Universidad del Norte

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How does a projector work?

Rituraj Sengar (2018-12-18)

In its simple term, a projector is a device that is used to display an image on a large screen with the help of a series of chips, color wheels, lenses after connecting it to a video camera, PC, laptop, tablet. A video projector may be different on the basis of the technology by which the images are arrayed. The modern projectors are complicated both in implementation, design. The technology is used in accordance with the way the projector work. Nowadays, different types of technology are used in the video projector.

Below are the steps on how to a projector works. Have a look!

Among the different types of projectors are the LCD, DLP, LCos, D-ILA.

(There are different models of projectors available in the market like: )

In LCD or Liquid Crystal Display projectors, three liquid crystal panels, a lamp, a prism, and a filter are used to create the image. It's the lamp that gives light which beams through a polarizing filter. This filter accepts the light traveling on the same plane with the other light being blocked. From there, the light beams through a series of dichroic mirrors which let certain colors to be reflected in the light spectrum and separate the light into three primary colors-red, green and blue.

These colors are sent to another LCD panel which separates the light into the spectra and recombines the colors. Each color is sent through each panel which has the ability to control each color. The final LCD panel bends the light on the basis of the level of electrical current. The last dichroic combines the images of the three colors into the complete picture that is passed through the onboard lens and shown on the screen.

DLP, or Digital Light Processing depends on the DMD chip which is called the matrix of this projector. This matrix consists of millions of tiny mirror elements which are able to return to the right angle. The mosaic effect is used to expose one color on each mirror which is passed through to a rapidly spinning wheel that gets changed between the three. The light is beamed through the mirror on the screen and provides the white or black point. An electrical switch controls each mirror. The millions mirrors get united to make a high-resolution image.

How DLP projectors work:

The projector gets the digital signal from the TV receiver, computer, DVD player. An electronic circuit inside the projector encodes the signal. White light is created at the back of the projector by a powerful lamp. The lamp is passed through to rapidly rotating colored wheel, and produces any of the three colors at any particular instant. The grid of millions of colors is reflected by the light from three colors.

These mirrors produce a precise form of red, blue and green pixel and build up the TV picture. Finally, the light is accepted from the DMD chip by a lens and is pictured on the screen.

LCos, or Liquid Crystal on Silicon is the newest of the bunch which is most expensive and complex type of projector to build up. It falls on the type of hybrid between DLP DMD and 3-chip LCD technology. It is recommended that the color reproduction and clarity on this projector is superior to that of the previous technologies.

CRT projector contains three CRTs and each one is meant to produce one color of the RGB color model. It sends a beam of electrons at a phosphate-coated screen from the inside. This generates a single-color picture on the screen. Finally, the three images are reflected in the external screen through the lens and the mixing of these three images produces a full-color picture.

ISSN Electrónico1794-8886