lcd screen backlight voltage price

This is a universal LED kit that includes 2 high brightness LED strips, a DC-DC LED driver, and a wire harness.  The LED strips can be easily trimmed in designated increments every 3 LEDs, to fit any size LCD from 10.4"-19". This is known as a cut-to-fit model. This LED bar can be used for LED replacement or CCFL conversion.

Make sure you have an appropriate power supply before installing.  The driver is expecting analog DC voltage.  The driver is designed to operate 2 LED strips at the same time; operating only 1 LED strip may have higher brightness but will reduce the life of the LED strip (to less than 10,000 hours).  If connecting Single LED Strip directly to analog DC source, the recommended input is 10V-11V DC.

NOTE: Plazmo does not have user manuals because every model of LCD power supply board is different.  The customer must have some technical expertise to identify the power source on the monitor power supply board.

This product is commonly used for replacing backlights in a variety of different LCD panels found in gaming machines, POS, ATM and many other applications.

This is a universal LED kit that includes 2 high brightness LED strips, a DC-DC LED driver, and a wire harness.  The LED strips can be easily trimmed in designated increments every 3 LEDs, to fit any size LCD from 10.4"-24". This is known as a cut-to-fit model. This LED bar can be used for LED replacement or CCFL conversion.

Make sure you have an appropriate power supply before installing.  The driver is expecting analog DC voltage.  The driver is designed to operate 2 LED strips at the same time; operating only 1 LED strip may have higher brightness but will reduce the life of the LED strip (to less than 10,000 hours).  If connecting Single LED Strip directly to analog DC source, the recommended input is 10V-11V DC.

NOTE: Plazmo does not have user manuals because every model of LCD power supply board is different.  The customer must have some technical expertise to identify the power source on the monitor power supply board.

This product is commonly used for replacing backlights in a variety of different LCD panels found in gaming machines, POS, ATM and many other applications.

Broken LCD, or flickering display, or a dull dark display, we have the solution. We can repair or replace the LCD. Backlight or display card problem we have solution for all.

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.

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 2017-07-28. Retrieved 2017-11-20.

Energy Efficiency Success Story: TV Energy Consumption Shrinks as Screen Size and Performance Grow, Finds New CTA Study; Consumer Technology Association; press release 12 July 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 2017-08-01. Retrieved 2017-11-20.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.

Since the 2010’s, cold cathode fluorescent lamps (CCFL) in liquid crystal display (LCD) backlighting have been gradually replaced by light-emitting diodes (LED). This is because LEDs, which contain no mercury, have outperformed in thermal dissipation efficiency, color rendition and cost reduction.

Various LCD TV manufacturers, one after another, have eagerly adopted LED backlighting technology for LCD to achieve the feature of low profile, aiming to increase market share on the arrival of the new home TV generation. The market penetration of LED backlit models has been soaring that most of the LCD TVs are LED backlit on Taiwan’s market today.

LED backlighting technology can be divided into two groups: direct-lit type, and edge-lit type. LEDs, used in direct-lit type backlighting, can be either white or RGB. The differences between these two types and LED power solutions in system perspective will be investigated in this application note. For example, the functional block diagram of a 4-CH LED driver, RT8510, used in notebook computers, is illustrated in Figure 2. The upper block is Boost Converter, providing the voltages needed for LED strings, and the lower block is Constant Current Dimming Controller.

Backlight Modules, as the lighting source of LCDs, consist of light sources, light guides and backlight diffuser plates, etc. As LCD TVs and laptops have become increasingly prevalent, the development focus is to incorporate energy-efficient LED backlight modules into the systems in response to the trend of large-scale and low-profile panels.

For edge-lit LED backlighting technology, white LEDs are placed around the four sides of the LCD, and the light is emitted through between the LCD panel and the reflector sheet, by which the light is reflected to the back of the LCD panel. The light guide plate spreads the light evenly across the back of the LCD. This is by far the most commonly used LED backlighting technology with advantages of low cost and low profile.

For direct-lit backlighting technology, LEDs are placed in a flat array behind the light guide plate and the LCD screen, which the light is directly emitted to. This method allows for fast locally dimming LEDs for specific areas of brightness on the screen to greatly enhance dynamic contrast. The disadvantage, however, is that more LEDs are to be used, which will then increase product cost and also the thickness of the backlight module. White LEDs are most commonly used for LED backlighting, while for some high-end models, RGB LEDs are used for wider-gamut color rendition.

The commonly used power architecture for today’s TV models is that LLC or Flyback systems provide DC power supply to boost or buck converters, which then drive LED arrays, and LED Current Regulator clamps the current at the desired LED brightness. Nevertheless, in recent years, LED arrays can be found directly driven by an LLC or a Flyback system, while the voltage of the previous stage is adjustable by controller ICs.

Figure 5 is the application schematic diagram of a power solution. The RT8525, on the left-hand side, as a DC-DC Boost Converter, provides sufficient voltages to drive LED arrays. The RT8300, as a Current Regulator, provides constant current and dimming function. DHC (Dynamic Headroom Control) connects these two ICs as a feedback control. When the backlight module is turned on, the forward voltage, Vf, of the LED will decrease due to the increasing temperature. If the output voltage remains fixed, the terminal voltages on LED 1~4 pins will then increase. It will cause both the power dissipation and the temperature of the RT8300 to rise. Consequently, it will result in the decrease of overall efficiency and the failure of surface temperature requirement for the ICs. Therefore, there must be a mechanism to make the boost converter lower down its output voltage.

Dynamic Headroom Control (DHC) function is created for this purpose. The RT8300 will find out which channel has the lowest terminal voltage on LED 1~4 pins among all LED channels and will clamp the desired operating voltage by the curve in Figure 6. This voltage has a linear relationship with the LED current.

If the pin voltage for that lowest-voltage channel is higher than the corresponding value in Figure 6, the RT8300 VFB pin will be set high. Through R3 to VREF, the output voltage (VLED) will be lowered. Vice versa, if the pin voltage is too low, VFB pin will be set low and the output voltage will be pulled higher. Figure 7 shows the schematic and the corresponding equations, which are based on the Superposition Theorem.

For different applications, the wattages of their backlight modules will be different. Generally, the larger LCD panels, the more LED arrays to provide for the desired brightness will be needed. The power dissipations for ICs and power devices will thus be increased, which deteriorates the thermal performance. Compared to the power solutions for the backlights of notebook computers, the desktop monitors demand greater power. Therefore, it is better the MOSFETs are connected externally instead. For applications of even higher wattages, such as LCD TVs, even the drivers of current source devices will be connected externally in order to lower down the surface temperature of ICs. The following lists Richtek LED backlight power solutions for various applications.

All electronics products have specifications with regard to audible noises. When portable electronics products become more and more prevalent, the noise specifications for their backlight modules are even stricter. The audible noises usually arise when the applications operate in PWM dimming mode. The noises mainly results from the resonance, caused by the output capacitance, MLCC, and the output current switch. In PWM dimming, PWM LED current switches between heavy and zero loads. The abrupt changes of the loads will increase the ripples of the output voltage. Such ripples to human ears are audible noises. Figure 9 shows the waveform diagram of the RT8510 when dimming.

5.Use larger OVP resistors: When PWM is off, larger OVP resistors will lower the load and the output dropout voltage, and so the noises can be reduced.

6.Replace with an MLCC from the noise reduction solution: The output capacitance will affect how large the ripples are. Large ripples may cause resonance in between the layers, which will induce noises. The noise-reduction capacitors have the superior performance over the cross-voltages, that is, less capacitance change at higher DC biases. Figure 10 shows the comparison of the equivalent MLCC capacitances between the new (noise-reduction) and conventional fabrication processes.

1.SLP (Short LED Protection): If any LED(s) in the LED string is connected short when mounted on the surface, the overall forward voltage Vf of the LED string will be lower, which will results in higher VLEDX terminal voltage. SLP is to detect whether the VLEDX voltage is too high. For some models, only the short channel will be off, while for others, it is the driver circuit to be turned off. Users can adjust SLP voltage via RSLP.

2.OLP (Open LED Protection): If any LED(s) in LED strings are in poor contact, whether in assembly or in use, OLP is to detect whether the VLEDX voltage is too low when power-on, and will send out the warning signal accordingly.

3.OVP (Over Voltage Protection): When the overvoltage occurs at the output voltage, OVP will detect it by the voltage divider. It will clamp the output voltage at the voltage set by OVP, without turning off the circuitry. Figure 12 shows the RT8300 protection mechanism flow.

In 3D mode, due to the decreased PWM duty, the higher brightness from backlight modules is needed. The images perceived by human’s right/left eyes will be alternately displayed to generate the effect of field of depth. Figure 13 illustrates a 3D dimming functional diagram. The LED driver, RT-CVT, demands that the 3D-glasses shutters be synchronized with Main Board in order to effectively block left and right eyes alternately.

This approach is used for advanced models to enhance the contrast. The blacks with local dimming are perceived darker because the backlights of that section are dimmed. On the contrary, the backlights behind brighter sections can be brighter. Henceforth, local dimming has the advantage of consuming less power. Figure 14 illustrates an example of a 64-zone local dimming. The more zones the screen is divided into, the more noticeable the benefit of local dimming is. However, the trade-off is the complexity of control and cost will be correspondingly increased.

The architectures for LED backlight driving systems vary in accordance with various requirements, such as energy efficiency, cost down and performance enhancement. The driver ICs should then be changed accordingly. Furthermore, to power LED strings, the power solutions should change with the applications (TV/ Monitor/ Notebook/ Tablet). Finally, to tackle the audible noises, to enhance the system efficiency, and to meet the surface temperature requirements for all the components are also important aspects to consider for customers.

The LCD screen on your phone, with all of its rich colors and detail is just a dim slab of nothing without the backlight. Looking at a replacement screen, you"ll see the wide digitizer cable, and the smaller LCD cable carrying the data to color the pixels of the screen. Looking even closer you can see a thin little third flex soldered to the assembly. This the backlight flex. Through this flex flow the electrons that light a tiny strip of LED lights---the backlight. The light is diffused and spread around nicely by several backlight sheets. The whole thing is married to the back of the LCD. As long as the electrons march through the flex, the strip of LEDs light, and the backlight comes on.

The brains of the display is the Power Management ic chip. This guy generates a voltage that is passed to the coil. Remember a voltage is a hill for the river of current to flow down.

The magical power of the coil is to boost power. The coil, or inductor, can transform the relatively small incoming voltage from the Power chip into the big 15-20 V required to light the energy sucking display. The flow of current through the coil does some magiccalled electromagnetic induction that can be at once incredible and overwhelming. But really, it is just mechanics. When electrons go for a swirly ride through a coil, they generate a big voltage. A big voltage that can push electrons all the way to through to the flex and light the LEDs. All we need to know is "The coil. Big Slinky. Sturdy. Boost voltage" In order for the coil to stop working, you"d have to come by and snip off the wire as it connects the coiled spiral of wire inside to the pad below the component. Practically, this can only happen in very specific cases of water damage, where water essentially eats the base wire of the coil. Since the days of the iPhone 3Gs, modern coils are surrounded by waterproofing. Hence--they never fail.

The diode is a cop, a bouncer, an organizer--it will only let electrons file across its sensitive middle if they move along single file from one side to the other. It is constructed from delicate materials--chocolate on one side, vanilla on the other. Red light. Green light. And that kind of makes it prissy. It is not a simple semiconductor--not like a wire or a rod. No. Inside it has two different materials seamed together. This is what makes it directional, it stands on two simple pads, and you must install it only one way. Guess what happens to the poor little guy if an excessive unregulated voltage were to hit it? Like, say, someone pokes a screwdriver snagging a component to the frame, shorting the circuit? The diode will wilt like the delicate flower it is, and let out its magic black smoke. We all know that once any component lets out it magic black smoke, it is curtains.

Wait, backlight diode? What? You may be skeptical. You may not have heard about the backlight diode before. However, I"ve bet you"re heard of "the backlight ic." News flash. In modern phones and iPads, they are the same. Identical. An ic, or integrated circuit, is an overstretched promotion for the simple diode. This misuse of terminology was intentional. When folks started hiring other people to fix their iphone backlight circuits, the implication that what was being done was the installation of some sort of ic chip perpetuated a sense of difficulty of the operation. While some phones do have a small ic providing some logic for the backlight, nearly all iPhones and iPads today just have a simple diode. The terminology "backlight ic" remains because--- "Install an ic, means hire a professional" "Install a diode, means give it a shot myself"

The intact filter is required to complete the path from the diode to the LCD connector. The problem is that they tend to be very susceptible to 1.) water damage and 2.) current spikes. In practice, the filter is the first component to go when the circuit is in trouble. As such, they act as a fuse. Intentional or not, I don"t know. However, when a sudden drop in voltage from pulling the LCD connector in the iPad mini while the battery is still connected causes a transient spike in amperage, like a dutiful Romeo, the backlight filter will sacrifice itself, breaking continuity. Some backlight circuits have one filter, some have two or three. All of them are required for the intact delivery of the voltage necessary to light the LCD.

The last guy in the line is the LCD connector. Most of the pins of the connector are receiving data to build the image on the LCD. Only a few pins are required to deliver the voltage to the backlight LEDs. Can you guess which ones they are? Take a look at the LCD connector of any water damaged phone. Look for a pin that is the blackest with the most chewed up pad--that"s the one meant to carry the big voltage for the LCD display.

Normally, a failure in any component of the backlight circuit will cause a dark display when the device is on. However, in later model full sized iPads--the iPad 3, 4 and Air things are a wee bit more complex. The backlight circuit is split into two. There are two coils, two diodes, two filters that come together to feed one LCD connector. This strange situation can result in this common problem:

Give yourself a star if you chose B. No backlight is a CLASSIC and COMMON problem in all mobile devices. It is almost always repairable, you just have to know where to look.

Once done, hunt for the backlight filters. They may be near or far from the LCD connector. You are looking for ceramic components with a black center. Think ferrite bead = iron= black and find them. (I can"t believe that this little relationship just occurred to me for the very first time right now.) If they are damaged, they will not have continuity from one side to the other. Get out your multimeter. Set it to continuity testing. If you don"t hear a beep on the backlight filter, that"s the problem. Many times, if the backlight filter is severely burned, it has become welded inseparably from the underlying pad. In these cases, it is not possible to replace the component. But it is still possible to save the device---build a custom microjumper to restore continuity in the line. If you do find a backlight filter that looks severely burned, then

Check out the diode. If you find the filter you can find the diode using your multimeter even if you"ve never seen the device before. Put one probe on the end of the filter. Stab around with the other probe until you find a diode-looking component that has continuity with the filter. That"s the backlight diode! Test the diode. Set your multimeter for diode testing. Measure black probe to one side red to the other. Reverse probes. You should get a "1" = infinite resistance in one direction, but not the other. If you get a "1" in both directions, replace the diode. Remember that the new diode should go in the same direction as the original diode! After you have done this, and your device will still not show a backlight with a known good display, THEN and ONLY THEN should you consider the coil. But honestly,