Black Spot On Projector Screen? The 68 Correct Answer

Make sure the lens cover is fully open or removed.

Press the A/V Mute button on the remote control to see if the picture has been temporarily turned off.

button on the remote control to see if the picture has been temporarily turned off. Make sure all required cables are securely connected and the projector and attached video sources are turned on.

Press the projector’s power button to wake it up from standby or sleep mode. Also check if your connected computer is in sleep mode or showing a blank screen saver.

Press the menu button. If the projector menu can be displayed, there may be a problem with the connected video source, cable connection, or port.

Button. If the projector menu can be displayed, there may be a problem with the connected video source, cable connection, or port. Check the settings in the Signal menu to ensure they are correct for the current video source.

Adjust the brightness setting or select the Normal Power Consumption setting.

Setting or select the Power Consumption setting. Check the display setting to make sure News is set to On.

Setting to ensure that is set to . If the projector does not respond when you press the control panel buttons, the buttons may be locked. Unlock the keys.

If the projector does not respond when you press buttons on the remote control, make sure the remote control receivers are turned on.

For images projected using Windows Media Center, reduce the screen size in full screen mode.

Disable DirectX functions for images projected from applications using Windows DirectX.

If the other solutions do not solve the problem, reset all projector settings using the Reset menu options.

Menu. The projector may not be able to project copyright-protected videos that you play on a computer. See your computer manual for details.

If no image appears, try the following solutions:

A premium projection screen is the focal point of any home theater. The huge display dazzles with brilliant colors as it reflects the light from a projector. While a high-end screen can impress for years, like anything else in life, it needs cleaning.

Projector screens collect dust, and the oils on your hand (or your child’s hands) can stain them. And who hasn’t thrown popcorn at a terrible movie? A build up of dust and oil can affect reflectivity and overtime can leave permanent stains.

However, you can’t just toss a projection screen in a washing machine or scrub it with chemicals like you would a window. If you don’t clean it properly, you risk damaging your screen. So how do you properly clean a projector screen?

WARNING: Follow these instructions carefully for cleaning a projector screen, as not all screens use the same materials. Before you polish your screen, be sure to read the user guide to learn what to do and what not to do. If your screen was custom installed, speak to your home theater installer to ensure the material is not damaged.

1. Determine if the overhead transparency is damaged by viewing different slides on the overhead projector. If the shadow does not appear on other slides, you may need to replace the defective sheet.

2. Make sure there are no foreign objects between the table glass and the projection head. Also, make sure there are no objects between the projector and the screen.

3. Adjust the distance and focus of your overhead projector to make the image clearer and remove any shadows at the corners of the projection.

4. Clean the stage glass, all mirrors and projection lenses to remove any stains or debris.

5. Replace old projector bulbs when the lamp seems dim or the bulb has not been replaced for a long time.

A weird black dot is probably one of the most disheartening things you can come across when buying a new screen. That, dear readers, is a dead pixel. Here’s why they happen and what you can do about them.

What causes a dead pixel?

Before you dive headlong into dead pixel repair, it’s important to first understand how pixels work in a monitor. The primary technology that powers monitors is Liquid Crystal Display, or LCD for short.

How it works is that two polarizing filters sandwich a layer of liquid crystal, a name for a type of liquid that can also exhibit properties of crystals. Behind this sandwich is a backlight that provides the light source you see from your monitor. As that light goes through the sandwich, each layer is altered using electrons to produce either light, no light, or a gradient between the two. On an individual level, these are called electrodes and are the building block of LCD monitors.

If you want to get color out of your LCD, add another three layers of filters – usually red, green, and blue. Again, by adjusting the number of electrons going into each color of the filter, you can increase or decrease the hue and intensity, giving you a specific RGB value that your eyes interpret as color. Therefore, each pixel consists of three different electrodes, one for each color.

If you have a problem with a pixel, the underlying cause is that one or more electrodes for that pixel are somehow not working properly.

Types of dead pixels: Stuck, Hot and Dead

All right, so you know how pixels work and you have a dead pixel to deal with – but do you really have a dead pixel? There are various pixel issues that you might encounter. If you’re lucky, you won’t be dealing with a dead pixel.

For example, one of the most common errors is a “stuck pixel”. Luckily, there are a few things you can try to fix a stuck pixel.

Another defect is a “hot pixel”, i.e. a pixel that is always bright. That’s because the electrodes behind it let all light through, regardless of what’s on the screen. The opposite is called a dark dot defect, where no light passes through, although this defect is a little less common.

Finally we have the dead pixel and this one is the real killer because it means the electrodes behind the pixel have completely failed.

Can you fix a dead pixel?

Unfortunately for you as a consumer there is no direct way to fix a dead pixel as 99% of the time it is a manufacturing defect or shipping issue. At this point, your only option is to look at the warranty that comes with your screen and see if dead pixels are covered or not.

Ultimately, this can vary by manufacturer and screen class. For example, Class I monitors do not allow dead pixels, so the manufacturer will replace them with one in good condition.

On the other hand, Class III monitors allow up to 15 dead pixels and three clusters of stuck pixels. Unless your dead pixel problem is severe enough, your manufacturer’s warranty will not cover it.

Interestingly, manufacturers sometimes take these broken screens and sell them at a massively discounted price. It’s a great way to recycle the products for applications where dead or stuck pixels aren’t as much of a problem, e.g. B. in industrial processes or server rooms where the graphic quality is not essential.

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If you’ve noticed unusual specks on your display, you may be dealing with stuck or dead pixels. Fortunately, these pixels are usually harmless and can be detected with special pixel tests.

Let’s take a look at how to spot them and get rid of them.

How to identify dead or stuck pixels

Have you noticed black or solid dots on your screen? No matter what you do, they stay in place. They can be distracting and disruptive.

These dots are either stuck or dead pixels. You need to identify them so that you can find an appropriate solution.

Dead and stuck pixels can appear on all types of LCD screens. This includes monitors, phones and camera displays. However, it is easier to spot them on larger displays.

Don’t worry – in most cases these pixels are not a problem.

If you’re using a camera, look closely at your LCD display when taking a picture. Are there spots that stay in the same place no matter how much you move your camera? These spots are dead or stuck pixels.

You can also take a photo and zoom in to easily find stuck or dead pixels.

If you’re using a monitor, you can easily check for dead or stuck pixels using some websites.

The difference between stuck and dead pixels

There is a clear difference between stuck and dead pixels. If you are absolutely sure that the pixels on your screen are not dust, you need to identify them.

Stuck pixels are usually red, green, blue, or yellow. Dead pixels are black. No matter how much your screen changes, these pixels stay fixed in one place and don’t change color.

Keep in mind that stuck pixels can also be black or very dark. You could accidentally mistake them for dead pixels. To make sure they aren’t dead, you need to run a dead pixel test. More on that later.

Stuck pixels are much easier to remove than dead pixels. If you’re sure you have a dead pixel on your screen, you probably need to hire a specialist or replace your display.

Check for dead and stuck pixels with the LCD Dead Pixel Test or Bad Pixel Test

Here are a few simple websites to help you check for dead pixels using solid colors. They basically do the same thing, but one of them may be more compatible with your device/browser than the other:

You must be in full screen mode. Make sure to wipe down your screen beforehand so you don’t accidentally mistake a speck of dust for a dead pixel!

Click on each color. If you don’t notice any unusual dots (black or another color) on your screen, you probably don’t have a dead or stuck pixel problem.

Use pixel checker apps to detect stuck or dead pixels

You can use the above websites to check for stuck pixels on your phone. However, if you want something more mobile-friendly, try this app:

Don’t rub your screen to get rid of dead pixels

Some users recommend rubbing a dead pixel with a cloth to get rid of it. This may work temporarily, but will damage your display in the long run.

Too much rubbing can damage even more pixels on your screen and cause serious problems. If none of the solutions work, it is best to contact a specialist.

Useful tips to get rid of stuck or dead pixels

There are several ways to remove stuck or dead pixels.

As previously mentioned, dead pixels cannot usually be removed without professional help. However, you need to make sure those dead pixels aren’t secretly stuck pixels or just dust particles.

Restart your device

This is a very simple and seemingly straightforward method, but it might be the best solution to your problem. If your screen appears faulty, it may simply need to be refreshed.

You can refresh the page you are working on or restart your device. If the problem persists, continue to the next tips.

Gently wipe your screen with a screen-friendly cloth

Our eyes can sometimes play tricks on us. What looks like an ominous dead pixel may actually be a harmless blemish.

Use a screen cleaning spray and cloth to wipe down your display. Be careful not to apply too much pressure or you could damage your screen. A few gentle swipes might fix the problem.

Use JScreenFix to remove stuck pixels

If the above options don’t work, JScreenFix might be the best solution. This is a website that anyone can use for free. You don’t need to download any programs or extensions to use it. Best of all, it promises to remove stuck pixels in less than 10 minutes.

JScreenFix fixes stuck pixels. If you think you have a dead pixel, you can also try this method. For this to work effectively, you need to know where exactly your stuck pixels are.

When you start the program, you will see a black screen with a box. The box should be filled with tiny specks of moving grain.

Your task is to find the stuck pixel and drag the box there. Leave it there for a few minutes. This should remove any abnormal pixels on your display.

Frequently asked questions about stuck and dead pixels

Can I fix dead pixels?

If you’re sure the pixel is dead (and not stuck), you need to see a specialist. There are a few dead pixel repair methods, but most of them don’t seem to work effectively.

However, in some cases, dead pixels are actually stuck pixels.

Are stuck pixels permanent?

no In most cases, stuck pixels are temporary. You may need to try some methods to remove them. There are a few programs that promise to easily remove stuck pixels.

Is a white pixel dead or stuck?

White pixels are stuck pixels. Dead pixels are usually black. Any other color means your pixel is just stuck.

Do dead pixels spread?

Dead pixels don’t usually spread. They are usually a small flaw in a display. If they spread, you may need to hire a specialist or replace your screen.

Conclusion

Stuck and dead pixels might be different, but they’re equally distracting to a photographer.

Make sure you clean your display, run a dead pixel test, and use JScreenFix to get rid of the pixels. It is likely that this will fix the problem and stop you from seeing a specialist.

For more great tips, check out our articles on optical vs digital zoom next, or using visual metaphors in your photography!

Spotted a black spot on your liquid crystal display (LCD)? Whether it’s on the top, bottom, or side, it’s likely to stick out like a thumb. When you turn on the LCD, the black spot is probably the first thing you see. However, by understanding what causes black spots on LCDs, you can take the necessary precautions to prevent them from occurring.

Superficial dirt or deposits

Black spots are often caused by nothing more than surface dirt or debris. Over time, dirt and debris accumulate on the surface of LCDs. If this option is not checked, this dirt or debris may manifest itself as one or more black spots. The black spots do not affect the performance of an LCD nor damage the internal circuitry of the LCD. Nonetheless, it’s a good idea to clean the screen of your LCD when surface dirt or debris is causing a black spot.

You can clean the screen of your LCD with a damp – not soaked – lint-free microfiber cloth. With the LCD off, gently rub the microfiber cloth across the screen until the black spot is gone.

Stuck Pixel

Another common cause of black spots on LCDs is a stuck pixel. As the name suggests, a stuck pixel is a pixel on an LCD — or other display device — that cannot change color. Pixels are designed to change color depending on the image displayed on the screen. If a pixel does not change color, it is considered a stuck pixel.

Dead Pixel

Not to be confused with a stuck pixel, a dead pixel can also cause black spots on an LCD. What exactly is the difference between a stuck pixel and a dead pixel? A stuck pixel is illuminated when the LCD is turned on; it just doesn’t change color. A dead pixel, on the other hand, is not eliminated. In other words, dead pixels have all three sub-pixels – red, green, and blue – permanently off. And since they’re not backlit, dead pixels look like black dots on screen.

Finally

As a reminder, black spots on LCDs are usually caused by either surface dirt or debris, a stuck pixel, or a dead pixel. Of course, the easiest problem to fix is ​​a surface dirt or grime. In comparison, stuck pixels are a bit harder to fix, while dead pixels are the hardest to fix. If a stuck pixel is creating a black spot on your LCD, you may be able to use a third-party flash tool to restore it.

set of chipsets

“DLP projector” redirects here. For other projection devices, see film projector

logo

The Christie Mirage 5000, a 2001 DLP projector

Digital Light Processing (DLP) is a series of chipsets based on optical microelectromechanical technology, using a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments. While Texas Instruments invented the DLP imaging device, the first DLP-based projector was invented by Digital Projection Ltd. in 1997. introduced. Digital Projection and Texas Instruments both received 1998 Emmy Awards for DLP projector technology. DLP is used in a variety of display applications, from traditional static displays to interactive displays, as well as non-traditional embedded applications, including medical, security, and industrial applications.

DLP technology is used in DLP front projectors (standalone projection units primarily for classrooms and businesses), DLP rear projection televisions, and digital signs. It is also used in about 85% of digital cinema projection and in additive manufacturing as a light source in some printers to cure resins into solid 3D objects.[1]

Smaller ″pico″ chipsets are used in mobile devices, including cellular phone accessories and projection display functions embedded directly into phones.

Digital Micromirror Device[ edit ]

Diagram of a digital micromirror showing the mirror mounted on the suspended yoke, with the torsion spring running from bottom left to top right (light gray), with the memory cell electrostatic pads below (top left and bottom right)

With DLP projectors, the image is generated by microscopic mirrors arranged in a matrix on a semiconductor chip, a so-called Digital Micromirror Device (DMD). These mirrors are so small that the DMD pixel pitch can be 5.4 µm or less.[2] Each mirror represents one or more pixels in the projected image. The number of mirrors corresponds to the resolution of the projected image (often half as many mirrors as the advertised resolution due to wobulation). 800×600, 1024×768, 1280×720, and 1920×1080 (HDTV) matrices are some common DMD sizes. These mirrors can be quickly repositioned to reflect light either through the lens or onto a heat sink (called a light trap in Barco terminology).

Rapidly toggling the mirror between these two orientations (essentially on and off) creates shades of gray controlled by the ratio of on-time to off-time.

Color in DLP projection [ edit ]

There are two main ways that DLP projection systems produce a color image: that of single-chip DLP projectors and that of three-chip projectors. A third method, tri-color light emitting diode sequential lighting, is being developed and is currently used in televisions manufactured by Samsung.

Single chip projectors [ edit ]

Inside view of a single chip DLP projector showing the light path. Light from the lamp enters an inverted fisheye, passes through the spinning color wheel, crosses under the main lens, reflects off a mirror on the front and spreads onto the DMD (red arrows). From there, light either enters the lens (yellow) or reflects off the top cover down into a light sink (blue arrows) to absorb unneeded light. The top row shows the overall components, close-ups of the 4-segment RGBW color wheel and the light sink diffuser/reflection plate on the top cover.

In a projector with a single DLP chip, colors are generated either by connecting a color wheel between a white lamp and the DLP chip, or by using individual light sources, such as LEDs or lasers, to generate the primary colors. The color wheel is divided into several sectors: the primary additive colors: red, green and blue, and in many cases white (clear). Newer systems replace white with the subtractive primary colors cyan, magenta and yellow. The use of the subtractive colors is part of the newer color performance system called BrilliantColor, which processes the additive colors together with the subtractive colors to produce a wider range of possible color combinations on screen.

The DLP chip is synchronized with the rotation of the color wheel so that when the green section of the color wheel is in front of the lamp, the amount of green is displayed on the DMD. The same applies to the red, blue and other sections. The colors are thus displayed sequentially at a sufficiently high rate that the viewer sees a “full color” composite image. On early models, this was one rotation per frame. Today, most systems work with up to 10 times the frame rate.

The black level of a single-chip DLP depends on how unused light is disposed of. As the unused light is scattered to reflect and diffuse off the rough inner walls of the DMD/lens chamber, this scattered light becomes visible as a faint gray on the projection screen when the image is completely dark. Deeper blacks and higher contrast ratios are possible by directing unused HID light away from the DMD/lens chamber into a separate area for extraction and shielding the light path from unwanted internal secondary reflections.

The “rainbow effect” color wheel [ edit ]

The rainbow effect found on DLP projectors that use a mechanical spinning wheel.

DLP projectors that use a mechanically spinning color wheel can exhibit an anomaly known as the “rainbow effect”. This is best described as brief flashes of perceived red, blue, and green “shadows” most commonly observed when the projected content features high-contrast areas of moving light or white objects on a mostly dark or black background. Common examples are the scrolling credits of many films and also animations with moving objects surrounded by a thick black border. A brief visible separation of colors may also be apparent when the viewer’s gaze is moved rapidly across the projected image. Some people notice these rainbow artifacts frequently, while others may not see them at all.

This effect is caused by how the eye follows a moving object on the projection. When an object moves on the screen, the eye follows the object with a constant movement, but the projector displays each alternating color of the frame in the same place for the duration of the entire frame. So as the eye moves, it sees a frame of a certain color (e.g. red). If the next color then appears (e.g. green) even though it appears in the same spot that the previous color overlaps, the eye has moved towards the object’s next frame target. Thus, the eye sees that particular frame color shifted slightly. Then the third color is displayed (e.g. blue) and the eye sees the color of this frame slightly shifted again. This effect is not only perceived for the moving object, but for the whole picture. Multicolor LED-based and single-chip laser-based projectors are able to eliminate the spinning wheel and minimize the rainbow effect because the pulse rates of LEDs and lasers are not limited by physical motion. Three-chip DLP projectors work without color wheels and therefore do not show this rainbow artifact.”[3]

Three-chip projectors [ edit ]

A three-chip DLP projector uses a prism to split the light from the lamp, and each primary color of light is then sent to its own DMD chip, then recombined and passed through the lens. Three-chip systems are found in high-end home theater projectors, large venue projectors, and DLP cinema projection systems found in digital cinemas.

According to DLP.com, the three-chip projectors used in movie theaters can produce 35 trillion colors. The human eye should be able to recognize around 16 million colors, which is theoretically possible with a single-chip solution. However, this high level of color precision does not mean that three-chip DLP projectors are capable of displaying the entire gamut of colors that we can distinguish (this is fundamentally impossible with any system that composes colors by adding three constant primary colors). On the other hand, one-chip DLP projectors have the advantage that they allow any number of primary colors in a sufficiently fast color filter wheel and thus the possibility of improved color scales is available.

light source [ edit ]

The InFocus IN34, a DLP projector

DLP technology is light source independent, so it can be used effectively with a wide variety of light sources. Historically, the primary light source used in DLP display systems was a replaceable high-pressure xenon arc lamp assembly (containing a quartz arc tube, reflector, electrical connectors, and sometimes a quartz/glass shield), while most pico (ultra- small) DLP projectors use high-power LEDs or lasers as the illumination source. Since 2021, a laser light source has become very common in many professional projectors, such as the Panasonic PT-RZ990.[4]

Xenon arc lamps [ edit ]

Xenon arc lamps use a constant current supply that starts with a high enough open circuit voltage (between 5 and 20 kV depending on the lamp) to strike an arc between the electrodes, and once the arc is established the voltage across the lamp drops a certain value (typically 20 to 50 volts[5]) while the current increases to a level required to keep the arc at optimal brightness. As the lamp ages, its efficiency decreases due to electrode wear, resulting in a reduction in visible light and an increase in waste heat. End of lamp life is usually indicated by an LED on the unit or a text warning on the screen necessitating replacement of the lamp assembly.

Continued operation of the lamp beyond its rated life may result in a further reduction in efficiency, the light beam may become uneven, and the lamp may eventually become so hot that the power cords can melt from the lamp terminals. At some point, the required starting voltage also increases to such an extent that ignition can no longer take place. Secondary protections such as a thermal protector can shut down the projector, but even a thermally overstressed quartz arc tube can rupture or explode. Virtually all lamp housings contain heat-resistant barriers (in addition to those on the lamp unit itself) to prevent the red-hot quartz fragments from escaping the area.

LED-based DLPs [ edit ]

The first commercially available LED-based DLP HDTV was the Samsung HL-S5679W in 2006, which also eliminated the use of a color wheel. In addition to long life, which eliminates the need for lamp replacement, and the elimination of the color wheel, other advantages of LED lighting include instant operation and improved color with increased color saturation and improved color gamut to over 140% of the NTSC color space. In 2007, Samsung expanded the LED model range with products that are available in screen sizes of 50, 56 and 61 inches. In 2008, the third generation of Samsung’s LED DLP products was available in screen sizes of 61 inches (HL61A750) and 67 inches (HL67A750).

Traditional LED technology does not produce the intensity and high luminous efficacy needed to replace arc lamps. The special patented LEDs used in all Samsung DLP TVs are PhlatLight LEDs designed and manufactured by Luminus Devices based in the USA. A single RGB PhlatLight LED chipset illuminates these projection TVs. The PhlatLight LEDs are also used in a new class of ultra-compact DLP front projectors, commonly referred to as “pocket projectors”, and have been featured in new models from LG Electronics (HS101), Samsung Electronics (SP-P400) and Casio (XJ- A series). Home theater projectors will be the next category of DLP projectors that will use PhlatLight LED technology. At InfoComm in June 2008, Luminus and TI announced their collaboration in applying their technology to home theater and business projectors, demonstrating a prototype LED-based PhlatLight DLP home theater front projector. They also announced that products from Optoma and other companies to be named later in the year will be available later in 2008.

Luminus Devices PhlatLight LEDs were also used by Christie Digital in their DLP-based MicroTiles display system.[6] It is a modular system consisting of small (20″ diagonal) rear projection cubes that can be stacked and tiled together to form large display screens with very small seams. The scale and shape of the display can be any size limited only by practical limits.

Laser-based DLPs[ edit ]

The first commercially available laser-based DLP HDTV was the Mitsubishi L65-A90 LaserVue in 2008, which also eliminated the use of a color wheel. Three separate color lasers illuminate the digital micro-mirror device (DMD) in these projection televisions, producing a richer, more vibrant palette of colors than other methods. See the Laser Video Display article for more information.

Digital Cinema[edit]

DLP CINEMA. A technology from Texas Instruments

Texas Instruments, DLP Cinema Prototype Projector, Mark V, 2000

The NEC Cinema DLP projector in 2006

DLP Cinema systems have been used and tested commercially in cinemas since 1999. In June 1999, Star Wars: Episode I – The Phantom Menace became the first film to be fully scanned and distributed to theaters. Four theaters installed digital projectors for the film’s release. The same happened in the same year for the animated film Tarzan. Later that year, Toy Story 2 became the first film to be created, edited and distributed entirely digitally, with more theaters installing digital projectors for its release. DLP Cinema was the first commercial digital cinema technology and is the leading digital cinema technology with a global market share of approximately 85% (as of December 2011). Digital cinema has some advantages over film, as film can be subject to color fading, cracking, scratches, and dirt build-up. Digital cinema allows film content to remain of consistent quality over time. Today, most film content is also captured digitally. The first fully digital live-action feature film shot without film was the 2002 release, Star Wars Episode II: Attack of the Clones.

DLP Cinema does not manufacture the end projectors but supplies the projection technology and works closely with Barco, Christie Digital and NEC who manufacture the end projection units. DLP Cinema is available to theater owners in multiple resolutions based on exhibitor needs. These include 2K – for most cinema screens, 4K – for large cinema screens, and S2K, specifically designed for small cinemas, particularly in emerging markets worldwide.

On February 2, 2000, Philippe Binant, technical manager of the Digital Cinema Project at Gaumont in France, realized the first digital cinema projection in Europe[7] using the DLP CINEMA technology developed by Texas Instruments. DLP is the current market leader in professional digital film projection,[8] primarily because of its high contrast ratio and available resolution compared to other digital front projection technologies. As of December 2008, over 6,000 DLP-based digital cinema systems have been installed worldwide.[9]

DLP projectors are also used in RealD theaters and newer IMAX theaters for 3D movies.

Vendor and Marketplace[edit]

56 inch DLP rear projection TV

Since its commercial introduction in 1996, DLP technology has rapidly gained market share in the front projection market and now holds more than 50% of the world share of front projection in addition to 85% market share in digital cinema worldwide. In addition, DLP technology holds about 70% market share in the pico (small, mobile display) category. Over 30 manufacturers use the DLP chipset to power their projection display systems.

Benefits[edit]

Smooth (at 1080p resolution), shake-free images.

Perfect geometry and excellent greyscale linearity achievable.

Usually excellent ANSI contrast.

Using a replaceable light source means potentially longer lifespan than CRTs and plasma screens (this can also be a disadvantage as detailed below).

The light source is more easily replaceable than the backlights used in LCDs and is often user replaceable in DLPs.

The light of the projected image is not inherently polarized.

New LED and laser DLP display systems make lamp replacement more or less unnecessary.

DLP offers affordable 3D projection display from a single unit and can be used with both active and passive 3D solutions.

Lighter weight than LCD and plasma TVs.

Unlike their LCD and plasma counterparts, DLP screens do not rely on liquids as a projection medium and are therefore not limited in size by their inherent mirror mechanisms, making them ideal for increasingly larger HD theater and event screens.

DLP projectors can handle up to seven separate colors, giving them a wider color gamut.

Disadvantages[edit]

The back of a Mitsubishi XD300U shows the available output and input jacks.

Some viewers are bothered by the “rainbow effect” present on color wheel models – particularly older models (see above). This can be easily observed by using a camera’s digital viewfinder on projected content.

Rear-projection DLP televisions are not as thin as LCD or plasma flat panels (although roughly comparable in weight), although some 2008-up models can be wall-mounted (while still being 10 to 14 inches [250 to 360 mm] thick are ) [10]

Lamp/bulb replacement in lamp based units. The lifespan of an arc lamp averages 2000-5000 hours and the replacement cost ranges from $99 to $350 depending on the make and model. Newer generation sets use LEDs or lasers, which effectively eliminate this problem, although replacement LED chips could potentially be needed over the longer life of the TV.

Some viewers find the high-pitched whistling of the color wheel distracting. [11][12][13] However, the drive system can be designed to be quiet, and some projectors do not produce audible color wheel noise.

However, the drive system can be designed to be quiet, and some projectors do not produce audible color wheel noise. Dithering noise can be noticeable, especially in dark areas of the image. Newer (after ~2004) chip generations have less noise than older ones.

Error diffusion artifacts caused by averaging a hue across different pixels, since one pixel cannot accurately represent the hue

Response time in video games can be affected by upscaling lag. While all HDTVs exhibit some lag when upscaling lower resolution inputs to their native resolution, DLPs are commonly reported to exhibit longer lags. Newer consoles with HD output signals don’t have this problem as long as they are connected with HD capable cables. [14]

Reduced viewing angle compared to direct view technologies such as CRT, plasma and LCD

Can use more electricity and generate more heat than competing technologies.

DLP, LCD and LCoS rear projection[ edit ]

The closest competing system to DLP is known as LCoS (Liquid Crystal on Silicon), which creates images using a stationary mirror mounted on the surface of a chip and uses a liquid crystal matrix (similar to a liquid crystal display) to control how much Light is reflected.[15] DLP-based television systems are also arguably considered less in-depth than traditional projection television.

See also[edit]

References[edit]

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You’ve finally made the jump from a wall-mounted TV to a slick new projector, but now dust particles are starting to cling to your lens and you can’t see every pore on the gladiator’s face as clearly as you used to. Well, you can’t just use any household cleaner to bring your projector lens back to its glory days, so here’s a quick and easy guide on how to restore every possible detail from Russel Crowe.

So how do you clean your projector lens?

Make sure the projector is turned off and let it cool down for at least 20 minutes. Use a can of compressed air or a manual lens blower to blow away any debris that has built up on the lens. Remember to hold the can of compressed air upright and spray in short bursts to avoid damaging the glass. Lens brushes are specially designed to clean camera and projector lenses without damaging them. Simply brush the lens in a circular motion to remove dust and dirt. Either use disposable lens wipes or spray lens cleaner onto a microfiber cloth and gently wipe the lens in a circular motion.

Things to consider when cleaning a projector lens

Keeping your projector lens clean can greatly improve picture quality, but you don’t want to use the wrong products and cleaning methods that can damage the glass or electronics inside, the same principle applies to other electronics including TV screens (as we explained earlier).

Things to do when cleaning a lens

• Always wipe the lens in a circular motion from the center outwards. If you wipe the same area more than once, simply spread the dirt around the glass.

• Always use products specifically labeled for lens cleaning.

• Always keep your cleaning products like your microfiber cloths and lens brushes in safe places where they stay clean. A dirty lens brush is basically useless.

• Always spray the air tank in short bursts to avoid damaging the glass.

Things to avoid when cleaning a lens

• Never use a t-shirt to clean your lens, it will scratch the glass no matter how soft it is.

• Never use your breath to wipe the lens, the acid from your breath can damage the coating on the glass, you basically spit all over it, and lens wipers are so much cheaper than new projectors.

• Never touch the glass with your fingers. Fingerprints are by far the most difficult to remove and the most detrimental to image quality.

• Never use glass cleaners or other household products that are not specifically labeled for cleaning your projector lens. The wrong cloths or chemicals can irreversibly damage the lens.

• Never touch the bristles of your lens brush as this will leave oils from your skin on the bristles and then smear that oil onto your lens the next time you clean it.

How often should I clean my projector lens?

The difficult thing about cleaning your projector lens is: you can do it too much. For the most part, unless you’re projecting performances by Jaws on the beach or Lawrence of Arabia in the desert, your projector should stay fairly clean. A light amount of dust won’t really prevent you from seeing every detail.

Here’s a great lens cleaning kit (on Amazon) that you can use to clean your projector’s lens.

How often should you clean it then? It seems obvious, but the answer is: whenever it’s dirty. If you haven’t noticed a drop in video quality, there’s no reason to clean the lens.

Think of it this way: every time you clean the glass, you risk damaging it. The more you clean that glass, the more chances you have of accidentally scratching it. The most important thing is that it doesn’t get dirty in the first place.

Note: However, it is recommended to clean the projector air filters from dust every 3-4 months to avoid overheating.

How to prevent dust from getting on a projector lens

There’s really only one surefire way to keep dust from getting on your projector lens, and that is to use the lens cap when you’re not using the projector.

Get out of your house for a week’s vacation and see how much dust your electronics have accumulated. The longer your projector glass is exposed, the more dust and dirt it collects. It is really that easy.

You also need to consider the placement of your projector in the room and make sure it’s not near an exhaust vent or fan that blows dust and debris onto the lens.

If you’re projecting things on the go instead of powering your home theater, you need to seriously consider how you store and transport the projector. Using the original packaging is an option, but you really don’t want it sitting around literally collecting dust.

How badly does dust affect the image quality of the projector?

It actually depends on whether you have an LCD or DLP projector system. LCDs are the more common, lower-cost home projectors. LCDs are less affected by dust when it comes to picture quality.

Dust simply collects on the lens and smears the image. With LCDs, the greater risk is that dust can collect in the ventilation openings and cause damage to the bulb and electronics inside through overheating

DLP projectors are the higher quality and more expensive projectors. Most cinemas use DLP projectors, but they are more prone to image problems caused by dust.

Dust can actually build up on the internal chips of a DLP projector and cause your picture quality to become grainy and splotches of the wrong color on the image – especially in the blacks of your image. To fix this problem you actually have to open the projector, remove the chips and clean them, but that’s another topic.

Conclusion

Cleaning your projector lens is a simple and inexpensive process that, if done correctly, will restore your projector to the picture quality it was when it was out of the box. Remember, the best thing you can do is prevent it from getting dirty in the first place. So put on the lens cap when you’re not using it and enjoy your Gladiator performances in full HD glory.

Warning: Do not use lens cleaner that contains flammable gases. The high heat generated by the projector lamp can cause a fire.

Caution:

Do not use glass cleaner or sharp materials to clean the lens, and do not subject the lens to physical impact; You can damage it. Do not use canned compressed air or the gases may leave residue. Avoid touching the lens with bare hands to avoid fingerprints or damage to the lens surface.