LCD Projectors and Document Cameras Defined

Or everything you wanted to know but didn’t know who to ask . . .

Projectors- Two main types:

• Digital Light Processing (DLP)

– Reflect light again hundreds of tiny mirrors called digital micro devices (DMD)

– Each mirror represents one pixel

• Liquid Crystal Display (LCD)

– Operates by shining light through transparent red, green and blue LCD cells

– Typically brighter than DLP projectors with the same lumens

Does Size Really Matter?

• Ultralights - used for traveling presentation

– Weigh under 3 lbs.

– Typically 1000 - 2500 lumens

• Room Projectors

– Weigh in at 8 - 25 lbs

– Brighter than ultralights, 2500 - 5000 lumens

• Fixed Projectors

– Most expensive

– Usually in Auditoriums

– Range from 1000 - 10,000 lumens

Resolving the Resolution Issue

• Each projector has its own “native” resolution at which it works best

• For best projection - set the computer and the projector at the same display setting

• the most popular today being the XGA 1024 x 768 sold in the 4:3 aspect ratio

Projector Resolution OptionsResolution Description

SVGA800 x 600

Great for those on a tight budget. They’re good for PowerPoint presentations that include clip art or line drawing, black and white, showing documents, etc. They are not good for presentations that require a lot of detail or video.

XGA*1,024 x 768

Most computers still output in native XGA, so matching an XGA projector to your computer ensures you won't lose any detail. These are good general purpose projectors.

SXGA1,280 x 1,024

SXGA projectors are high resolution, and will be more expensive than XGA. These are targeted for high end personal computer users.

SXGA+1,400 x 1,050

SXGA+ projectors are becoming more popular, and there are several offerings available in both budget and high-end configurations. These are very good for detailed photography and graphics.

UXGA1,600 x 1,200

UXGA is for very high end high resolution workstation applications that require exacting detail. These are expensive projectors that support a broad range of computer equipment.

* The most popular projector resolution

Is what you see what you get?

• 4 Factors Determine Image Quality– Contrast– Color– Brightness– Illumination spread

Contrast and Color

• Difference between white & black

• Most important when projecting video

• Contrast ratio 250:1 minumum - 2000:1 great!

• More colors the better - especially for video

• Should be able to display 16 million colors or more

Brightness and Illumination

• Brightness indicated by ANSI Lumens

• Minimum 2500 Lumens for a classroom

• Illumination spread - is the image the same brightness from top to bottom and side to side

• 85% illumination uniformity or better

Let the Light Shine!

• Projector Lamps come in 3 main types:

– UHP - Ultra High Performance

– UHE - Ultra High Efficiency - most common

– Metal Halide

• Lamp life - 1000 - 4000 hours

• Lamp Cost - $300 - $600

– Include an extra lamp in the cost of the projector

Conveniences (Extras)

• Wireless Projector• Networked connections - remotely

controlled• Component video inputs for higher

quality video• Digital Keystone correction• Wireless mouse control• Dual computer input

Document Cameras

• Resolution– Two categories - low resolution output (composite

and/or S-video) and those with high-resolution output (1024x768 or higher).

• Refresh Rate– 20 to 30 Frames per second

• Zoom Lens

• Features

• Size

Common Features

• Zoom 4 to 16x zoom• Pan• Auto Focus• Capture images - single or timed continuous• Playback images - view saved images• Freeze image - irregular shaped object• Brightness• Remote control

Bells and Whistles

• Effects - change from color to black and white or negative

• Timer - time the image on the screen - countdown

• Reverse Image• Mirror Image• Night view - lower the frame rate• Download captured images• Optional microscope connections• Optional Interactive whiteboard connections

More Bells and Whistles

• Split Screen view - view both live and captured image

• Picture in picture - view thumbnail of a saved image with the “live” image in the background

• Presenter view - shaded exterior with clear view inside area

Why Should I Use One?

• How can they be used?– Case Studies– Using Document Cameras in the Elementa

ry Classroom– Document Cameras in the classroom– More Classroom Uses– More Case Studies

Web Resources

• 6 Things You Need to Know about Document Cameras

• LCD Projector Guide