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LCD Backlights—What You Need to Know About LED, CCFL, & LCD Repairs

The world of LCD backlights can be a confusing one. Determining the right option for your LCD screen can be a challenge as a result. The solution you choose depends on the application, frequency of use, and perhaps your budget. However, different types of backlighting produce different results.

Whether you’re looking to replace your LCD lighting with LED or CCFL lights or just want to know which option is best for you, this brief guide will help you better understand what LCD backlighting is and what options are available.

 

Why LCD Backlighting?

First, let’s explore what LCD backlighting is. If you’ve made it this far, chances are you already have a general idea, but for those of you who don’t, LCD stands for Liquid Crystal Displays. Because pixels in LCDs are similar to shutters, their contrast relies on the underlying electrical current. To properly illuminate an LCD, a light source must be placed behind the color pixel panel.

It’s important to note that not all LCDs use a backlight. Backlighting simply allows the viewer to see the display more clearly in low light conditions. For commercial purposes, this is important since the consumer must be able to use the screen properly regardless of the external lighting conditions.

 

Commercial Applications for Backlights

Any LCDs in use require backlights to function properly and over the long haul. Some common commercial applications for them include:

  • POS Cash Registers
  • ATM Cash Machines
  • Casino Gaming Machines
  • Gas Station Pumps
  • Ticket and Vending Machines
  • Medical and X-ray Imaging equipment
  • Navigation and GPS
  • Fitness Equipment

LCD displays often run 24/7, which means they lose their brightness over time, often in 3 years or fewer. That’s why replacements are often necessary. There are two primary types of LCD backlighting replacements—CCFL and LED.

 

How CCFL Replacements Work

CCFL stands for Cold Cathode Fluorescent Lamps. These backlights work very much like the traditional fluorescent lamp and come in a single straight or shaped glass tube. Inside the tube is low-pressure mercury vapor. Once ionized, it emits ultraviolet light. Since humans cannot detect UV light, a coat of phosphorus inside the tube translates it into a white bright light that we can see.

 

How LED Replacements Work

LED stands for Light-Emitting Diode. LED backlights work much differently than CCFLs in that they require 10 to 18 white individual LEDs. They are laid in a uniform pattern. To make things even more complex, white LEDs are actually blue LEDs with a yellow phosphor coating that causes us to see a white light.

To control where and how light is displayed on your chosen screen, a display panel consisting of two sheets of polarizing material with a liquid crystal solution placed in between is utilized. Again, this is where an electric current comes into play. That current will pass through the liquid. The result is a pattern based on how the crystals align, depending on if the light should or shouldn’t pass through it. Crystals serve as a barrier to create the resulting light display.

Keep in mind that both CFFL and Led can be custom tuned to produce nearly any color and color temperature of light. However, they each have different advantages and disadvantages.

 

Advantages of Using CCFL Replacements

CCFLs are the traditional standard for backlighting. They are the tried-and-true option for backlighting any LCD display. Why? There are several reasons.

First, they provide high brightness levels. That’s important for any LCD display because its brightness has a direct effect on the viewing quality.

Second, they have a long lifetime. They can go for years without needing to be replaced.

Third, they offer superior uniformity for just about any type of display.

CCFLs are the go-to for most display purposes. 

 

Advantages of LED Replacements

On the other hand, LED backlights are getting more traction as of late. They are relatively new and most experts consider them the backlighting preference of the future. Most new displays are only available with LED replacements. However, LEDs do come with one major downside—they cost more than CCFLs, sometimes twice as much. Keep in mind, it is typically best to stick with using the type of backlight that your OEM screen was designed to use, regardless if it is LED or CCFL. One exception is if you have customized your display for LED use.

Yet, some of the advantages of choosing an LED include superior brightness levels, no inverter is required (only a power supply), durability is better, and they can provide longer life (for more cost).

 

Different Types of LED Backlighting

Depending on your application, other types of backlighting might also be available. LCD TVs, for example, use both full-array and direct local backlighting. Direct local dimming is similar to full-array, but there are fewer LEDs spread across a wider area than you’d see with full-array backlighting. For manufacturers, however, there is a difference. LEDs that are spaced farther apart do not have the same consistency or accuracy in lighting that full-array displays do.

 

How to Repair an LCD Backlight

If your LCD screen is dimming and not offering the same consistent bright display as it once did, it could be time for repairs. A common repair is CCFL or LED replacement. In fact, companies like Plazmo make exact OEM replacements for the original backlight in the LCD, regardless if it is LED or CCFL.

LCD repair or removing and replacing LCD backlighting is simple but does require some steps. It is far more cost effective than total replacement as well. Your LCD is unique, which means you need to carefully analyze the manufacturer’s information before you go about removing the previous CCFL backlight. You’ll likely need to remove any outer casing you encounter and possibly the screen itself, depending on the application.

You will also have to work around a copper ground or LCD controller board because these often limit access to the backlight. Noting where you removed these items and where they should go back to is important during the removal process.

Next, access the CCFL bulb. Often it has its very own spot. Remove the rubber caps from the previous bulb and add them to your replacement bulb. Run the power cable back into one end of the new bulb—potentially using a soldering tool to do so. If you don’t want to do the rebuilding of your CCFL assembly, check out our mail in repair services here.

After you finish these steps, replace the CCFL and any other components back into your display and test the result.  In the vast majority of cases, your screen will be returned to its full brightness potential, just like new.

Possible Additional Repairs

Did replacing your bulb not do any good? Then you might be dealing with dying capacitors, inverters, or transistors. You’ll need electrical equipment like a voltmeter, to take a measurement of the electrical current flowing into important components.

 

When to Contact a Professional for LCD Backlighting

Whether you aren’t quite sure which backlight your LCD repair needs, or you have not been able to find the CCFL or LED for your screen anywhere, it might be time to contact a professional. Finding the correct backlight can be challenging and getting it wrong can cause you a serious headache.

The good news is, if you opt to choose Plazmo for your replacement parts or LCD repairs, you’re in good hands. We offer affordable replacements that get your screen back to its original brightness without the high costs of buying an entirely new panel.

Give our site a browse to find the right components for your LCD display or contact us at sales@plazmo.com  if you’d like to have us do the heavy lifting for your repairs.