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Best Classroom Projector for Schools

What to consider while selecting a projector for classroom? Let’s discuss it.

An estimated figure indicates that more than 150 companies are involved in manufacturing of over 6000 various types of projectors worldwide till date of which 60 companies have stopped manufacturing. Some of the famous brands are IBM, HP, Compaq, Kodak, Phillips, Olympus, Lenovo, Xerox, Zenith etc. Apart from that, lesser known brands like Optoma, Benq, Epson, Taxan, Sanyo, Hitachi, NEC, Infocus, Mitsubishi along with Sony, Sharp, Panasonic are the largest manufacturers of projectors all around the world.

Key features are as follows:

  1. Brightness: the brightness of projector is measured in ‘ANSI lumens’. If the projector is used in dark spaces such as home theatre, between 700-1200 lumens is sufficient. However, in places where there is ambient light such as classrooms, one may opt between 2000 and 3000 lumens. The light from the projector can be damaging for the eyes. The brighter the projector, higher chances of having the same issue. So, it is recommended to install 2000 to 3000 lumens in classrooms for a 60 to 80 inch diagonal projected image.

  1. Resolution: It means the accuracy of the image that the projector reflects. The projectors fall into two categories- SVGA (800x 600 pixels) or XGA (1024x 768 pixels) apart from some SXGA (1280x 1024 pixels). These are the standard types of resolution but nowadays projectors are compatible to all resolutions which can be compressed or enlarged accordingly. The only thing is it might affect the image quality at times. For home theatre system users, recommends for 16:9 widescreen image and fall into one of the three resolution categories: WVGA (854x 480 pixels), WSVGA (1024x 576 pixels) or WXGA (1280x 720 pixels). The ‘W’ stands for Wide. One of the best ways to get the best output from a projector is by adjusting the laptop/computer resolution to the standard resolution.

  1. Contrast Ratio: The ratio between white and black parts in an image is the contrast ratio. The larger the contrast ratio, greater the difference between white and black the projector can show. For home cinemas, 2500: 1 is the ratio and for classrooms, 1000:1 to 2000:1 is enough.

  1. Data, Video & Audio Inputs: it is important to look out for different connections like VGA (RGB), S-Video, Composite Video, Component Video, DVI, HDMI, Audio inputs/ outputs, Memory card slots etc. For a classroom, a VGA connector is sufficient as most of the presentation is done through laptop or computer. The audio is not required if there is a provision to connect PC to an amplifier or speaker.

  1. Keystone Correction: it is the name given to the image when the projector sits below, above or centre of the screen. The keystone correction can be done by compressing the image at the bottom or top which results in a more professional image. Nowadays, almost all modern projectors have digital keystone correction

  1. Zoom/ short throw lens: This feature is available on many standard lenses or projectors. The zoom allows to enlarge or small images from the same distance. Short throw lenses are to create larger pictures from shorter distances. The short throw lenses are also used to reduce the shadow.

  1. Lamp Hours, Wattage & Cost: The present day 3LCD/ DLP projectors have 2000/ 3000 hours to 3000/ 4000 hours lamp life. 40- 60% is the extra lamp cost. Relatively cheaper projector lamps are Beng and Optoma. The standard wattage is in the range of 150- 300 watts. To reduce electricity bill lamps 200 wattages is recommended for classrooms as the usage is more.

  1. Screen or projection surface: One should project into a surface/screen to get the best out of the projector. A 16:9 screen is recommended for home screen users. In classrooms, it is advisable to use customized whiteboards (<1%glare) because the blackboards or other whiteboards will produce glare on the screen.

  1. Weight: normal LCD or DLP projectors weigh 1kg to 4kgs. For classroom anything from 1.5kg to 3.0 kg would be more than enough.

  1. Warranty: The warranty is separate for the projector and the lamp. Most manufacturers give 1yr warranty on projectors and 3 months/ 500hrs on the lamp. Some give up to 2-3yrs on projector and 1yr/ 1000hrs on lamp. The manufacturers with strong warranty offerings are Beng, Optoma, Epson, NEC.

  1. Price: Everyone would want their projectors to be cheap. For a regular classroom, SVGA model is sufficient as they can set PCs resolution to 800x 600 and there would be no loss of quality.

  1. Technology: LCD projectors are the first-generation projectors. But 3LCD, DLP, LCoS are manufactured currently. The LCoS or Liquid Crystal on Silicon is adapted by companies such as canon and few others. It is a combination of LCD &DLP technologies. Relatively these are quite expensive with exceptional picture quality. SXRD or Silicon X-tal Reflective Display is Sony’s variant of LCoS which is mostly used for HD or home theatre projectors. D-ILA or Digital Direct Drive Image is another variant of LCoS which is used by JVC. 3LCD and DLP are widely used by manufacturers in today’s market.

LCD or DLP : the recent technological progress has shown both LCD and DLP are on the same page quality wise and it is difficult to pick one over the another. LCD has shown great improvement in the last 2-3 years while DLP models are more priced than ever before. Both are in a good position to offer crisp, clear and vibrant images.

3LCD: The Liquid Crystal Display or LCD contains three separate glass panels, one for red, green and blue components. When the light passes through the LCD panels, individual pixels can be opened or closed to allow or block the light respectively.

DLP: The Digital Light Processing is the only all digital display solution which uses an optical semiconductor called Digital Micromirror Device or DMD chip to recreate source material.

Advantages and Disadvantages of DLP

Advantages:

  • less ‘chicken wire’ or (screen door) effect because pixels are very much closer together. This produces smoother images for video.

  • Higher contrast can be achieved

  • It has sealed optics which can be used in a dusty environment

  • DLPs are generally portable

  • Long lasting than LCD projectors

Disadvantages

Appearance of a rainbow effect when looking from one side of the screen or when looking away from the projected image to an off-screen object.

How DLP technology is superior to LCD projection?

DLP ensures that every pixel on the projected image gets the same amount of light. It contains one single chip instead of 3 bulky LCD panels. DLP also has reduced pixelation. LCDs are known for their screen door effect because it seems as the picture is being viewed through a screen door. On an overall level, DLP will always give you better visual image by retaining image quality.

School projectors are available on www.schoolsupermart.com

 


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