Understanding 3LCD Technology

by Sharon Lobo    Oct 01, 2009

In a span of less than 20 years, the global projectors industry has become a multibillion dollar market. In 2006, world-wide value of the projection display market stood at $18 billion. This is expected to grow to about $30 billion in 2013. The three major technologies currently used in projectors are

  • 3-Chip Liquid Crystal Displays (3LCD)
  • Digital Light Processing engines (DLP)
  • Liquid Crystal-On-Silicon devices (LCOS)

With more than 60 percent of the world-wide projector market share, 3LCD leads the race followed by DLP and LCOS. Since 1993 an estimated 13.2 million 3LCD projectors have been sold. Recently Epson, a manufacturer of 3LCD projectors, held an exclusive 3LCD ‘Technology Forum’. At this forum, Tim Anderson of the 3LCD group, along with Ng Njee Khiang of Epson, demonstrated the benefits of 3LCD projectors over DLP projectors. The following article reveals the working and the benefits of the 3LCD technology.

Working of 3LCD projector

A 3LCD projector system uses a combination of mirrors to break the white light from the lamp into red, green and blue light (RGB - 3 basic video colors that combine to form white color). These three-colors are shone through its own LCD chip, where each chip forms an image of liquid crystals of the electrical signal they receive.

The three colors are then recombined by a dichroric prism (A multi-faceted crystal that splits light into two beams of differing wavelength or color) and passed through a projection lens. The projection lens, in turn, expands the image and directs the light onto the screen or viewing surface. This results in smooth-moving images with rich and full color, since all three basic colors are included in each pixel of the projected image at all times.

 


  Working and components of a 3LCD projector

3LCD projectors overcome screen-door effect and provide HD display resolutions

Earlier 3LCD projectors had an limitation known as the ’screen-door’ effect - where images look faded, as being viewed through a screen door. The cause of the ’screen-door’ effect has been attributed to the lower resolution amongst previous SVGA projectors which have only an 800×600 pixel resolution. This low resolution results in wider inter-pixel gaps and pixel visibility that causes fading and graininess of the images.

However, through production of higher resolution 3LCD projectors this effect has been effectively addressed. The current resolution of 3LCD projectors range from XGA (1024×768 or 589,000 pixels) to Wide XGA (WXGA) (1280×720 or more than 1 million pixels) and High Definition Television (HDTV) display resolutions (1920 1080, or 2,073,600 pixels).

3LCD Offers High Contrast Ratio

3LCD projectors are reputed for high ANSI lumens in both White and Color Light Output. Weak contrast ratio causes blacks to look gray in images. This causes weak distinctions in black gradations. Distinct gradations are however, important in the construction of shadows and shades of gray that results in visual realism - an essential quality for home theater projectors.

Experts found that higher contrast ratios (i.e. 2500:1) in projectors fall dramatically into standards irrelevant to the human eye (i.e. 10:1) under ambient levels expected of classrooms and business environments. The study asserted that the contrast ratio of a digital projector in a classroom or business environment has been proven irrelevant due to the high degree of ambient light where the projector is performing (unlike the total darkness in a home theater setting).

Manufacturers of 3LCD Projectors

There are numerous manufactures of 3LCD projectors, these include Epson, Hitachi, Mitsubishi, Toshiba, Panasonic, Avio etc. of which Epson also manufactures its own 3LCD Thin-Film-Transistors (TFT) and projector Lamps, known as
Epson Twin Optimized Reflection Lamp (E-TORL). As a result Epson projectors not only provide the benefits of the 3LCD technology, but their E-TORL results in lower power consumption, cooler operation and longer operational life compared to conventional projector lamps.

For more details on 3LCD technology and the projectors that use this technology, visit www.3lcd.com