Display Electronics: Complex, Yet Critical
by Lewis Collier
With the expected demise of broadcast TV and the need to allow my wife to tape "her shows" while playing chauffeur for the kids, we finally splurged for some new display electronics. No, not a new display, but a cable set-top box with an integrated DVR function. This, of course, led to a series of machinations regarding how to run the old (1 year is a long time in this business) 27-in. LCD TV with the newfangled box rather than (actually, while not losing) the ability to also tape with the "old-fangled" VHS. How ironic it was when I was asked to be the guest editor for the Display Electronics issue of Information Display while engaging in my own battles with similar demons.
As we all know, electronics affects every facet of display technology. From signal-input receivers (with all their noise and impedance-matching issues), through image processing, such as compression and display quality, to the synchronized symphony of pixel drive and illumination control, display electronics can be complicated. When setting up our new DVR set-top box, I discovered that our TV does not support any of the myriad remote-control codes. This was clearly an unexpected (and unnecessary) addition of complexity to the display processing chain. My wife, who is a self-proclaimed "non-techie," now completely understands how to use the DVR. I, however, remain at a loss as to why my TV doesn't respond to one of the hundreds of already defined codes or why there are hundreds of codes in the first place.
Soon after my entry into the display field, I often uttered my mantra of "I hate drive electronics" when faced with issues regarding rear-projection television (RPTV) electronics for driving microdisplays. I understood that the task at hand was hard, I just did not understand how hard. Years later, I have a better appreciation for just how much effort goes into bringing information-display electronics to life. I hope that the articles selected for this issue should help shed light on this issue for you, the reader, as well as showing ways in which the complexity problem can be solved.
In his article on "Image Enhancements in the Wavelet Domain," Barry Mapen of Alion Science provides insights into how wavelets can be used for video compression and how the compression processing can be used to reduce the processing power required to perform some of the basic image adjustments that all display products must provide. While demonstrated with the wavelet transform, these power-saving methods can be used with other compression techniques as well.
In "Design Considerations for LED Backlights," Suzanne Thomas and Stephen Soos of Applied Concepts help break down the requirements of LED lighting. By comparing the drive circuitry to the prevailing standard CCFL drivers, they provide a list of issues to be considered when designing or choosing LED drive electronics. The complexity of these challenges can be reduced by the choice of driver solutions. The drive solutions are not as easy as ordering one from a catalog, yet, but as LED back- lights become more ubiquitous, this day will come.
Display electronics is complex. We hope that you find the information in this issue insightful and relevant to your pursuit of understanding this complexity in display electronics.
– Lewis Collier