How Digital Light Processing Projectors Work
What is a DLP Projector?
Digital Light Processing is referred to as DLP. Light is projected through a layer of color wheels and reflection mirrors, then finally through a lens in a DLP projector. DLP projectors are distinguished from LCD projectors by their DMD chip, which was developed by Texas Instruments®.
Read more on DLP vs LCD.
DMD-Chips
There are about the same number of mirrors on each DLP chip as there are red blood cells. An image is created by manipulating light through these mirrors (magnified above). Microscopically tiny suspension hinges must change mirror positions at incredible speeds. A maximum of 16 million cycles per second can be achieved.
Video source data is reflected by each mirror to create an image. As long as the mirror is “On,” light is reflected toward the screen, which creates a visible pixel. As soon as mirrors are turned to the “Off” position, they reflect light away from the projection lens. Screens are prevented from being illuminated by this method.
Read more on How projectors work
How-a-DLP-Projector-Works-on-the-Inside
Color wheels are commonly used in DLP projectors. During the display, the wheel spins rapidly before the light source to produce RGB patterns. Cinema-like image quality is achieved through the use of DLP projectors. An in-depth understanding of the human eye lies at the core of DLP technology.
Red, blue, and green light are combined by the retina every 1/50th of a second to create an image. Red light is emitted by a DLP projector, followed by blue light, then green light. A distinct image is seen by the human eye due to the speed at which it happens.
Instead of seeing pulsating shades of RGB light, what you’re seeing is pulsating shades of RGB light. Your brain assembles the complete image so quickly because the alternating pattern happens so quickly. Slowing time would prevent you from seeing the full image. Rather than sequential images of red, green, and blue light, a series of consecutive images would appear!
Components
Lamp
Condensing lens
Colour Filter
Shaping Lens
DMD (digital micromirror device)
Working of the Projector
Lamp :
A current-regulating ballast ignites an arc between two electrodes in the quartz tube of a Xenon arc lamp by sending a pulse of 5000 – 20,000 volts.
Condensing Lens :
On the color wheel, light is converged by the condensing lens.
Colour Wheel :
It’s time to get a better understanding of this color wheel. It is easy to see from the diagram above that the screen receives light from a chip (DMD) which is located within the chip. All that the chip is capable of doing is either sending or not sending light – making it only capable of sending black and white signals. A color wheel is included in most projectors as an element that spins in synchronization over the DLP chip to create color images. DLP chips are capable of detecting the correct pattern of light for the various colors, as they rotate between red, blue, and green.
To keep track of all the images on the screen so quickly, the brain combines them into one image in full color, because the images go on and off so quickly. A phenomenon known as Persistence describes how it gives us a sense of a continuous moving picture going on at the moment.
DMD Chip :
The light falls on the DMD chip after passing through the color wheel. As the name DMD suggests, it is a chip that has several hundred thousand microscopic mirrors arranged on its surface. These mirrors are arranged in a rectangular array corresponding to each pixel in the image to be displayed. It is possible to turn the mirrors individually between the on and off states by rotating them approximately 10%-12°. When the projector is on, light is reflected from the bulb into the lens, creating a bright image on the screen to represent the pixels. As the light is directed elsewhere when it is off (most commonly onto a heatsink), it appears darker because the light is focused elsewhere.
Working on the DMD chip
Mechanical, electrical, and optical engineering are all applied to the working mechanisms of a DMD chip.
DMD chip
Thousands of tiny mirrors cover the DMD chip. Before any of the mirrors in the DMD chip switch to their on or off positions, the chip will rapidly decode a bit-streamed image code that enters through the semiconductor. For the picture to fade in, the data is converted from interlaced to progressive. Afterward, the chip adjusts display settings such as brightness, sharpness, and color quality to fit the screen. In 16 microseconds, the entire process is completed by relaying all the information to the mirrors.
As often as 5,000 times per second, the mirrors tilt up to +/- 12° toward or away from the light source (ON/OFF), depending on the tilt angle. The light gray pixels are created by switching on a mirror more than it is turned off. A dark gray pixel will be produced when a mirror is off more often than it is on. Now we can produce all the colors we want by combining the color wheel with this formula. A mirror’s intensity is determined by the percentage of time it is turned on in relation to the color wheel’s intensity.
Lens
As a result, we obtain the desired visual output on screen after all the data (pixels) obtained from the DMD chip are projected on the screen.
What to Look for in a DLP Projector: Standard Specs
Projectors with DLP technology offer a wide range of features and prices. It is appropriate to combine different combinations depending on the application.
There are many different uses for portable presentations, including home entertainment and worship places. Collaboration classrooms to conference rooms. Choosing the right projector will depend on how you intend to use it.
Resolution
Take a look back at the DLP chip with its incredible mirrors. One pixel is created by each mirror. Depending on the screen resolution, there are a certain number of mirrors. There are approximately 2.2 million mirrors in a 2K DLP projector, for example. The number of 4K devices is about 8.8 million. An image with a higher resolution will have better quality.
In this image, the image might appear differently depending on the resolution (or scheme) and may not be an image shown on the actual product.
It’s going to be a big year for a 4K DLP projection. XPR and DLP® 4K Ultra HD technologies make 4K projectors ideal for home theaters. Their 4K UHD resolution (3840 x 2160) generates 8.3 million distinct pixels.
Some projectors claim to “support” 4K when comparing them. The ability to reproduce 4K images is different from the ability to replicate actual 4K images. For a projector to qualify for true UHD projection, its active pixels must reach the Consumer Technology Association (CTA) requirement of 8 million pixels.
Contrast Ratio
The contrast ratio determines how dark a projector can make a picture and how light it can be. Picture quality is improved by a high contrast ratio. There is a range of contrast ratios available for DLP projectors, ranging from 500:1 to 100,000:1.
Projectors used in home theaters and high-end environments need a high contrast ratio. You should look for a contrast ratio between 10,000:1 and 100,000:1 when choosing a projector for your home theater. There is nothing better than bigger. Choose the highest aspect ratio for large venues, such as auditoriums: 100,000:1.
Contrast-ratio
In classrooms and conference rooms, having a high contrast ratio is less of a concern, since the benefits are most evident in semi-dark, pitch-black rooms with controlled lighting. The contrast ratio for business and classroom displays should be 4,000:1 – 30,000:1. High constrast ratio makes the DLP be used in the best LED projectors for Christmas.
Brightness
Light output by a projector is measured in lumens or lumens per square meter. Generally, the brighter the projector, the more lumens it has. There is an important distinction between bright and good. The brightest projector does not always produce the best results in every environment. There is also a cost associated with higher brightness.
Brightness needs are influenced by factors such as:
Lighting in the ambient environment. It is necessary to have a high level of brightness in viewing spaces with an abundance of lighting to ensure a sharp, clear image. The results are best when the brightness is low (but the contrast ratio is high), like in a home theater. Spaces that serve a variety of purposes benefit from mid-range brightness, between 2,000 and 4,000 lumens.
The size of the room or screen. Images need to be brighter in larger rooms and on larger screens. If you want a bright projector, you will need a projector with a high light distribution over an area. To determine how comfortable a viewing experience is, consider how many people are in the room. It is generally recommended that the screen size be larger if there are more people in the room.
Projector-Brightness
Following is a list of projectors categorized according to their ANSI lumen output:
Under 3,000 lumens – This projector is used in environments with low ambient light. The ideal application is for home theaters. Check our list of best projectors for home theater.
3,000 – 4,000 lumens
The DLP projectors in this price range are the best on the market, both in terms of value and features. Classrooms, conference rooms, and entertainment rooms in your home can usually be set to these brightness levels when it’s not possible to block out ambient light.
4,000+ lumens
Large meeting rooms, classrooms, and multipurpose rooms will benefit from projectors at this brightness level. Despite the larger screen size, these DLP projectors produce a crisp, clear image. Having a larger audience size makes viewing easier. An installation using a high-end projector with a brightness rating of over 4,000 lumens is considered a high-end installation. Such projects are the most suitable for outdoor uses.
What is the Rainbow Effect on DLP projectors?
The DLP Rainbow Effect occurs when the viewer watches a single-chip DLP projector with a color wheel and feels as if they saw flashes of red, green, and blue light while watching or even after stopping watching the DLP projector picture. Known as the Rainbow Effect, these flashes of vivid color create an illusion of depth. As the video image is shown in quick succession, the rainbow effect is caused by the single DLP projector showing the Red, Green, and Blue portions separately.
Some people experience the Rainbow Effect because their brains process these rapidly changing RGB sequences as one as a result of persistent vision. DLP projectors that produce the Rainbow Effect do not appeal to the majority of people.
Unlike single-chip DLP projectors that use a color wheel, DLP projectors with single-chip LEDs and hybrids don’t seem to suffer from this issue.
Read more on the best ultra short throw 4K projectors.
Different kinds of DLP projectors
Depending on how many DLP DMD chips it contains, DLP projectors can be divided into two types. There are two types of DLP projectors: single chip and three-chip. Single chip DLP projectors produce sharp images. A three-chip DLP projector is extremely expensive and is commonly used in cinemas. Furthermore, some DLP projectors have LEDs or lasers instead of ordinary lamps as the light source. The number of pixels or micromirrors on the DLP DMD is another subdivision of DLP projectors. By 2020, there will be two main models of DLP technology, either full HD or UHD 4K.
With a DLP projector, white light is split from the source lamp into its component colors Red Green, and Blue (RGB), and the red, green, and blue colors are delivered by a color wheel or colored LEDs and lasers. To reflect the right color from the color wheel to the screen, the DLP chip’s timing needs to be perfectly synchronized with the color wheel’s timing.
4K DLP chips for Projectors
As of now, Texas Instruments (TI) is the only American company that manufactures DLP chips for projectors.In 2020, there are very few 3 chip DLP home projectors or even native 4K home projectors on the market.A single DLP chip is now used in almost all DLP projectors.TI’s XPR pixel shifting technology will produce on-screen true 4K pictures with as many as 8.3 million pixels from a full HD single-chip DLP projector in 2020. The single-chip DLP has come a long way, and in 2020 the new trend for home projectors is to use it to produce actual 4K pictures.
Single Chip DLP DMDs are available from TI in three models. DLP660TE, DLP470TE, and DLP470TP are the three DLP® 4K UHD DMD chips from Texas Instruments. Having a diagonal size of 0.66 inches and a frame rate of 120Hz, the 4K DLP chip DLP660TE has a diagonal size of 0.66 inches. In terms of diagonal size, the 4K DLP chip DLP470TE has a 0.47-inch diagonal, while the DLP470TP has only a 0.47-inch diagonal and a 120Hz frame rate. In high-end DLP projectors, the chip measures 0.66 inches, whereas, in lower-end ones, it measures 0.47 inches.
While all of these 4K DLP chips have an on-screen resolution of 3840×2160 or full 4K UHD, their native resolutions are only 1920×1080. By using the Pixel shifting technology known as XPR from TI, they achieve the 4K resolution with 8.3 million pixels.
What is Color Brightness and White Brightness mean: How Digital Light Processing Projectors Work
It usually refers to the brightness of the UHP Mercury Arc Lamp, which is the light source of the projector. Lumens are generally reported by projector manufacturers as the White Brightness Lumens generated by the lamp. Projectors are measured by the number of lumens that are output by their lenses so that they can form a picture on the screen. The color brightness of a projector is obviously more important than how much light the lamp produces since that is what forms the picture on the screen.
All Digital projectors convert video images to digital colors by splitting them into their individual Red, Green, and Blue color images, then passing the corresponding beam of Red, Green, and Blue light through each of the RGB images, and recombining the individual RGB beams into one beam of light and displaying it on the screen. A projector’s Color Brightness is its brightness or lumens that strike the screen to form the image.
What is the difference between DLP Vs LCD projectors and which projector is better?
In LCD and DLP projectors, the difference lies in the way the image is displayed on the screen. To produce individual frames of a video, both 3LCD and DLP projectors split white light into RGB colors by using light bulbs and then pass them through LCD or DLP chips.
The following video will serve as an example of how all projectors work. This means that every second, the screen must be projected with 24 frames of separate individual images. It is necessary to split each of these 24 frame images into three frames, with each frame representing one of the basic RGB colors, and then recombine the three separate RGB image light beams into a single final beam of light.
3 LCD chips
There are three LCD chips in a 3LCD projector, one for every color R, G, and B. A B, R, or G frame is received simultaneously by each of the 3 LCD chips for 1/24 of a second. It takes 1/24th of a second for the color light to pass continuously through the frame. Prisms are then used to recombine the three colored image light beams from each RGB LCD chip and project them onto the screen.
A DLP projector generates RGB color beams intermittently through a DLP color wheel, and this DLP color wheel, as well as the DLP chip, need to be synced for the Red color beam to strike the DLP chip at the exact same moment as the RGB color beam strikes the color wheel. To reflect and project the red portion of the color frame on the screen, it is necessary to use the right mirror formation to do so. The same goes for the blue and green portions of the picture, which must be illuminated with the appropriate colored beam, and then reflected onto the screen by the appropriate mirrors so that the right colors are conveyed.
Frame rate
A 24×3=72 image of individual RGB colors is projected onto the screen per second for each frame of 24 frames per second. The 72 images per second consist of 24 red images, 24 green images, and 24 blue images. Due to the DLP color wheel blocking the Green and Blue light, the Red image is shown while only Red is being reflected. The light spectrum wastes 2/3 of its energy. Using DLP, a picture is projected on a screen using only 1/3 of the available light. Therefore, 3LCD projectors have three times as much color brightness as DLP projectors.
In order to accomplish this, some manufacturers of projectors, especially Epson, which manufactures 3LCD projectors, advertise that their projectors produce three times as much color brightness as their competitors.
DLP LED Hybrid Projectors: How Digital Light Processing Projectors Work
LED projectors with single chips and hybrids with LED and lasers are becoming more affordable and more common these days. When the room is dark enough, the brightness and picture quality is good enough.
In contrast to LED-only projectors, DLP hybrid projectors have no brightness issues. It was the inability to make the Green LED bright enough that was the Achilles heel of the pure LED projector. Pure LED projectors could not use the full power of Red and Blue LEDs since White light requires the intensity of all three RGB colors to be equal. It was the intensity of the green LED that posed the biggest challenge.
In the Hybrid projector, a laser is used to produce a bright green light which then fires up the Red and Blue LEDs at their full brightness, so that you can see the color of the projector at its best. As a result, you get a high-quality, bright Hybrid Projector with solid state lighting with all the advantages of being reliable, lasting a long time, using a long-life bulb, etc….for more information, please refer to our page about different types of light sources for projectors.