-black and pure-white outputs are complicated by edge-LED lighting not allowing these outputs to be reproduced simultaneously on screen.

Quantum dots are photoluminescent; they are useful in displays because they emit light in specific, narrow normal distributions of wavelengths. To generate white light best suited as an LCD backlight, parts of the light of a blue-emitting LED are transformed by quantum dots into small-bandwidth green and red light such that the combined white light allows a nearly ideal color gamut to be generated by the RGB color filters of the LCD panel. The quantum dors may be in a separate layer as a quantum dot enhacement film, or replace pigment-based green and red resists normally used in LCD color filters. In addition, efficiency is improved, as intermediate colors are no longer present and do not have to be filtered out by the color filters of the LCD screen. This can result in a display that more accurately renders colors in the visible spectrum. Companies developing quantum dot solutions for displays include Nanosys, 3M as a licensee of Nanosys, QD Vision of Lexington, Massachusetts, US and Avantama of Switzerland.Consumer Electronics Show 2015.quantum dot displays at CES 2017 and later formed the "QLED Alliance" with Hisense and TCL to market the technology.

Mini LED displays are LED-backlit LCDs with mini-LED–based backlighting supporting over a thousand full array local dimming (FALD) zones, providing deeper blacks and a higher contrast ratio.

LED backlights are often dimmed by applying pulse-width modulation to the supply current, switching the backlight off and on more quickly than the eye can perceive. If the dimming-pulse frequency is too low or the user is sensitive to flicker, this may cause discomfort and eyestrain similar to the flicker of CRT displays at lower refresh rates.

Novitsky, Tom; Abbott, Bill (12 November 2007). "Driving LEDs versus CCFLs for LCD backlighting". EE Times. Archived from the original on 28 November 2010. Retrieved 21 November 2020.

Controlling Power Consumption for Displays With Backlight Dimming; Claire Mantel et al; Journal of Display Technology; Volume: 9, Issue: 12, Dec. 2013; https://ieeexplore.ieee.org/document/6520956

LCD Television Power Draw Trends from 2003 to 2015; B. Urban and K. Roth; Fraunhofer USA Center for Sustainable Energy Systems; Final Report to the Consumer Technology Association; May 2017; http://www.cta.tech/cta/media/policyImages/policyPDFs/Fraunhofer-LCD-TV-Power-Draw-Trends-FINAL.pdf Archived 1 August 2017 at the Wayback Machine

This article is about backlights in liquid crystal displays. For the rear window of an automobile, see Car glass. For the lighting design practice, see Backlighting (lighting design). For other uses, see Backlight (disambiguation).

A backlight is a form of illumination used in liquid crystal displays (LCDs). As LCDs do not produce light by themselves—unlike, for example, cathode ray tube (CRT), plasma (PDP) or OLED displays—they need illumination (ambient light or a special light source) to produce a visible image. Backlights illuminate the LCD from the side or back of the display panel, unlike frontlights, which are placed in front of the LCD. Backlights are used in small displays to increase readability in low light conditions such as in wristwatches,smart phones, computer displays and LCD televisions to produce light in a manner similar to a CRT display. A review of some early backlighting schemes for LCDs is given in a report Engineering and Technology History by Peter J. Wild.

Simple types of LCDs such as in pocket calculators are built without an internal light source, requiring external light sources to convey the display image to the user. Most LCD screens, however, are built with an internal light source. Such screens consist of several layers. The backlight is usually the first layer from the back. Light valves then vary the amount of light reaching the eye, by blocking its passage in some way. Most use a fixed polarizing filter and a switching one, to block the undesired light.

An ELP gives off uniform light over its entire surface, but other backlights frequently employ a diffuser to provide even lighting from an uneven source.

Backlights come in many colors. Monochrome LCDs typically have yellow, green, blue, or white backlights, while color displays use white backlights that cover most of the color spectrum.

Colored LED backlighting is most commonly used in small, inexpensive LCD panels. White LED backlighting is becoming dominant. ELP backlighting is often used for larger displays or when even backlighting is important; it can also be either colored or white. An ELP must be driven by relatively highAC power, which is provided by an inverter circuit. CCFL backlights are used on larger displays such as computer monitors, and are typically white in color; these also require the use of an inverter and diffuser. Incandescent backlighting was used by early LCD panels to achieve high brightness, but the limited life and excess heat produced by incandescent bulbs were severe limitations. The heat generated by incandescent bulbs typically requires the bulbs to be mounted away from the display to prevent damage.

For several years (until about 2010), the preferred backlight for matrix-addressed large LCD panels such as in monitors and TVs was based on a cold-cathode fluorescent lamp (CCFL) by using two CCFLs at opposite edges of the LCD or by an array of CCFLs behind the LCD (see picture of an array with 18 CCFLs for a 40-inch LCD TV). Due to the disadvantages in comparison with LED illumination (higher voltage and power needed, thicker panel design, no high-speed switching, faster aging), LED backlighting is becoming more popular.

LED backlighting in color screens comes in two varieties: white LED backlights and RGB LED backlights.blue LED with broad spectrum yellow phosphor to result in the emission of white light. However, because the spectral curve peaks at yellow, it is a poor match to the transmission peaks of the red and green color filters of the LCD. This causes the red and green primaries to shift toward yellow, reducing the color gamut of the display.a red, a blue, and a green LED and can be controlled to produce different color temperatures of white. RGB LEDs for backlighting are found in high end color proofing displays such as the HP DreamColor LP2480zx monitor or selected HP EliteBook notebooks, as well as more recent consumer-grade displays such as Dell"s Studio series laptops which have an optional RGB LED display.

RGB LEDs can deliver an enormous color gamut to screens.additive color) the backlight can produce a color spectrum that closely matches the color filters in the LCD pixels themselves. In this way, the filter passband can be narrowed so that each color component lets only a very narrow band of spectrum through the LCD. This improves the efficiency of the display since less light is blocked when white is displayed. Also, the actual red, green, and blue points can be moved farther out so that the display is capable of reproducing more vivid colors.

A newNanosys, claims that the color output of the dots can be tuned precisely by controlling the size of the nanocrystals. Other companies pursuing this method are Nanoco Group PLC (UK), QD Vision, 3M a licensee of Nanosys and Avantama of Switzerland.Sony has adapted Quantum Dot technology from the US company QD Visionedge-lit LED backlight marketed under the term Triluminos in 2013. With a blue LED and optimized nanocrystals for green and red colors in front of it, the resulting combined white light allows for an equivalent or better color gamut than that emitted by a more expensive set of three RGB LEDs. At the Consumer Electronics Show 2015, Samsung Electronics, LG Electronics, the Chinese TCL Corporation and Sony showed QD-enhanced LED-backlighting of LCD TVs.

CCFL backlighting has also improved in this respect. Many LCD models, from cheap TN-displays to color proofing S-IPS or S-PVA panels, have wide gamut CCFLs representing more than 95% of the NTSC color specification.

There are several challenges with LED backlights. Uniformity is hard to achieve, especially as the LEDs age, with each LED aging at a different rate. Also, the use of three separate light sources for red, green, and blue means that the white point of the display can move as the LEDs age at different rates; white LEDs are also affected by this phenomenon, with changes of several hundred kelvins being recorded. White LEDs also suffer from blue shifts at higher temperatures varying from 3141K to 3222K for 10 °C to 80 °C respectively.Benq G2420HDB consumer display has a 49W consumption compared to the 24W of the LED version of the same display (G2420HDBL).

To overcome the aforementioned challenges with RGB and white LED backlights an "advanced remote phosphor" cockpit displays,Air Traffic Control displays and medical displays. This technology uses blue pump LEDs in combination with a sheet on which phosphorous luminescent materials are printed for colour conversion. The principle is similar to Quantum Dots, but the phosphors applied are much more robust than the quantum dot nano-particles for applications that require long lifetime in more demanding operational conditions. Because the phosphor sheet is placed at a distance (remote) of the LED it experiences much less temperature stress than phosphors in white LEDs. As a result, the white point is less dependent on individual LEDs, and degrading of individual LEDs over lifetime, leading to a more homogenous backlight with improved colour consistency and lower lumen depreciation.

The use of LED backlights in notebook computers has been growing. Sony has used LED backlights in some of its higher-end slim VAIO notebooks since 2005, and Fujitsu introduced notebooks with LED backlights in 2006. In 2007, Asus, Dell, and Apple introduced LED backlights into some of their notebook models. As of 2008Lenovo has also announced LED-backlit notebooks. In October 2008, Apple announced that it would be using LED backlights for all of its notebooks and new 24-inch Apple Cinema Display, and one year later it introduced a new LED iMac, meaning all of Apple"s new computer screens are now LED. Almost every laptop with a 16:9 display introduced since September 2009 uses LED-backlit panels. This is also the case for most LCD television sets, which are marketed in some countries under the misleading name LED TV, although the image is still generated by an LCD panel.

Most LED backlights for LCDs are edge-lit, i.e. several LEDs are placed at the edges of a lightguide (Light guide plate, LGP), which distributes the light behind the LC panel. Advantages of this technique are the very thin flat-panel construction and low cost. A more expensive version is called full-array or direct LED and consists of many LEDs placed behind the LC panel (an array of LEDs), such that large panels can be evenly illuminated. This arrangement allows for local dimming to obtain darker black pixels depending on the image displayed.

For a non-ELP backlight to produce even lighting, which is critical for displays, the light is first passed through a lightguide (Light guide plate, LGP) - a specially designed layer of plastic that diffuses the light through a series of unevenly spaced bumps. The density of bumps increases further away from the light source according to a diffusion equation. The diffused light then travels to either side of the diffuser; the front faces the actual LCD panel, the back has a reflector to guide otherwise wasted light back toward the LCD panel. The reflector is sometimes made of aluminum foil or a simple white-pigmented surface.

The LCD backlight systems are made highly efficient by applying optical films such as prismatic structure 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),

The evolution of energy standards and the increasing public expectations regarding power consumption have made it necessary for backlight systems to manage their power. As for other consumer electronics products (e.g., fridges or light bulbs), energy consumption categories are enforced for television sets.

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Dimming options for LCD brightness; J. Moronski; Electronicproducts.com; 3 Januari 2004; "Dimming options for LCD brightness control". March 2004. Archived from the original on 28 July 2017. Retrieved 20 November 2017.

LCD Television Power Draw Trends from 2003 to 2015; B. Urban and K. Roth; Fraunhofer USA Center for Sustainable Energy Systems; Final Report to the Consumer Technology Association; May 2017; "Archived copy" (PDF). Archived from the original (PDF) on 1 August 2017. Retrieved 20 November 2017.link)

Controlling Power Consumption for Displays With Backlight Dimming; Claire Mantel et al; Journal of Display Technology; Volume: 9, Issue: 12, Dec. 2013; Mantel, Claire; Burini, Nino; Nadernejad, Ehsan; Korhonen, Jari; Forchhammer, Soren; Pedersen, Jesper Meldgaard (2013). "Controlling Power Consumption for Displays with Backlight Dimming". Journal of Display Technology. 9 (12): 933–941. Bibcode:2013JDisT...9..933M. doi:10.1109/JDT.2013.2260131. S2CID 24082090.

Hello I purchased a new GTS 330m for my Asus G60JX and for some reason my backlight wont turn on. The screen is on because I can see a dim picture and when connected to VGA or HDMI I get a picture on the screen.I forgot to mention I tried 2 other Internal screens and the back light on none of them worked. I even tried a different vga cable I had and the same results. I only get picture with VGA and HDMI. I need to know if the video card is the problem? Would the picture show through VGA and HDMI if the Video card is bad? Please any help would be great.

My monitor is not turning on even though it is plugged in (external power supply)First, try another device in the same outlet to determine if the outlet is working properly.

Is everything firmly plugged in? It is easy for cables to become loose and not firmly connected, especially if you are using a mobile system. Please check to ensure everything is securely plugged in.

The LED light on the power supply should be GREEN. If the LED light is not on, then either the power supply is dead or there is no power being generated from the power source. Try another power source (outlet) and if this doesn’t work, there may be an issue with the power adapter.

Amber Light: The amber light indicates the monitor is receiving power but is not receiving the video signal being fed from the signal source (camera, computer, etc). This may also signify that the monitor is currently set to the wrong video input; you may need to press the “Auto/Switch” button to select the appropriate input (VGA, HDMI, etc).

My monitor is not turning on even though it is plugged in (internal power supply)First, try another device in the same outlet to determine if the outlet is working properly.

Is everything firmly plugged in? It is easy for cables to become loose and not firmly connected, especially if you are using a mobile system. Please check to ensure everything is securely plugged in.

Amber Light: The amber light indicates the monitor is receiving power but is not receiving the video signal being fed from the signal source (camera, computer, etc). This may also signify that the monitor is currently set to the wrong video input; you may need to press the “Auto/Switch” button to select the appropriate input (VGA, HDMI, etc).

My monitor screen is completely black, even though it is powered onIs everything firmly plugged in? A loss of video signal will cause the monitor to go black and then turn off entirely. It is easy for cables to become loose and not firmly connected, especially if you are using a mobile system. Please check to make sure everything is securely plugged in.

Your monitor possibly has TRU-Vu’s Dim-To-Black feature which allows you to control the screen’s brightness and contrast by pressing the arrow keys in the menu. The reason it has gone completely black could be because the dim-to-black was turned all the way down. Press the arrow up to the right to raise the brightness again. If this does nothing, try pressing the left arrow keys.

Why does my monitor keep entering sleep mode when I turn it on?The primary cause is usually that the monitor is not receiving a video signal from the signal source (camera, computer, etc). The monitor will automatically enter sleep mode if it cannot detect a video signal.

If the LED on the monitor is amber, this means the monitor is receiving power but not receiving a video signal from your source. Ensure the monitor is set to the correct input and try swapping out sources to determine if that is the root of the problem.

Why are there black bars and/or squeezing (banding) with my monitor?If there are black bars around your signal and/or a “squeezing” effect, this means that the aspect ratio of your monitor and the incoming video signal do not match.

Make sure the monitor’s picture size setting is set to the factory default, not zoom, fit or stretch. For optimal picture quality without distortion, black bars or squeezing, it is always best to match the aspect ratio of your video signal with the aspect ratio of the monitor.

My touch screen is not working.All touch panels must be connected to a computer via USB or RS232 cable. This allows the touch panel to communicate with the computer.

If you recently downloaded a new touch panel driver, you must also delete the old driver and reboot your computer. Make sure you have deleted any old touch panel drivers and then restart your computer.

My touch screen is not registering correctlyAll non-HID compliant touch panels will need to be calibrated during the initial start-up and may need recalibrating at some other point in the future. This is accomplished via the touch panel software installed on your computer. For a detailed walk through, please contact us.

Certain touch panels are susceptible to issues due to grease/dust/water and therefore may need added care. If this is a constant problem, please contact us for further assistance.

The buttons on my monitor are lockedKeylock is a safety feature offered by TRU-Vu to prevent unauthorized personnel from changing the desired monitor settings. We do not publish the lock codes for public knowledge; please contact us for the unlock codes.

The speakers are not very loud on my monitorTRU-Vu speakers are provided for signals and alerts; these are not intended for voice or music. If quality of sound is a major concern, we advise using external speakers.

It is always recommended to spray the microfiber cloth first, then clean the screen with the moistened cloth. Do NOT spray the monitor screen directly.

For heavier duty cleaning, create a solution of 80% alcohol mixed with 20% water and use the damp, not wet, cloth to clean the screen and panel surface.