lcd screen light spot quotation

Liquid crystal display (LCD) is a flat panel display that uses the light modulating properties of liquid crystals. Liquid crystals do not produce light directly, instead using a backlight or reflector to produce images in colour or monochrome.

In the meantime, I"ve got two possibilities as to the cause to mention. The first would be damage to the LCD screen itself. It kind of looks like what happens when water gets into the edge of the screen. If that"s the problem, then there"s really nothing you can do about it. Sometimes liquid damage will rectify itself as the liquid evaporates the screen may return to normal. Otherwise your choices come down to basically either live with it or get a new TV. Replacement LCD panels for large screen televisions tend to be either not available or uneconomical to replace; the cost is frequently equal to or greater than the price of just replacing the whole TV.

The other thing that could cause that sort of effect is the backlights. The backlights consist of a bunch of white LEDs behind a white sheet of diffuser to even out the light. Even that isn"t sufficient, so each tiny LED has a lens on the top of it to spread the light out more evenly. Here"s a picture of some single backlights, although they usually come in longer strips.

What happens is that sometimes those clear plastic domes fall off. When that occurs, instead of the light being spread out, it gets concentrated in one spot like what you"re seeing. If that turns out to be the problem, then your prospects for being able to fix it jump up considerably. It"s not exactly a simple thing to replace backlights, but it is doable for us home DIY-ers. The LEDs themselves aren"t terribly expensive, and in your case you could almost certainly get by with just replacing the single strip with the missing lens. Best case you find the lens inside the TV and manage to glue it back on, costing you nothing.

another story - going back like 20 years, when Roland first came out with touch screens on their units - they had given me one as an advance unit. The backlight lasted a very short time, like days. And then, months later, they had this big unveiling party and they said they waited to put out touch screens because they wanted them to be reliable. When they added "our touch screens won"t go bad", I just busted out laughing. As I was on my 3rd device before the unit was even available to the general public.

CTL display products are manufactured to rigorous standards. Our display products are consistently recognized as among the highest quality display products in the industry. Nevertheless, due to the nature of LCD technology, an LCD display may exhibit a small number of very small bright or dark spots on the screen. Often, these spots are noticeable only when the screen continuously displays a certain solid color such as an all-white or all black background. This type of background can be present when initially turning a computer on, or when a computer switches the display to a specific screen-saver.

Occasionally, these spots can seem to appear when a user switches to a different desktop background image. In actuality, these spots are pixels or sub-pixels that are stuck always on (viewable as a bright spot on a dark background) or always off (viewable as a dark spot on a light background).

An LCD display is made up of tens of thousands of individual pixels, and each pixel is made up of 3 individual sub-pixels (red, blue and green). In-fact, a 17" LCD has over 1,300,000 pixels and almost 4 million sub-pixels! Each sub-pixel is controlled by an individual transistor which turns the individual sub-pixel that it controls either on or off to create the image on your screen. An anomaly occurring during the manufacturing process can cause an individual transistor to continuously light or fail to light an individual pixel element, causing one of these small spots on the screen. Although this anomaly occurs relatively rarely in individual transistors, there are millions of sub-pixels on each LCD screen, and it is not uncommon for an LCD screen from any manufacturer to contain a few of these transistor anomalies and their associated bright or dark spots. For a manufacturer to sell only LCD""s with no transistor anomalies would result in a prohibitive cost to you, the consumer…one many times higher than it is today. Most people and applications are tolerant of a small number of these transistor anomalies on an LCD screen, and prefer the lower cost of LCD""s that existing standards allow.

CTL sets simple & strict limits as to the allowable number of non-performing pixels or sub-pixels on our LCD display and laptop computer screens. These criteria supplement our existing Warranty and are applicable during the warranty period for all CTL and 2go LCD displays as follows:

The LCD display of products under warranty will be replaced if CTL determines that it has 6 or more bright sub-pixels, 6 or more dark sub-pixels or a combination of 6 or more bright and dark sub pixels.

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.

There might be a lot of other root causes for similar symptoms, a black screen often looks like something very serious and therefore expensive to repair, but this case is the perfect example that taking some time to look for the root cause can sometime lead to a good surprise: here a 1$ fix!

I have a mid 2014 MacBook Pro Retina 13", which was purchased in March 2015. In June 2015, I noticed a single bright spot mura located about 1.5" above the F7 key. I called Apple Support and reported the screen defect. Apple Support was excellent and only wanted to confirm that the defect was not dead pixels (dead pixels may be indicated by their geometric/square shaped pattern). Apple Support told me to go to my local Apple Store and have a Genius inspect and assess the mura. I made a Genius appointment and brought my MacBook in. The Genius had no problem confirming the mura and said that it was a manufacturer defect that is covered under the Apple warranty. The Genius stated that they would send my MacBook to their "Depot" in Houston, TX for display replacement. I gave my MacBook to the Apple Store on a Wednesday afternoon, and it was returned that Friday. So, Apple shipped my MacBook overnight to Houston by FedEx, the display replaced the next day, and then returned via FedEx the same day of the repair. Super fast and excellent service. I was worried that the Depot repair would scratch or sloppily repair my MacBook, as it is in pristine condition. But my MacBook was returned in equally pristine condition with a new display assembly (the complete display replaced as it is a singular, bonded part).

For those MacBook owners who are curious which screen I had, and what was the replacement, I used the Color Sync app to find out the display information. The defective screen was model "0000A018" and the manufacturer was "00000610". The replacement display was also a model "0000A018" model, and also manufactured by "00000610". The manufacture date code for the replacement is "CCD71000", but I can"t seem to find the actual date translation through a Google search. I did remember that the manufacturer date code for the defective screen was different than the replacement, but I did not write it down. My research of manufacturer codes and model #s did not confirm if the screen was made by Samsung or LG. Anyway, the screen looks perfect right now, with no muras detected. As a side note, I take great care of my MacBook to ensure that it is always protected (in a case), and handled carefully. Some online forums stated that Apple Geniuses have told other MacBook Pro Retina owners that their particular muras were caused by pressure on the display (either by pressure on the aluminum exterior, or on the screen). I can say 100% that my mura was not caused by external pressure, nor excessive heat. And from my experience reporting the problem to Apple Support and the Apple Store Genius, I think Apple is conceding that display muras may actually be manufacturer defects, rather than caused by owner mishandling.

So in conclusion, if anyone finds out that their retina display has a mura/muras, Apple should replace the display without question as long as it"s in the 1 year warranty period, or 3 year Apple Care period. I"m not sure if Apple would replace the screen out of the warranty period, though. But I think if your MacBook is out of the warranty period, and you have a Genius take a look, they would recommend a "Depot repair". A Depot repair can only be initiated by an Apple Genius, or an AASP, and is a flat rate repair. The flat rate is $280 and will not only replace your display, but will repair and/or replace any parts needed. You may receive a new logic board, keyboard, battery, etc., if the Depot repair technician determines that your MacBook needs it to return it to refurbished condition. According to some other Apple forums, a Depot repair might restore your MacBook to a certified Apple Refurbished condition.

According to industry specifications, the diameter of a single defect spot on the screen must be less than 0.4 mm. The total number of defect spots must not exceed five. The diameter of a single spot must be less than 0.4 mm, and the distance between adjacent spots must be greater than 15 mm. In-warranty handling is not allowed in principle if the screen is considered to confirm with the standard.

If the screen defects exceed the specifications, back up your data and bring your device and proof of purchase to an authorized Huawei Customer Service Center for assistance.

Minute dots( bright dots and/or dark dots as seen above) may occur on a LCD. These dots are called Defective pixels (quoted from Wikipedia)". These dots may or may not stand out according to the colors displayed. It is a characteristic of LCDs and are not a defect and cannot be completely avoided with todays manufacturing technology.

Choosing a backlight system for LCD screen displays is a major consideration. It will determine a lot about your experience of the display and requirements during production. Different backlight options provide widely different effects in the contrast and brightness of the display. Also, depending on which backlight option you choose, it will affect some or all of the following: the cost of the overall product; how many products you will have to order due to manufacturing constraints; and how environmentally friendly the component parts are that make up the product.

The word LCD has been used to describe many display technologies. Often people believe that LCD screen displays are the same as a CRT (Cathode Ray Tube), an LED Display (Light Emitting Diode) or a Plasma display. This is not the case! Let’s discuss what an LCD is and what it is not.

Think of the liquid crystal display (LCD) as a window blind. Positioned in one direction the blinds allow light to pass through, or turned another direction they block the light. Just like a window blind, the LCD does not create its own light, it only blocks or allows it to pass through.

As you know, you can adjust the blinds to alter the amount of light desired. When fully closed, the blinds block light completely; when open, all light passes through; and when angled, partial light comes in. An LCD works similarly to this, with one significant enhancement: an LCD has the ability to block light in some areas and allow light to pass in other locations of the glass. An example of this is the display used on a gas pump. The customer sees numbers where the light is blocked, and a clear area where the light is allowed to pass through.

LCD’s are not CRT’s, LED’s, nor are they Plasma displays. Each of these types of displays produces their own light and are called emissive displays. Emissive displays require more power than an LCD.

Emissive displays have a distinct advantage in that they can be seen clearly at night whereas LCD’s cannot. However, the solution to this problem of low-light visibility is to install a backlight behind the LCD. Backlights do require more power than the LCD itself, but they can be turned on only when necessary. Many products that are powered by batteries will have the backlight dim or shut off after a certain amount of time. This can be seen on cell phones and watches. Consequently, even though a little more power is used for the backlight than used in a stand-alone LCD, because it is not constantly on, the LCD’s with backlights wind up using less power than their emissive display competitors. LCD screen displays using backlights become the clear choice.

This option is the most popular for products that have a lower power budget. Products that run on battery need to conserve power and the lowest powered backlight available is to have no backlight at all.

The Amazon Kindle is a perfect example. The Kindle makes use of a display technology called ‘e-paper’, which looks more like a printed page than any other device on the market currently. This specific e-book reader does not contain a backlight. Because it omits the backlight it can operate up to one month without recharging. Imagine, you could take it on a cruise to Fiji and back and never have to worry about recharging it!

Thinking back to your product, not all products can omit a backlight; in fact it may require one. If it does need a backlight the most popular option is an LED.

A light emitting Diode (LED) is a semiconductor that produces light when current is passed through the device. Light is created from the energy conversion that takes place in the LED die. The advantages of an LED are:LED lights are much more rugged and can handle shock much better than other types of lights.

LED backlights are made up of an array of LED’s. They come in a variety of colors including red, green, yellow, amber, blue, white and R/G/B (Red/Green/Blue). From the R/G/B trio any color in the rainbow can be made.

The majority of the LED backlight colors will operate with a half-life of 50K to 70K hours. (Remember, half-life is when the light will be half as bright as when it was first turned on. This is not when the LED will burn out.) Blue and white LED’s do have a shorter half-life than other colors. Presently, they are rated at 30K hours. That means that if you turned them on today and left them on, in 3.4 years they would be half as bright as they are today! One thing to take into account is that as technology improves, the lifetime of the LED’s will become longer, which will also increase the half-life. Below is a photo of a blue LED backlight.

To make LED’s display correctly, they are placed behind the LCD screen display in an array pattern. The challenge is that LED’s, similar to a light bulb, project a beam of light which can show spots of light. These spots are called hot spots. This can be an issue with LED’s since they will make the display look like it has polka dots. Below is a photo of a LED behind the LCD glass. This problem will be solved with the use of a diffuser.

A diffuser is like a lamp shade and is placed between the glass and the LED’s. The goal is to disperse the light or make it more even. Below is a photo of a diffuser. At the bottom of the diffuser you will see the LED’s. This is where you can see hot spots. But as the light travels further into the diffuser, the light becomes more even. The diffuser solves the issue with hot spots and makes LED’s a very attractive option.

EL (Electro Luminescent) backlights, also known as ELP’s (Electroluminescence Panel), have been used as a backlight for LCD’s for several years. They are available in a range of colors with white being the most popular. EL technology makes use of colored phosphors to generate light. They require AC (alternating current) rating of 100VAC @ 400Hz.

In the last three to four years, EL backlights have decreased in popularity. There are several reasons for this drop in popularity.The EL backlight requires an inverter to convert DC to AC. The cost of the inverter increases the cost of the overall LCD Display.

The half-life of an EL is an estimated 3,000 to 5,000 hours. (Once again, half-life is when the backlight is half as bright as when it was first turned on.)

LCD screen display manufacturers now require an MOQ (Minimum Order Quantity) of no less than 500 displays for orders that include EL backlights. This MOQ number is likely to increase in the future as this type of backlight becomes less popular. Additionally, as the demand drops the price will naturally increase.

A Cold Cathode Fluorescent Lamp (CCFL) is similar to the long fluorescent light bulbs you see in the ceilings of offices. Below are photos of various types.

This technology has been in use for many years, but in the last few years the popularity of this type of backlight has decreased. There are a few reasons why this is so.Similar to EL backlights, this technology operates on AC.

The majority of LCD screen display manufacturers no longer offer CCFL as an option. There are too many negatives and not enough positives to their use. The suppliers that do offer this now require a very high MOQ (Minimum Order Quantity).

When choosing the type of backlight for your LCD screen displays it is important to keep in mind MOQ’s and future availability. Make sure you are choosing a technology with a future so that your product has one too!

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.

A flat-screen TV bulb replacement costs between $60 to $120, with most homeowners spending $85 for parts and labor. The price for replacement bulbs ranges from $18 to $80.

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.

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.

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.

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.

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.

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.