Monitors merit attention from CAD users

By Donald Jenner

Choosing a monitor is a matter of space, in two senses: How much real estate does the box require, and how much real estate does it give for work?

The second question is a matter of technology and an area where monitor makers compete. The first is entirely the province of the buyer.

Forget about 14-inch office-automation monitors; most graphics-computer users need more screen space than even a good 15-inch monitor affords. The choice is between some kind of 17-inch monitor and a 20-inch monitor. Each has advantages.

A 17-inch monitor will show an area defined by a diagonal of about 16-inch. It fits in a space not greatly larger than that of a 15-inch monitor (with about a 14.5-inch/diagonal display). A smart user sits about the same distance away ­ not less than 24 inches and not more than 30 inches. Allowing for usual chair placement and so on, a standard workstation area that is machine-height (27 inches ­ say, 68.5cm) and 36 inches (just shy of 1m) deep and twice that width, readily accommodates a 17-inch monitor. For folks moving up from 15-inch models, but not doing some serious rethinking of their office ergonomics, a 17-inch model is an attractive choice. It also saves money immediately in purchase price and in workstation rebuilding.

20-inch (and 21-inch) monitors ­ with diagonal viewing areas ranging from 18 inches to 19.5 inches ­ have a dramatically bigger space requirement. They are much taller, broader and deeper. They need to be viewed from further back. They weigh a lot more (have two people move these ­ or risk back problems or a hernia).

Plan on a desk space that is a good six inches to eight inches (15cm to 20cm) deeper. Make sure it is sturdier. Figure the monitor should sit back an at least that extra six inches from the user. This is a purely practical matter: It is wearing to be swiveling eyes back and forth to take in the whole image when working. The bigger tank needs a wider viewing angle, achieved by sitting back a bit further.

Accommodating a big screen like this is easiest when also reworking the entire workstation, or building from scratch.

The second element ­ how what you see looks, and how much can you fit on the screen ­ is more technical. "How much" is determined by the rated resolution of the screen in conjunction with the capabilities of the display hardware in the computer. "How it looks" is mostly dependent on the monitor itself.

The lowest-end graphics adapters commonly available today deliver 1024x768 pixel resolution, with a potential palette of 65,000 colors. Most display adapters used in serious graphics do better than that (see sidebar). A monitor paired with that, intended for use in a graphics environment, needs to support at least that resolution. Higher pixel resolutions ­ 1280x1024 for 17-inch monitors; up to 1600x1280 for 21-inch monitors ­ are commonplace.

The image needs to be sharp and as flicker-free as possible. Here's where technology comes into play.

The conventional picture-tube technology used a shadow-mask to break up light beams, so that each bit of light hits a phosphor dot and produces illumination. The "dot pitch" figure often found in monitor literature reflects the size of the hole in the mask. The smaller the dot, the sharper the image.

Sony developed a better way to do this. Called an "aperture grill", light is painted in vertical stripes. The result is a crisper picture, equivalent to a finer dot-pitch (a measure which ceases to have real meaning in this case). Moreover, less interference with the light coming to the screen seems to explain the noticeably brighter image associated with Sony's Trinitron tubes. Many companies have adopted aperture-grill technology in at least their up-scale product lines.

Another Sony innovation, now seen in monitors from other companies, is the use of a single light gun. Sharpness is also a factor of the focus of all three color elements. With three light sources, all three have to be focused and calibrated to work together; with one gun, there less to go wrong. Again, the result is sharper, brighter images. Higher resolution without these technologies is less readily achieved ­ and doesn't look so good.

Flicker is the last of the important element: This is a matter of scan-rate. Obviously, the less the eye senses and responds to the line-by-line scanning of the image as it is constantly refreshed on-screen, the less sense of flicker it will have and the happier you will be. The larger the screen, and the higher the resolution, the faster the scan-rate needs to be to accomplish this sense of flicker-free display. A single-gun, aperture-grill design works better for this aspect of the problem. Notice that most manufacturers' monitors will support a higher resolution with a slower scan rate, but will recommend a lower resolution with a higher scan rate as optimum. This is the trade-off.

Sony, obviously, has a strong presence in the monitor market. The company markets a complete line of graphics display monitors based on its Trinitron tube. Trinitron tubes are also featured in other makers' products.

Sony's aperture-grill models have two classes of competitor: First, old-line brands ­ Mitsubishi & NEC, for example ­ have advanced color display technology, using variant designs. Mitsubishi's Diamondtron tube uses aperture grill design with what the company calls its "dynamic beam forming" gun which, the company claims, produces a sharper image at the edges of a flat, square screen. When monitor screens were curved, the beam could hit all edges evenly; flat, square screens mean that the edges are a bit further from the "muzzle" of the light gun than is the screen center. Focus becomes an issue ­ again, something easier to correct in an aperture-grill, single-gun design.

Compaq, known as a high-end desktop computer-maker and seriously interested in owing a share of the Wintel Workstation market (see CAD SYSTEMS, June 1997), has introduced a new generation of Sony Trinitron-based large-screen monitors. The P110 21-inch monitor and the P1610 24-inch monitor deliver high resolution (respectively, 1600 and 1900 pixels horizontally; both supporting 1200 pixels vertically) on a flatter screen using a new generation of Trinitron tubes for which Compaq has an exclusive deal. While Trinitron tubes have always been fairly flat vertically, the tubes have curved more horizontally than later-generation aperture-grill designs. These new tubes represent Sony's latest and best. Compaq is commanding a premium price for these monitors.

The "tier-two" class consists of companies known better for supplying local integrators. Viewsonic and CTX are good examples. These companies have emerged as new major players, partly because of quality but more especially because of aggressive pricing.

Companies mentioned in this story:








Number Nine

Viewsonic is more "mainstream" ­ to the point where the company actually has a subsidiary product brand, Optiquest", for low-cost offerings. Viewsonic's own "graphics series" and "professional series" monitors merit attention from CAD users. Both model lines include standard shadow-mask and aperture-grille, 17-inch through 21-inch designs. A Viewsonic graphics series 17-inch shadow-mask design comes in between Cn$919. and $Cn$989. (there appear to be small feature differences, but substantially identical display capabilities in these models). The comparable aperture-grille model (with marginally less on-screen territory but the brightness and sharpness advantages explained above) costs about Cn$150. more. A 21-inch model costs between Cn$2419. And Cn$2519.; the company's 21-inch Optiquest model has a more affordable Cn$2129. price tag.

CTX monitors are most commonly encountered in systems from budget integrator houses. The company has launched a program to gain wider market awareness. Most of these products are upper-end shadow-mask designs, with a short list of Trinitron-based designs. CTX is the company behind a lot of proprietary brands; the company's Taiwan parent makes monitors accompanying many a well-known machine.

A good display adapter is good for your temper

A good monitor is good for your eyes. A good display adapter is good for your temper. These are two parts of the same puzzle. A very interesting example of the latest-and-greatest comes from Number Nine, a company with a long history of innovation in best-of-breed graphics display hardware.

The Revolution 3D display adapter merits attention for four reasons:

It is very fast. Put aside benchmarks (if you want them, go to the Number Nine website); what interests me is front-of-screen performance. With the Revolution 3D, one more blockage is removed from the put-it-up-fast process. I have seen this board deliver superior walk-through performance.

Number Nine is delivering an AGP version of this board. AGP is Intel's new specification for share-memory access for central and graphics display processors. Effectively, the image doesn't have to be moved across the buss from central memory to display memory. The graphics display accesses the central memory directly. This is a low-cost time-saver proven in workstation systems like SGI's remarkable O2.

In many systems, there is a trade-off: Put in a 3D graphics display system, and watch 2D performance suffer. Even Number Nine was pleasantly surprised when independent tests showed that this is not the case for the Revolution 3D.

The Revolution 3D is remarkably affordable. Forget about US$2,000. graphics display cards. This one will do what you expect to get from a GLINT-based solution, at a quarter of the price for some of those higher-end solutions.

Number Nine has done this with a design of their own that is sufficiently solid and supportable that mainline (e. g., NEC) and speciality (e. g., SAG/ECE Electronics) system integrators are adopting it as the standard for high-end boxes. Couple one of these with a good monitor, and you may keep the display system longer than you do the rest of the computer.