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Projectors have become an essential part of our homes, offices, and commercial establishments today. They produce realistic images that allow the users to immerse themselves in the world of their favorite movies and shows. Projector technologies have grown by leaps and bounds over the last several decades. The progress of the projectors is a result of continuous research and innovation. The story of the evolution of the projectors is as colorful and vibrant as the images they produce.
Modern video projectors could not have existed before the introduction of computers. However, several devices were invented before computers by ingenious minds of their times. These devices laid the foundation for the development of the modern projectors.
One of the earliest devices that resembled a projector was the magic lantern. It was created in 1659 by Christian Huygens, a Dutch scientist who used a concave mirror to direct light from a lamp onto a glass slide that had the image. The light passed through the glass slide and projected the image on a screen using
focusing lenses. Magic lanterns were one of the first image projecting devices to gain popularity in the education and entertainment domains.
Jan van Musschenbroek's magic lantern is projecting a monster
Around 1756, Swiss physicist and engineer Leonhard Euler developed the opaque projector (also known as the episcope). An image or an object was placed inside the projector. The light from a bright lamp located above the object projected the image of the object onto the viewing screen via a system of mirrors and prisms.
Jacques Charles, a French scientist, invented a device called the megascope. It functioned like the opaque projector and was primarily used by Jacques Charles for lectures. Henry Morton demonstrated another variant of the opaque projector in 1872. It was designed for large audiences and made use of an oxyhydrogen lamp to project the images.
The 1940s to 1960s
The decades from the 1940s to 1960s saw the development of the earliest computers. The decades also witnessed the widespread adoption of different types of optical projectors. These projectors made use of optical mechanisms and bulbs for projecting images.
One of the earliest projectors to become popular during this era were the slide projectors. These projectors were used to project transparent photographic slides on the screen. Light from a source such as an incandescent light bulb or limelight was directed onto the 35mm slides through a condensing lens by using reflectors. The light passed through the slide onto a focusing lens that projected a large image on the screen. The slides contained family pictures or educational material. Slide projectors became common in educational institutions as well as homes during this decade.
The overhead projectors or OHPs are a variant of the slide projectors. They were introduced a few years after the slide projectors. The working of an overhead projector is similar to the slide projector. The light from a source like a high-powered halogen bulb is passed through a condensing lens onto the object for projecting images on the screen.
However, these projectors make use of transparencies instead of slides. Transparencies are transparent sheets with a size similar to the paper sheets. The image could be drawn or printed on these transparent sheets. They have to be placed face-up on the projector.
Overhead projectors have a mirror that reverses the mirror image produced by the face-up orientation of the transparencies. Overhead projectors also have an inbuilt blower that prevents the bulb from overheating. These projectors were popularly used in the US military training programs during the World War II as well as in educational institutions and offices. Slide and overhead projectors remained popular almost up to the late 2000s when the digital projectors superseded them.
The Beginning of the Digital Era – the 1970s to 1990s
The years from the 1970s to 1990s witnessed the introduction of some of the earlier digital formats. Hardware and software innovations gained momentum and there were some groundbreaking discoveries. Modern projectors still utilize refined versions of the technologies discovered in this era.
The document cameras are commonly used projecting devices that were introduced in the 1970s and 1980s. They are also known as visual presenters. These devices have a high-resolution camera that captures the images of the documents or objects in real time and displays them on a screen. They can be connected to a monitor or an interactive whiteboard. Some models of the document cameras can also be connected to video projectors. They allow the users to rotate the camera around the objects as desired. Document cameras have a zoom feature that enables the users to enlarge small print or highly-detailed images.
The document cameras superseded overhead projectors and became popular in lecture halls, offices, courtrooms and even in the medical domain. They produce more realistic and vibrant images as compared to the overhead projectors.
Epson DC-21 High Definition Document Camera
The introduction of the Digital Light Processing (DLP) technology was a significant leap in the projector landscape. Overhead and slide projectors were adequate for still images, slides, and transparencies; however, they were not as good for presenting videos.
Dr. Larry Hornbeck invented the first DLP chip called the Digital Micromirror Device (DMD) in 1987. The device consists of an array of small mirrors wherein each mirror is responsible for projecting one pixel on the screen. The mirrors reflect light from a source like a Xenon lamp onto the projector screen to produce the images. The alignment of the mirrors is controlled digitally depending on the image that has to be output.
The first DLP projector became commercially available in 1996. It produced images with higher accuracy and at a faster speed as compared to the different projectors available at its introduction. Initially, DLP projectors utilized a single DLP chip, but three DLP chips variants were also launched later. After their introduction, the DLP projectors were adopted quickly in different sectors including the entertainment, education and commercial ones. DLP projectors are still popular in home theaters, educational institutions, and offices due to their decent image quality and affordability.
Modern day DLP Projector
The introduction of the LCD technology enabled the creation of the LCD projectors. While liquid crystals were discovered several decades ago, displays made from them became available commercially only in the 1960s and 1970s. An early prototype of an LCD projector was presented at the SID Conference in 1972. It was a modified slide projector with a matrix-addressed LCD and was created by Peter J. Wild. However, early models of LCD projectors had low resolution and their LCDs were prone to damages from the heat produced by the light source.
Gene Dolgoff was another inventor who had been working on creating an LCD projector since the late 1960s. He was only able to complete a prototype LCD projector in 1984 when the LCD technology became more refined. He improved upon his design, patented it in 1987 and started his company Projectavision, Inc. in 1988. He also licensed the technology to other companies. The first commercial LCD projector called “Imagina 90” became available in 1990.
Today, Epson and Sony are the two major companies that manufacture LCDs for projectors. LCD projectors are popularly used in different avenues.
Epson LCD Projector
The Liquid Crystal on Silicon (LCoS) is one of the latest technologies being used in projectors. The LCoS technology was introduced in the 1970s for creating displays. It was primarily utilized for creating rear-projection display products over the next few years. However, LCoS displays were made obsolete by the LCD and plasma display panels. The technology is now primarily being used for projectors.
LCoS chips make use of a liquid crystal layer on a silicon backplate that reflects the light from the source. It is a hybrid technology that has the properties of both the LCD and DLP chips. It enables the LCoS projectors to produce high-resolution images. Sony introduced one of the first LCoS projectors in the market in 2005 that made use of three LCoS chips. Today, LCoS projectors are manufactured primarily by Sony, JVC, and Canon.
The 2000s and Beyond
In the last couple of decades, manufacturers have refined the projector technologies for yielding realistic image quality. Modern projectors use enhanced versions of the DLP, LCD and LCoS technologies. Properties of the projectors like the resolution, brightness and contrast ratio have improved significantly in the last few years allowing them to produce lifelike images.
4K and UHD projectors
Continuous improvements in technologies have allowed manufacturers to produce high-resolution displays ranging from 1920x1080 pixels to 3840x2160 pixels. There are new variants of the projector chips available that utilize special technologies to output images of UHD (3840x2160) and 4K (4096x2160) resolutions. The images produced by these projectors have extensive details and allow a cinematic and engaging experience. UHD and 4K projectors became available for commercial applications (digital cinema) in the early 2000s and have also gained the attention of the consumers in the recent years. Sony introduced its first 4K projector for cinemas in 2004 with products from other manufacturers releasing soon after. In the last few years, companies have started manufacturing projector models with 4K and UHD resolution for home and office users also.
Sony 4K Projector
The evolution of the projector technologies has made the creation of portable and lightweight projectors a reality. Texas Instruments released the DLP PICO technology in 2012. The new DLP chip is even smaller size than the standard chip and can be embedded into devices such as smartphones and tablets. The technology allows the creation of smart projectors that have a small form-factor and are portable. Pico LCD and LCoS technologies have also been introduced and are being used in different small form-factor projecting devices.
Laser projectors are the latest innovation in the field of projectors. Laser projectors, in essence, use one of the three technologies for producing images – DLP, LCD or LCoS. However, they employ lasers as the source of light instead of lamps or LEDs. As lasers produce a highly coherent beam of light, it allows the projector to produce high-quality images. They also generate less heat and have a longer lifespan.
Laser projectors were initially developed for commercial applications. 4K laser projectors became available in cinemas in 2013. Since then, a few companies like Sony and Epson have also started manufacturing laser projectors for home users.
Laser TVs have also become available in the recent years. Laser TVs are essentially projectors that have a short-throw ratio enabling them to produce large images at a distance of a few inches from the screen. Laser TVs produce images that are at par with LCD and plasma TVs which has led to a surge in their popularity.
Laser Ultra Short Throw Projector
With the modern technology emphasizing on creating smart devices with small form-factors, there has been a demand for the smart projectors. These projectors have a dedicated processor, RAM, and storage besides the projecting mechanism. They come pre-installed with an operating system like the Android OS and can display the images from their storage. Smart projectors can even connect to the Internet using a SIM or via a Wi-Fi network. They are lightweight and super portable allowing users to carry them along.
The evolution of the projectors has been a continuous process that has been carried out over several decades. Modern projectors have improved by leaps and bounds, especially in the last few years. Innovations have not only improved the quality of images output by the projectors but also made them more affordable. Projectors are only going to become better and increasingly popular from hereon.