Slide projector

From Free net encyclopedia

A slide projector is an opto-mechanical device to view photographic slides. It has four main elements: a fan-cooled electric light bulb or other light source, a reflector and "condensing" lens to direct the light to the slide, a holder for the slide and a focusing lens. Light passes through the transparent slide and lens, and the resulting image is enlarged and projected onto a perpendicular flat screen so the audience can view its reflection. Alternatively the image may be projected onto a translucent "rear projection" screen, often used for continuous automatic display for close viewing. This form of projection also avoids the audience's interrupting the light stream or bumping into the projector.

Slide projectors were common in the 1950s and 1960s as a form of entertainment; family members and friends would gather to view slideshows.

In-home photographic slides and slide projectors have largely been replaced by low cost paper prints, digital cameras, DVD media, video display monitors and digital projectors.

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