During the past two years, the price tag for Sony's acclaimed SXRD display technology has dropped from $30,000 to $13,000 to a much more wallet-friendly $4000 (with the 50" KDS-R50XBR1, shown).

For me, one of the real high points of the 2005 Consumer Electronics Show was seeing Sony's 70" Qualia™ 006 rear-projection TV in action. That $13,000 set uses a Sony-developed projection technology called SXRD — Silicon X-tal (Crystal) Reflective Display. Watching high-definition movie clips fed from a prototype Blu-ray player, I saw exceptional picture clarity and detail, with vivid colors and a seamless overall look that reminded me of the finest tube-based TVs.

Until now, the only other way to experience SXRD has been via Sony's $30,000 Qualia 004 front projector, which has established a new reference for projector picture quality. When I learned that Sony was introducing 50" and 60" Grand Wega™ SXRD TVs with full 1080p resolution priced more in the mainstream of digital big-screens (like DLPs), I wondered how much of the SXRD magic Sony could preserve in models priced much lower.

Since I recently reviewed Samsung's 50" HL-R5078W DLP TV, which is also a 1080p design, I felt I had a handle on the considerable improvements in picture quality that 1080p provides compared to the more common 720p sets. The Samsung's bright, extraordinarily sharp picture had set the bar pretty high. Would the Sony be able to meet or even exceed its performance?

How SXRD works

All of Sony's previous Grand Wega big-screen TVs have been based on LCD display technology. SXRD, on the other hand, is a refined variation of LCoS (Liquid Crystal on Silicon) technology. Both types create images by manipulating microscopic liquid crystals. But here's the key difference: LCD is a "transmissive" technology where light passes through the image chip, while SXRD is a "reflective" technology that sandwiches a layer of liquid crystal between a cover glass and a highly reflective mirror-like surface patterned with pixels. Reflective displays such as LCoS and SXRD (and DLP) use the light from the TV's projection lamp more efficiently, resulting in higher picture brightness and contrast.

The other main LCoS/SXRD advantage is having the circuitry that controls the pixels positioned behind the pixel array and out of the light path, rather than on the array as with LCD. That permits SXRD pixels and the spaces between the pixels to be much smaller, resulting in pictures that are detailed yet extremely smooth and natural looking. SXRD is a "3-chip" system — there are three SXRD image panels, one each for red, green, and blue. Each panel has 1920 x 1080 pixels, allowing 1080i HDTV signals to be displayed at full resolution.

So, SXRD has some great numbers, but how do they translate to what you see on the screen? Here's my quick take on the main factors determining image quality:

• Resolution: While SXRD is not the only display technology to deliver 1920 x 1080-pixel resolution, SXRD has the highest "pixel density" and the smallest between-pixel spacing of any TV available. From a normal viewing distance, images looked remarkably smooth and seamless, and even with my face just inches from the screen, I couldn't see any sign of grid-like pixel structure (often called the "screen door effect").
• Contrast: The SXRD chips in the KDS-R50XBR1 are the latest generation, and offer higher contrast than the chips in the Qualia 006 (5000:1 vs. 3000:1). Contrast is further enhanced through the use of a motor-driven "dynamic iris" (explained below). The Sony's contrast and black level performance equalled the best I've seen from a rear-projection set: Samsung's 50" HL-R5078W.
• Color: Because there are separate image chips for red, green, and blue, SXRD provides continuous color. Compared to a rear-projection TV that requires a fast-spinning color wheel, SXRD puts more color information on the screen at any given instant. Colors look rich and deeply saturated. In fact, the color occasionally seemed a bit too lush, but while I wouldn't swear that it was always 100% accurate, it was always 100% eye-pleasing.
• Motion: Digital displays (LCD, plasma, SXRD/LCoS, DLP) build images out of pixels, and the ability to produce smooth, clean motion depends on the display's "pixel response time" (the time it takes for one pixel to switch from fully on to fully off). Sony's current LCD-based Grand Wegas have a pixel response time of 12 milliseconds, which is generally considered excellent. SXRD image panels use a much thinner liquid crystal layer, which enables a lightning-fast response time of just 5 milliseconds. You might not think the human eye could detect a difference of a few milliseconds, but it really makes a difference in how believably a screen can display fast-motion material like sports. I never saw any trace of motion smearing even while watching college football on ESPN HD.

The motorized iris includes a circuit that samples the brightness level of the video signal and responds instantly to deliver the best possible contrast and black level.

A "dynamic iris" improves black level and contrast in the blink of an eye

Like other top-performing 1080p big-screen TVs, the KDS-R50XBR1 (and its big brother, the 60" KDS-R60XBR1) employs a "dynamic iris" feature that constantly monitors and adjusts the amount of the lamp's light that passes through to the screen. Sony's approach gives the user the ability to fine-tune iris operation, providing a more customized viewing experience. On the KDS-R50XBR1, the dynamic iris is part of Sony's Cinema Black Pro system, which works in two ways:

• Iris Control: This lets you enlarge or reduce the iris' overall opening based on the amount of light in your viewing area. You can increase the overall brightness level for watching sports during the day, then reduce the brightness for a more cinematic look when viewing DVD movies at night. You can choose from 5 settings.
• Advanced Iris: This feature, which is also user-adjustable, includes a circuit that samples the brightness level of the video signal and automatically adjusts the iris opening on the fly to optimize brightness, contrast, and black level on a scene-by-scene basis.

The dynamic iris is extremely effective, and most viewers will never even be aware of its operation. Blacks were very deep without sacrificing details in dark or shadowy scenes. This has been an area where CRT-based TVs have typically outperformed digital displays, but I think even the most demanding videophiles will be impressed by the way this Sony handles dark and high-contrast scenes.

Now that you have a feel for what makes the KDS-R50XBR1 tick, how does it look? Read on.