Projector technologies make image projection possible. They are responsible for the conversion of audio and visual input.
The result is the projected output that gets displayed on projector screens.
The DLP technology makes projection happen. It is one of the three main technologies used in image projection today.
Do you own a DLP projector? You should stick around and learn more about it.
This article explains how DLP technology works. It also highlights the advantages of DLP technology.
- Digital Light Processing Technology
- History of DLP Technology
- How Does DLP Technology Work?
Digital Light Processing Technology
DLP (Digital Light Processing) technology employs one or more chips. The chips contain tiny mirrors in their thousands.
This technology uses the digital microscopic mirrors and a spinning color wheel. They help it generate and project images.
DLP projectors produce sharp images without using external filters. They are adopted in a majority of digital projections for cinemas.
They have great response time as well as 3D capabilities. They also have little or no input lag, so they make good gaming projectors.
DLP technology is used for more than just image projection. It is also adopted as a source of light by some printers.
Digital Light Processing is used in 3D printing. It helps to change resins to 3D objects.
History of DLP Technology
The DLP technology was developed in 1987. American physicist, Larry Hornbeck, developed it under Texas Instruments.
Texas Instruments invented the DLP imaging device. Afterwards, the first DLP-based projector was made by Digital Projection Ltd.
It was 1997 and it was a 3-chip DLP projector. Since then, the DLP technology has been widely used in projectors.
How Does DLP Technology Work?
The image displayed by DLP projectors is created with a Digital Micromirror Device (DMD). The DMD consists of tiny microscopic mirrors.
The mirrors are arranged in a rectangular pattern on a DMD chip. The distance between the mirrors on the DMD is about 5.4 µm or even less.
This is due to the tiny nature of the mirror used. The mirrors represent the pixels used to project the image on screen.
An image’s resolution determines the number of mirrors to be used. The quality is best if the resolution is equal to the pixels available.
Common DMD sizes include: the 800×600, 1024×768, 1280×720, and 1920×1080 (HDTV) pixel numbers.
The microscopic mirrors can switch positions quickly. They are either in an ‘on’ or an ‘off’ position.
In the on position, they reflect light through the projector lens. In the off position, they deflect it.
Deflected light is absorbed by the heat sink. The heat sink is also termed the light dump.
Grayscales are produced by rapidly switching the mirrors between the two positions. The on-time to off-time ratio plays a role.
Color Production in DLP Projectors
Color generation in DLP projectors is readily carried out using two main methods:
- Single-chip method (1DLP)
- Three-chip method (3DLP)
A third process (still being developed) operates by a sequential illumination. It uses three diodes that emit colored light.
Single-chip Projectors (1DLP)
Projectors with single DLP chips generate color in two ways.
- A color wheel can be placed between the DLP chip and a white light source.
- Individual sources of light such as LEDs can be used in order to produce primary colors.
The color wheel is divided into color sections:
red, green, and blue. Sometimes, white or a clear color is included.
In some cases, subtractive colors like magenta, yellow or cyan are substituted for white.
A new system of color performance, BrilliantColor, creates broader color spectrums. It uses subtractive colors in place of white.
Why? Processing both primary color types results in a wider range of color combinations.
Light from the lamp passes through the color wheel. The rotating color wheel is synchronized with the DLP chip.
When the red section of the color wheel is facing the lamp, the red component is displayed on the DMD chip. The same happens for blue, green and the other color sections.
This process depends on speed. The different colors are displayed in sequence at a very fast rate.
The speed makes the sequential flashing indistinguishable. A viewer sees a fully colored image rather than separate flashes of color.
Earlier models operated at one rotation per frame. Today, the majority of systems can go up to 10× that rate.
The Rainbow Effect of The Color Wheel
Sometimes, color generation doesn’t occur at a fast enough rate. This results in something called the rainbow effect.
It is common in single-chip DLP projectors.
Viewers see short flashes of red, green and blue shadows rather than the full-colored image.
It is observed when one quickly glances over the lighter areas of the image on screen. Also, it is noticed on scenes with fast movements.
Only projectors that use the spinning color wheel may experience this phenomenon.
Three-chip Projectors (3DLP)
Three chip projectors generate colors by using prisms. The prisms split light gotten from the projector lamp.
The projectors have a chip for each primary color. When the light is split, each primary light color is directed to its DMD chip.
Next, the colors are recombined at appropriate ratios to form the required hue. The color formed is then passed out through the projector lens.
The 3DLP technology is of great quality. It is used in high-end home theatre projectors, and cinema projectors.
Movie theatres use 3-chip projectors with high color precision. They are able to produce about 35 trillion different colors.
This is far more than the human eye can detect.
Three-chip DLP projectors do not make use of the spinning color wheel. Hence, they do not manifest the rainbow phenomenon.
1. How long do DLP projectors last?
The lifespan of a projector is determined by its lamp. This is because light is an important factor in color production.
Hence, lamp deterioration affects the projector’s output performance.
The life expectancy of a DLP projector’s lamp is between 2000-5000 hours. After 2000 hours, the lamp’s efficiency may reduce to about 70%.
2. Is DLP a laser?
No, the DLP and laser technology are not the same.
DLP projectors use lamps and DMD chips to generate images. Laser technology replaces traditional lamps with laser light sources.
Laser projectors make use of light emitted as a result of radiation.
Laser technology may use a DMD chip or other projection chips. However, their light sources are different.
3. What is better: DLP or LCD projectors?
Choosing a projector is dependent on several factors. Ask yourself some questions.
Where do you want to use it? How mobile does it have to be? What is your budget?
Qualities such as brightness, clarity, and color quality should also be considered.
Both projector types have their pros and cons. Deciding which is better depends on your needs.
LCD projectors produce brighter images with great picture quality. However, DLP projectors are portable, and generally more reliable.
The DLP projectors are often called lamp-to-chip projectors.
The DLP technology has been around for a while. It has undergone improvements over the years.
The single-chip DLP projectors have limitations such as the rainbow effect. This limitation is absent in three-chip DLP projectors.
DLP projectors are reliable, portable and have high contrasts. These make them great options for viewers.