A Good Display Is Hard to Define – Enter SID


What makes a good display? The electronic-display industry that SID supports is vitally interested in the answer to this question. In fact, this is not one question, but multiple questions, depending on who's asking. For the display researcher, the question might be, "What's the response time of this display?" For the display systems engineer designing a mobile-phone handset, the question might be, "What's the color gamut of this transflective display under daylight conditions?" For a consumer, the question is often, "What's the best deal for my next television?" For me, I've been wondering what the phrases "dynamic false contour" and "viewing freedom in 3-D displays" really mean.

Many of these questions do not seem to have quantitative answers, but many should, or already do. In some cases, the issue is simply finding a clear definition of a term. In other cases, one often finds that while it is possible to measure many aspects of an electronic display, there is no agreement on the exact measurement that should be used for a particular parameter. Perhaps, not surprisingly, one often finds that a particular group will define a measurement that shows off its display in the best light and highlights deficiencies in a competitive product.

One way to deal with these variations is to have broad agreement on a set of standards that can be relied on to provide a reliable way to define terms and make measurements. In this column, I'm proud to highlight some activities that SID is actively supporting in the world of electronic-display standards. While this effort is still very much in an intermediate stage, the outcome promises to serve all parts of the display industry by providing a set of reliable references on display performance.

The International Committee for Display Metrology (ICDM) is working to produce the ICDM Display Measurement Standard (DMS), a document for measurements of all types for displays. The goal is to produce a comprehensive use of procedures for use by the display industry. Today, many characteristics of displays are poorly defined, which leads to confusion at best and some serious misconceptions at worst. An industry as large and diverse as the electronic-display industry needs a set of accepted standards to enable a dispassionate comparison of different displays and their components.

The DMS is an ambitious effort and is targeted to contain several hundred of pages of display-metrology measurement instructions, technical discussions, tutorials, data tables, a glossary, a list of acronyms, and references. The principal goal is to provide a well-defined set of instructions on how to evaluate a display and quantitatively measure its characteristics. These instructions will be complete and clear, providing sufficient background so that the selection of criteria will make sense. Another goal is to put in place a common language that can be used by people evaluating displays, as well as by those who need to understand and evaluate those results.

Today, many display characteristics are measured in very different ways and produce very different results. These parameters are either poorly defined or are defined in such highly precise and technical language to be beyond the understanding of all but specialists in the field. A goal of the ICDM is to provide a reference guide that both simplifies and clarifies the choices available for characterizing a display. These references will serve both established and emerging display technologies, such as liquid-crystal displays, organic light-emitting-diode displays, and reflective "electronic paper" displays.

The ICDM is a committee that is part of SID, under the umbrella of the Definitions and Standards Committee. A more detailed description of the ICDM and the goals of the MDS appeared in the February 2008 issue of Information Display, though significant progress towards the DMS has occurred since that time. (This article is available in the archives section of www.informationdisplay. org.) Currently, the committee consists of about 130 people in the display industry, including some of the most preeminent experts in display metrology and evaluation, as well as representatives from most of the major manufacturers in the display industry.

The ICDM has a Web site that can be accessed at www.icdm-sid.org/. It also has a wiki under development at http://wiki.sidmembers.org/index.php?title=ICDM . The wiki is particularly interesting because it allows the greater SID community to add their expertise and know-how to the mix. If you would like to contribute to the effort, one way is to check out the wiki!

The ICDM is a great example of SID's ability to attract volunteers who are passionate about displays, donating their time and expertise for a worthy effort to promote the industry. So, a big salute to them, and please keep an eye out for the results of their efforts. Just don't expect an answer to the question, "What's the best deal for my next TV?" The ICDM deals primarily in display physics and not consumer psychology – maybe SID needs a parallel effort here with marketing professionals!

Paul Drzaic
Society for Information Display