DLP Vs LCD Vs LASER
Projectors have been around for more than a century and thanks to constant work done by scientists and engineers, projection technology is continually getting better. Projectors have now to come to prominence in residential applications as they offer a large image size and accurate colour reproduction while still being relatively affordable. Our quest to always make things bigger and better, has led us to embrace the primary technologies that have taken over the current projector market. These technologies being DLP, LCD and Laser.
To understand the differences and further infer the pros and cons between each kind of technology, we need to first briefly grasp the internal components and working of every projector. Every projector consists of the same components. The components being a light source, filter, combiner and a projection lens. These components form the basics of every projector. DLP, LCD and Laser technologies use the same components but with slight variations to achieve better picture quality and colour reproduction.
The DLP projector is the oldest of the three mentioned technologies and is the most widespread technology being used in residential applications today. DLP is the acronym for Digital Light Processing and is based on chipsets developed by Texas Instruments in 1987. These chipsets were then used to control a micro-mirror matrix within the projector. A DLP usually uses a lamp as its light source. A beam of light is then focused and made to pass through a rotating filter that splits the light passing through it into Red, Green and Blue. This RGB light then enters the housing of the Micro-Mirror matrix. Each mirror in this matrix can be made to pivot based on the final image that needs to be produced. This entails that the final resolution of the projector is completely dependent on the number or these tiny mirrors in the matrix. As the RGB light reflects off this micro-mirror matrix, it passes through a projection lens and is therefore projected onto the projection screen. This entire process happens so fast, that the human eye perceives it as one image/frame while there is actually 3 images projected at the same time, one in red, one in green and one in blue that sum up on the projection screen to create the final frame.
We all know that LCD stands for Liquid Crystal Display and is a form of technology that we find in our televisions. When it comes to an LCD projector, it is very similar to an LCD television. There are three primary differences between a DLP projector and an LCD projector. Firstly, there is no rotating filter in an LCD projector. An LCD projector uses 3 separate filters to separate the initial beam of light from the source and into Red, Green and Blue. Secondly, there is no micro-mirror matrix to reflect the light. Instead, LCD projectors use a filter on each beam of coloured light. This filter is made up of a liquid crystal panel in which each crystal can be manipulated to either let light through or not based on the final image needed to be achieved. The three individual light beams are then summed up by prisms and made to pass through the projection lens. This brings us to our third difference being that the final image projected on screen is the final image and not Red, Green and Blue versions. Some LCD projectors have now progressed to using LEDs as a light source.
Looking at how DLP and LCD projectors have completely different technologies, a Laser projector has only one primary difference. A Laser projector uses a laser as the initial source of light compared to a traditional lamp or LED. This laser can then be programmed to emit certain wavelengths of light that further enhances the dynamic range and perceivable colour gamut. The rest of the components of a laser projector are pretty much the same as an LCD projector.
An interesting technology that we would need to take a look at would also be LCoS. LCoS is the acronym for Liquid Crystal Technology on silicon. An LCoS projector is a hybrid projector technology between DLP and LCD. They use the same source and three beam technology as an LCD projector but use a micro-mirror matrix to reflect light through a liquid crystal filter to produce the final image. LCoS projectors are notorious for being large, heavy, hard to manufacture and expensive. This technology has been further built upon by companies like JVC and Sony to make their own proprietary versions of this kind of technology called D-ILA and SXRD respectively. D-ILA and SXRD focus on eliminating the spaces between each pixel thereby decreasing pixel shadowing light bleed between pixels and thereby increasing black levels. This also ensures a very high contrast ration for the image displayed. In addition to this. Sony has also started incorporating high refresh rates in their SXRD projectors.
In conclusion, there is no “best” projector technology. Each of them have their own pros and cons. While DLP is the oldest form of projector technology and can not achieve the clearest picture or best colour reproduction, the flow of movement is always seen to be better in DLP projectors. DLP projectors are also the most widespread and affordable. When looking at LCD and Laser projectors, we find that you get an inferior motion blur between frames while achieving much better picture quality. LCD and Laser projectors can also achieve high frame rates compared to DLP projectors as the number of moving parts ha s significantly reduced. The best colour reproduction however, would always be found in a Laser projector as the light source can be programmed to emit certain wavelengths of light which would help achieve a very accurate colour reproduction. Laser projectors would be the most efficient and energy conservative technology compared to DLP and LCD projectors since the original light source can be efficiently controlled and there is no wastage of light at the source. LCD projectors would be more efficient compared to DLP projectors since there would be no losses during the micro-mirror reflection process.
