Digital projection options, explained by Christie
by Curtis Lingard, Christie Digital Systems
With the range of projectors available, how do you make the right choice for your needs? How big and bright an image do you need? Do you choose 3LCD, 1DLP®, 3DLP®, lamp, laser phosphor or RGB laser? Where should the projector be installed and will it be easy to use? What maintenance is needed, and how much will all this cost?
Identify your priorities
Every installation is unique. There is no one-projector-technology-fits-all approach. Choosing the right technology comes down to environment, desired image quality, ease of use, maintenance, and cost. Defining room size, allowances for depth of display, viewing distance, and how much ambient light there is will determine your specifications for brightness and projection screen selection. Assessing lens throw distance, resulting projector placement and ongoing maintenance access will also narrow the choices. Will people be up close to the projected image or positioned farther away? An audience’s proximity to and interaction with the content, along with potential obstructions to the light path, has an impact on projector setup and choice of projector.
Assess your content
After reviewing the environment you will be outfitting, your next consideration is content. Will your content be mostly black and white spreadsheets, or brightly-colored content for maximum visual impact and perhaps 4K resolution? Beyond what the content does and how it needs to be displayed, consider how you need to interact with the content. Also, consider where your content will be placed and what resolution is required to have the image scaled and displayed correctly.
Once you know your content and how it fits into the environment, you can zero in on a particular projection category – 3LCD, 1DLP or 3DLP, laser phosphor or RGB laser. Depending on your content, color reproduction variables will also factor into the decision. If you are working with big images, bright colors and the need for high-impact visuals, you may lean toward 1DLP or 3DLP.
If the room is small, such as in a museum, you may find 3LCD projectors are a good, budget-friendly fit. This is also when you start to compare projector options and features within a manufacturer’s projection lineup. If 1DLP meets your budget and performance goals, you can narrow your choice based on projector and lens combinations, light source specifications, contrast ratio, orientation, size, shape and weight.
Comparing noise levels among projectors is also important; noise levels may be less important for a theme park ride or live event, but it is a big factor in a meeting room or smaller venue.
For multi-projector setups in theme parks, built-in warping and blending capabilities of DLP lamp-based and laser projectors allow you to adjust the content precisely so it appears as intended.
You can also compare how easy it will be to replace consumables and perform maintenance tasks on your projector without removing it from its installation. For instance, will you need to take your projector down to replace a filter, or can you access the filter while your projector is mounted? If it is in a difficult to reach spot, consider solid-state illumination so replacing lamps or filters doesn’t come into play.
Finally, there is total cost of ownership (TCO); which is purchase price + maintenance costs + operating costs. Know how your budget works. Larger venues may be able to invest more up front – such as in 3DLP or true laser – and achieve a lower TCO since maintenance and operating costs are much lower over the long-term. • • •
As Product Manager, Christie Digital Systems, Curtis Lingard is responsible for the lifecycle of 1DLP and 3DLP projectors that meet the needs of global clients in various applications including fixed installation, rental staging, artistic and architectural displays, simulation and visualization. He is also responsible for developing marketing collateral that highlights product requirements and specifications. Lingard has spent more than two decades in the AV industry, beginning with stage and theatrical lighting before joining Christie in 1998.
Comparing projection technologies
3LCD projectors are one of the least expensive projectors available. Most use inorganic liquid-crystal display panels that transmit, rather than reflect, light. Three panels are commonly used, one for each (red, green, blue) color. Optical filters split the white light from the lamp into the three colors and direct the colors through their respective panels. An image forms on a panel by varying an electrical signal sent to each pixel in quick succession, creating incredible color accuracy and contrast. With typical brightness levels up to 12,000 lumens, they are ideal for higher education, corporate and worship facilities.
DLP (1-chip, 3-chip)
A step up from 3LCD is the 1-chip (1DLP) and 3-chip DLP (3DLP)projectors. The heart of every digital light processing (DLP) chipset is an array of highly reflective aluminum micromirrors known as the digital micromirror device (DMD). The 1DLP approach places a rapidly spinning disk (color wheel) between the DMD chip and a light source.
The 3DLP method uses a DMD for each primary color (red, green, blue) which are optically converged, producing a single image. DLP technology provides excellent color control and consistency. Because the light is reflected out of the projector, DLP projectors tend to offer really high brightness in a smaller unit, while using less power. Using a proven robust reflective technology like DLP also makes DLP more suitable for high usage applications. Brightness for 1-and-3-chip DLP projectors ranges up to 60,000 lumens and resolution from SVGA to 2K and 4K. They are used in meeting rooms, auditoriums, small venues and attractions (1DLP) to large venues, live events, projection mapping spectaculars and theme parks.
Illumination sources for all projectors range from mercury and Xenon lamps to solid-state illumination like LED, laser phosphor and RBG laser.
Lampless (also called solid-state illumination)
In recent years, solid-state illuminated projection technologies have become available. Laser phosphor and RGB laser are two main illumination platforms. Typical laser phosphor projectors use a blue laser diode and a spinning phosphor wheel as the light source instead of a lamp. This means no lamps and often no filters need replacing, which reduces downtime and maintenance costs, while providing high brightness. Laser phosphor projectors are popular in high-use settings like boardrooms, classrooms and location-based entertainment.
RGB laser technology, often referred to as ‘pure laser,’ uses individual red, green and blue lasers to generate light. Producing the brightest images and the purest colors, RGB laser technology is the pinnacle of solid-state illuminated projection, generating light up to 60,000 lumens today. RGB laser is ideal for giant screens, rental staging, projection mapping, location-based entertainment and applications where high-brightness and reliability are important.