Rear-projection television

Rear-projection television (RPTV) is a type of large-screen television display technology that projects and reflects an image onto the back of the television screen, as opposed to direct-view television (DTV) sets that use a traditional cathode ray tube (CRT), or the more modern liquid crystal display (LCD) and light-emitting diode (LED) televisions that project light directly from the front. RPTVs are capable of supporting high-definition display resolutions and have been popular for home theaters due to their relatively large screen size for a lower cost than flat-panel displays.

History

Rear-projection TVs were most popular in the late 1990s and early 2000s before the widespread adoption of LCD and plasma flat-panel displays. The technology behind RPTVs has evolved over time, starting from CRT-based systems to digital light processing (DLP), liquid crystal on silicon (LCoS), and LCD-based projection. Despite their once-popular status, the demand for RPTVs has significantly declined due to the bulkiness of the units and the advancement in flat-panel technology offering better picture quality in a thinner form factor.

Technology

Rear-projection TVs use a projector embedded within the television set to cast images onto the back of a translucent screen. This method allows for larger screen sizes without the massive depth required by traditional CRT televisions. There are several types of projection technologies used in RPTVs:

• CRT-based RPTVs: The oldest form, using three CRTs (red, green, and blue) to project the image.
• LCD-based RPTVs: Utilize a small LCD panel and a light source to project the image.
• DLP-based RPTVs: Use a digital micromirror device (DMD) chip and a color wheel to create the image.
• LCoS-based RPTVs: Combine features of DLP and LCD, using liquid crystal chips and a reflective backing.

Advantages and Disadvantages

Advantages:

• Larger screen sizes available at a lower cost compared to flat-panel displays.
• Capable of high-definition resolutions.

Disadvantages:

• Bulky and heavy, requiring significant space.
• Viewing angles and brightness may be inferior to those of flat-panel displays.
• May require more maintenance, such as bulb replacements for DLP and LCD models.

Current Status

With the advent of affordable large-screen LCD and OLED TVs, the market for rear-projection TVs has nearly vanished. Manufacturers like Sony, Mitsubishi, and Samsung have discontinued their RPTV lines. However, some enthusiasts and home theater aficionados still use and maintain RPTVs due to their unique characteristics and cost-effectiveness for large screen sizes.

See Also

• Television technology
• High-definition television
• Digital light processing
• Liquid crystal on silicon
• Liquid crystal display
• Light-emitting diode