GUIDE TO DISPLAY TECHNOLOGIES
Executive Vice President,
Noritake Company, Inc.
The basic characteristics of vacuum fluorescent display (VFD) technology continue to make it an attractive display for many applications in the medical field. Characteristics include high brightness, wide viewing angle, wide temperature range, long life, and relatively low cost (see Table I). The high brightness and wide viewing angle produce excellent visibility in low-light conditions and in situations in which the display cannot be viewed directly. The wide temperature range is suitable for emergency-vehicle and portable-equipment use. With the use of color filters, a wide selection of luminance colors is available in VFDs. VFD technology has become an essential display option for engineers involved in designing electronic medical devices.
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Table I. Operating parameters of typical VFD modules.
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Typical medical applications for VFDs include the following:
Smart Graphics Modules
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Figure 1. A cutaway view of a VFD graphics display module. (click to enlarge) |
The needs of medical design engineers have increased in recent years. Displays must accommodate more information and have the flexibility to use text and graphics at the same time. Also, with an increasingly global industry, displays must provide many language fonts in the same module to reduce development time and cost of products that are used in multiple countries. New sophisticated display modules provide intelligent built-in features in standard display modules that make designing more-flexible applications much easier (see Figure 1).
Standard smart graphic modules have the following built-in features:
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Figure 2. With proportional fonts, more characters can fit on one line. (click to enlarge) |
fit on a line and give a more attractive appearance (see Figure 2).
VFD with LED Backlight
Combination display modules are now available as well. These new modules offer the basic characteristics of a VFD graphics display with the bright, attractive background found in LED backlighting. These displays can produce many attractive and creative combinations of colors that can be controlled by the developer of the application.
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Figure 3. An LED backlight controls blue, green, and red in a single chip. (click to enlarge) |
The first standard graphic module is now available in a 140 X 16 resolution. The interface ports are parallel and RS-232. There are 21 LEDs (blue, green, and red in one chip) mounted inside the module (see Figure 3). The LED backlight is controlled by the general-purpose I/O. More standard modules using this technology will be introduced in the near future.
Graphic Development Kits
Graphic development kits provide great assistance to those who have little experience in driving a VFD display. They provide a way to test concepts and display formats without much effort. Kits enable designers to display the main built-in features of the display and record the code data that are sent to the display. Kits typically include a graphics display, a serial signal-and-power wire harness (RS-232 interface), and a power supply.
