The projector technology has grown by leaps and bounds in the recent years. The image quality output by the projectors has come a long way since the early days. Modern projectors output images that have excellent details and colors and allow the viewers to indulge in a cinematic experience.
The biggest change has been in the resolution of the projectors. An image output by display devices like TVs, monitors or projectors is made up of pixels. A pixel is the smallest unit of the image. An image can contain millions of pixels arranged horizontally and vertically. The number of pixels output by a device depends on its resolution. Devices that have a resolution of 1920x1080 (commonly known as 1080p) display 1,920 pixels horizontally and 1,080 pixels vertically. Simply speaking, the image is a grid of 1,080 rows each of which contains 1,920 pixels. The images output by 1080p devices contain a total of 2,073,600 pixels (1920 multiplied by 1080).
The higher is the resolution of a device, the better is the quality of the images output by it. The latest resolution available in devices is 4K. These devices produce well-detailed and crisp images that appear almost lifelike as they have more pixels than 1080p devices.
Until recently, the 4K resolution was only available in TVs and monitors. Nowadays, many companies have started manufacturing 4K projectors that produce images with high resolution and enhance the viewing experience of the users.
Buying a 4K projector can be quite confusing for the customers as companies employ different terminologies for marketing their projectors. Buyers will come across three main categories when shopping for 4K projectors – Native 4K, True 4K, and 1080p Pixel Shift 4K. While the three terminologies have similar names, the projectors belonging to them do not produce images of the same quality. It can be quite confusing to decide the right projector without understanding the difference between these three. It is important to understand how the projectors belonging to these three categories function to decipher the differences between them.
The 4K resolution was first seen in digital cinema projectors for displaying movies on the screen. These devices have a resolution of 4096 x 2160 which is also known as Cinema 4K. Projectors that output images with 4,096 pixels horizontally and 2,160 pixels vertically are known as Native 4K projectors.
These projectors display the input 4K image as is without processing it via techniques like pixel shifting. The image has a resolution of 8.8 megapixels, or 8,847,360 million pixels to be exact.
The devices either make use of DLP chips that have arrays of 4096 x 2160 mirrors (with each mirror representing a pixel of the image) or they employ LCD screens that have a similar number of pixels. Some projectors also use 4096 x 2160 LCoS chips which are hybrid chips that employ the features of both DLP and LCD chips. The projectors display the complete 4K image at an instant from the input device on the projector screen, unlike pixel shifting projectors that flash it multiple times.
Want to know more about the DLP, LCD, and LCoS technologies projectors use, read this article, DLP vs LCD vs LCoS Projector: The Advantages And Disadvantages
These devices are primarily employed for cinemas and other similar venues. A few companies like Sony manufacture native 4K projectors for home users also. The projectors output images that have excellent quality and are crispier than all other types of 4K projectors.
The Pixel Shifting 4K projectors are another type of projectors available in the market. These projectors can receive and display 4K videos and images. However, they make use of chips that have a resolution of 1920 x 1080 pixels. Projectors produce images using DLP or LCD chips. The DLP chips use mirrors to reflect the light onto the screen. The number of mirrors on DLP chips is equal to the resolution of the projector. A projector with 1920 x 1080 resolution has an array of 1920 x 1080 mirrors wherein each mirror represents a pixel. Similarly, Liquid Crystal Displays used in projectors also have pixels equal to the resolution of the projector.
To display a resolution of 4K, the manufacturer will have to fit 4096 x 2160 mirrors on the small array or use an LCD screen with more pixels. The process for producing the DLP or LCD chips for 4K resolution is complex and requires high precision. It increases the cost of the projectors and puts them out of the reach of most customers.
However, some companies make use of a technique known as pixel shifting for producing affordable projectors that can display 4K images. These projectors have 1920 x1080 chips making them effectively 1080p projectors. When these projectors receive a 4K input signal from a device, they process and split the original image having a resolution of 3840 x 2160 pixels into two images each with a resolution of 1920 x 1080 pixels. Each of the two resulting images has half the pixels of the original image. In other words, each resulting image contains half of the information in the original image, and the two images must be combined to produce the original image.
The projector displays both the images alternatively on the screen. However, one image is diagonally shifted by half a pixel in relation to the other. Each pixel of one image will be half a pixel lower and half a pixel to left or right as compared to the corresponding pixel of the other image.
As the projector alternates between the two images at such a high speed, the eyes of the viewers perceive the two images as one with a resolution that is closer to 4K. In reality, the total number of pixels on the screen is about 4.1 million which is twice the pixels of the 1080p image. If a user plays a 3D video on a 1080p pixel shift projector, the projector will automatically disable the pixel shift feature. Pixel shifting is also known as e-shift and 4K enhancement depending on the terminology used by different brands.
True 4K projectors designed for consumers do not exactly have a native 4K resolution. The height of the images produced by true 4K projectors is the same as the height of the images output by the native 4K projectors, but they have lesser width. These projectors display 3,840 pixels horizontally and 2,160 pixels vertically which amounts to 8,294,400 pixels onscreen. It is a smaller resolution as compared to the resolution of native 4K projectors. The images produced by these projectors are said to have a resolution of 8.3 megapixels. True 4K projectors output images that have 552,960 fewer pixels than the images output by the native 4K projectors. These projectors are also known as 4K UHD projectors. Their resolution is the same as that of 4K LCD and LED TVs and monitors.
True 4K projectors can be broadly classified into two categories depending on the way they produce images.
Two-Phase Pixel Shifting True 4K Projectors
The two-phase pixel shifting true 4K projectors make use of the pixel shift technology like the 1080p projectors. However, instead of using a chip that has a resolution of 1920 x 1080, these projectors use a chip with 2716 x 1528 pixels. The DLP 0.66" 4K UHD DMD chip from Texas Instruments is popularly employed in projectors of different companies.
JMGO U1 True 4K Projector with Two-phase Pixel Shifting
(Not available outside of China currently)
The chip has a micromirror array consisting of 2716 x 1528 mirrors. Each mirror represents one pixel on the screen. The projector splits the original image into two images. Each resulting image has 4.15 million pixels. The projector displays the two resulting images alternatively, each of which contains half the information of the original image. The projector alternates between the two images at an exceptionally fast rate and the eyes of the users perceive the onscreen image to have 8.3 million pixels which is quite close to the resolution of the native 4K projectors.
Four-Phase Pixel Shifting Projectors
The four-phase pixel shifting true 4K projectors also use the pixel shifting technology. However, they make use of a chip that has a resolution of 1920 x 1080p. The DLP 0.47 4K UHD DMD chip from Texas Instruments is used in quite a few models of projectors available from different brands.
The projector splits the input 4K image into four images. It then cycles between these four images to display them on the screen. Each image consists of over 2 million pixels, and the four images have approximately 8.3 million pixels in total. As the projector cycles between the images at a rapid rate, the eyes of the viewers perceive these images as one which has over 8.3 million pixels. In reality, the processor is only displaying one-fourth of the pixels at a time. Choosing the right projector
The difference in the quality of videos output by a pixel shifting 1080p projector and a 4K projector is hard to notice. However, when these projectors are used for complex graphics or textual presentations, the difference in quality is quite visible. Therefore, 1080p pixel shifting projectors are best recommended for homeowners who want to buy the most affordable projectors primarily for viewing movies. Individuals who mostly watch 1080p movies on their projectors and occasionally indulge in a 4K movie can consider a True 4K projector.
The quality of the images output by the two-phase pixel shifting true 4K projectors is better as compared to the images produced by the four-phase pixel shifting true 4K projectors. However, the four-phase pixel shifting projectors are more affordable. True 4K projectors are available from most brands, and there is a large variety of options available to the users.
Native 4K projectors are the most expensive of the lot, but they also produce the best quality images. Users who want the best movie experience and have the money to spare can consider native 4K projectors. Designers who have to present extremely high-resolution images in their presentation to clients or peers will benefit from the high clarity of native 4K projectors.
While the resolution of a projector is a primary factor to consider while buying one, it is equally important to take into consideration other parameters. These include the brightness rating expressed in lumens, the contrast ratio and the cost of the projector. Ultimately, the best projector for a buyer will depend on his or her requirements and budget.