Projectors can be divided into three distinct categories depending on their image projecting mechanism – DLP, LCD and LCoS projectors. They have different specifications and come with their own advantages and disadvantages. It can be quite confusing for the buyer to choose a suitable projector out of these three. It is best to go through each of these technologies and how they function in order to determine the right projector for your specific requirements.
DLP projectors were the first to be introduced among all three projector models. DLP or Digital Light Processing projectors use a Digital Micromirror Device for projecting images. DMD is a chip that has an array of micromirrors arranged in rows and columns. The number of mirrors on the chip will depend on the native resolution of the projector. If the projector has a resolution of 1080p (1920×1080 pixels), then the DMD chip will have 1080 rows with 1920 micromirrors in each row which is 2,073,600 mirrors in total. Each mirror represents one onscreen pixel. The light from the light source such as a lamp or LED is directed at the DMD device.
Each mirror can be turned to “on” or “off” position. If it is in “on” position, it reflects the light from the source and projects a light pixel on the screen. If it is in “off” position, it projects a dark pixel on the screen. The projector switches the position of mirrors several times in a second depending on the input signal. The mirrors collectively project the image, but it is in grayscale.
A color wheel is used to add color to the image. The wheel is transparent and rotates to alter the frequency of white light from the source to change it into red, green or blue color. The projector can alternately reflect lights of different colors to create secondary colors. If a magenta pixel has to be displayed on the screen, the projector will control the DMD chip and color wheel to alternate between red and blue colors at a fast rate. It projects the whole imagery using these techniques and can create up to 16.7 million colors.
Some DLP projectors use three DMD chips with a distinct light source and color wheel for each one of them. They can project images with a superior resolution and highly accurate colors.
Advantages of DLP Projectors:
Highest Brightness Levels – One of the primary reasons for buying DLP projectors is their brightness levels. DLP projectors typically have the highest brightness rating in comparison to LCD and LCoS projectors when considering projectors with similar light sources. They are the ideal choice for environments with high amounts of ambient lighting.
Good Contrast Ratio – DLP projectors have very good contrast ratio in comparison to LCD projectors making them a great option for home theatres. The contrast ratio of a projector specifies the variation between the darkest and whitest pixel it can project on the screen. Images projected by projectors with high contrast ratio appear more realistic. The text is sharp and crisp rendering the DLP projectors suitable for offices also.
Cheapest Option – DLP projectors are the cheapest of all three types of projectors and a feasible option for most home and offices. There are decent DLP projectors available for under $1,000 (USD) that will suit homes and offices. It makes them ideal for users who want to buy a decent projector without spending a great deal of money. Some DLP projectors use three color wheels instead of one and will be more expensive than the DLP projectors having a single color wheel.
Disadvantages of DLP projectors:
Rainbow Artifacts – One of the biggest reasons that people avoid DLP projectors is the rainbow artifacts in the images projected by them. The brightest pixels on the screen may have a rainbow-like reflection. It is produced when the color wheel rotates at a slow speed. It can be quite annoying to some viewers who are sensitive to it though others may not find it distracting at all. LCD and LCoS projectors don’t suffer from rainbow artifacts.
Some projectors use LCD technology for projecting images. They contain Liquid Crystal Panels instead of DMD chips. Just as an LCD TV’s screen is composed of pixels, the panels of an LCD chip contain pixels arranged in rows and columns. The number of pixels is equal to the native resolution of the projector. Each pixel on the LCD panel can be controlled individually by passing an electric current. The chip allows the light from the source to pass through a pixel for creating a light pixel and blocks it to create a dark pixel on the screen.
LCD projectors typically use three distinct LCD panels for projecting images. All panels project the same image at the same time. The light from the lamp or LED is divided into red, blue and green wavelengths by dichroic mirrors. Each beam hits a separate LCD panel producing three different colored variations of the image. The light from the three LCD panels is then combined using a prism to produce the final image.
Advantages of LCD Projectors:
High Power Efficiency – LCD projectors have high power efficiency when compared to DLP and LCoS projectors with similar specifications. They consume far less power than DLP projectors and are slightly more efficient than LCoS projectors.
Excellent Color Reproduction – LCD projectors have the best color reproduction making them the ideal choice for watching movies and videos. It is because, unlike DLP projectors, they don’t use a color wheel which reduces color saturation making the colors in the imagery dull.
No Mechanical Components – Unlike the DMD chips of DLP projectors that are electro-mechanical in nature, the panels of LCD projectors don’t have any moving parts. The fewer moving parts ensure that the projectors don’t suffer mechanical failure.
Disdvantages of LCD Projectors:
Worst Contrast Ratio – LCD Projectors have the lowest contrast ratio out of the three projectors. The images projected by them are not as sharp as those of DLP and LCoS projectors. LCD projectors are more suitable for movies and video playback. They are not able to display text as clearly as DLP or LCoS projectors and hence are not recommended for offices.
Dust Prone – Stay away from LCD projectors if you are going to use them in dust-prone environments. The light paths of LCD projectors are not sealed, and their LCD panels can suffer from dust blobs over time. The blobs can cause artifacts in the projected images and negatively impact the viewing experience of the user.
Lowest Brightness Rating – LCD projectors will generally have the lowest brightness rating when compared to DLP and LCoS projectors with similar features. They are not suitable for areas having medium or high amounts of ambient lighting and are better for dark rooms and low-light environments.
Pixel Burnout – LCD Projectors are not designed for continuous use as their LCD panels can suffer from pixel burnout with extensive usage. A dead pixel doesn’t allow light to pass through and impacts the viewing experience of the user.
LCoS projectors are relatively new offerings as compared to DLP and LCD projectors. They feature Liquid Crystal on Silicon (LCoS) panels that share the properties of both DLP and LCD panels. The panels have pixels in its liquid crystal layer that can be controlled using electric current and a semiconductor silicon layer that enables them to reflect light like mirrors in DLP chips. The hybrid technology enables them to project images that are superior to both DLP and LCD projectors.
There are three LCoS panels used on the projectors. Light from the source is split into red, blue and green beams, each of which is then guided onto a separate LCoS panel. The light passes through the three LCoS panels to produce red, blue and green variants of the same image. The distinct images are then combined using a prism for producing the final image to be projected on the screen.
Advantages of LCoS Projectors:
Best Contrast Ratio – LCoS projectors have the best contrast ratio out of the three projectors thanks to their hybrid technology. They can project both movies and textual documents with excellent sharpness and detail level. It makes them the ideal option for high-end home theatres as well as offices that need projectors for presenting designs and images with high detail levels.
Best Picture Quality – As LCoS projectors use hybrid technology, they can output images that are better and sharper than the images projected by both DLP and LCD projectors. Users who want the best cinematic experience may find LCoS projectors to their liking.
Disadvantages of LCoS Projectors:
Average Brightness Rating – Traditionally, LCoS projectors have not fared very well when it comes to brightness ratings. But refinements in LCoS technology have ensured that the brightness of LCoS projectors is acceptable for most use cases. A few modern LCoS projectors have brightness levels similar to their DLP counterparts and can be used in environments with low to moderate ambient lighting.
Expensive – LCoS projectors are the most expensive of the lot when considering other types of projectors with similar specifications. Only those users will purchase LCoS projectors who want the best quality and have the money to spare.
Heavy – LCoS projectors are the heaviest among the three types of projectors. They are difficult to carry as compared to DLP and LCD projectors. It makes them unsuitable for users who want to move their projector from one room to another.
DLP vs LCD vs LCoS Projectors – Which Should You Choose?
In the end, the ideal projector for you will be determined by your needs and the amount of money you are willing to spend on it. A high-end DLP projector will be better at videos than a low-end LCD projector and vice versa. It is best to request a demonstration of different projectors for determining the right one for your needs.
In general, if you need a projector strictly for watching movies, then an LCD projector will suit your needs. DLP projectors are ideal for multipurpose use and are the most affordable out of the three types of projectors. LCoS projectors will find favors with users who want the best picture quality.