General Digital

Published October 19, 2012

Before we reveal the five questions that you need to ask yourself when choosing a video controller that best suits your LCD monitor and application, let’s start with question number zero: What is a video controller?

To answer that, you need to know more about the computer’s video card. The video card inside of a computer serves to generate images that are output through a video connector and video cable, and appear on the screen (display). Though we will not be exploring the intricacies of how the video card accomplishes this (for which you are thanking me, no doubt), it is important to recognize that a computer would be useless without the video card translating data into visual information.

Perhaps as part of its inclusion in the Witness Protection Program, the video card goes by a variety of names. However, the terms ‘video card,’ ‘graphics card’ and ‘graphics board’ are common industry accepted labels for the circuit board that controls video on your computer. For the purpose of this blog, we will stick with the term ‘video card.’ Some of the most common video card brands in use are ATI, NVIDIA, and EVGA, though there are plenty more available.

Now, back to the video controller. Internal to any LCD monitor is an LCD video controller that converts analog or digital video signals sent from the computer’s video card into the proper digital signals required to drive, or operate, the display (typically LVDS or TTL digital signals). The video controller, which is more formally referred to as an LCD panel interface board or LCD interface controller, goes by a variety of other names such as ‘LCD controller,’ ‘LCD video controller,’ ‘display controller,’ and even ‘display adapter.’ To keep it simple and consistent during this blog, we will just use ‘video controller’ (“Whew!,” you say as you wipe your brow).

It is the video controller that enables the LCD monitor to function as a direct replacement for the traditional CRT monitor (which also has a video controller). It provides intuitive operation of its controls and calibration through the use of push buttons and a series of on-screen menus.

So, what are the questions you need to ask yourself in choosing from the plethora of available video controllers?

1. What is the size of the display or monitor that will be used with the video controller? The diagonal measurement of the LCD viewing area is the first important factor to note.

2. What is the resolution of the display that will be used with the video controller? This is also called the ‘native resolution,’ which is the number of horizontal and vertical pixels on the display (e.g., 1920 x 1080).

3. Which specific video inputs will be needed (analog, digital, composite, etc.)? Will you only need analog RGB, or Sync-on-Green VGA and DVI-D, or HDMI, NTSC and RS-170? This is perhaps the most important question of all.

4. Are there any additional features needed (picture-in-picture, picture-by-picture, gamma correction, resolution scaling, image inversion, zoom, serial remote control, etc.)?

5. Are there any additional thermal or other environmental requirements? Though made of similar components serving similar purposes, video controllers are not created equally. They can be made to withstand high temperatures and humidity, severe vibrations and shock, and even strong magnetic fields such as those found in MRI (Magnetic Resonance Imaging) rooms.

Once you have determined the answers to these questions, you will have gathered the facts necessary to make an informed decision. If you need additional assistance not provided here, please feel welcome to contact us.

Next choice: power supplies! Check back soon for more information on how to select the right power supply for your application.

Published May 15, 2012

LED (Light Emitting Diode) backlight design provides advantages that can be highly beneficial in a variety of applications and industries. LEDs offer longevity (50,000 hours minimum), far greater resistance against shock and vibration, reduced power consumption and heat emissions, brighter intensity and more precise control of that intensity. Light from the LEDs in an LCD (Liquid Crystal Display) screen is diffused to illuminate the viewing area evenly.

Two different configurations exist for LED backlighting: array and edge-lit. Array lighting–in which LEDs are mounted uniformly behind the LCD screen to distribute light evenly–offers the advantage of increased contrast, resulting in greater depth of color. Edge lighting places the LEDs on the sides of the screen (usually the top and bottom) rather than behind the screen, which allows for a thinner package and reduces power consumption; this comes at a cost of a slight deficit in uniformity.

Although most commercial LED rails for LCD displays are designed to be driven serially, General Digital employs a serial-parallel design philosophy, whereby we drive the LEDs in groupings of three or four. The advantage to this method is that instead of rendering the entire rail inoperable, a single LED failure will only affect its immediate grouping (soft failure). This means that singular or multiple LED failures will not render the monitor inoperable, and in most cases will still provide a very uniform backlight–essential for mission critical applications.

Also of interest to military and heavy industrial needs is the fact that LEDs are ideally suited to sunlight readable and NVIS (Night Vision Imaging System) applications. Their longevity, superior brightness control, and resistance to shock, vibration and weather extremes makes them an almost obvious pick for use in harsh environments. Other LED backlit display benefits include reduced EMI emissions, operation at low temperatures (-40° C), and virtually instantaneous full brightness for those mission critical situations. Other applications can benefit from LED backlighting, such as digital signage, construction, and aviation, to name a few examples.

Published April 18, 2012

For millenia, most of man’s activities were confined to daylight hours. With the advent of night vision technology, man can now accomplish many daylight-only tasks in the dark.

Night vision goggles (NVG) work by taking low level incoming visible light and non-visible infrared (IR) light and converting them both into electrical energy (electrons). Through a rather complex process, these electrons are then multiplied and converted back into light, which allows an NVG wearer to see in pitch black conditions. Standard CRT and LCD monitors using CCFL (Cold-Cathode Fluorescent Lamps) backlights interrupt the view of a person equipped with NVG because these monitors emit high levels of IR radiation, specifically the kind that’s amplified by night vision goggles. What results is a phenomenon known as “blooming” (washed out screen), as well as oversaturation, which renders the user effectively blind. This is true even if the monitor is in the proximity of the user but not in their direct field of view.

NVIS (Night Vision Imaging System) compatible displays are not born, they’re made. At General Digital, we re-engineer existing display hardware to virtually eliminate the emission of high levels of IR radiation. To accomplish this, entirely new backlighting systems are sometimes installed (CCFL or LED). We can configure an LCD monitor to be NVG compatible in two distinct ways. One method allows an NVG user to easily view information on a display screen, as well as their surroundings, while using the night vision goggles. Another way completely blocks all light from being visible to the goggles, while still visible to the naked eye.

Read more about NVIS compatibility with LCDS and how night vision goggles work.

General Digital offers many sizes of ruggedized monitors with NVIS capability that meet MIL-STD-3009. A sampling is listed on our NVIS for LCD Monitors page.

Published January 26, 2012

There are few things more heartrending than buying liquid crystal displays, ensuring their safe transport, and handling them with extreme care, only to damage them irreparably during the mounting process. Because a liquid crystal display (LCD) is extremely sensitive to mechanical stress and susceptible to electrostatic discharge (ESD), careful considerations must be given to it when mounting. This is especially true when the display is optically bonded from the outside of the display frame. Failure to take proper precautions can result in panel failures, including permanent damage of circuits due to electrostatic discharges, brightness hot spots, delamination of the bond in ambient or elevated environments, cracking of the cover glass, and cracking of the LCD, among other catastrophes.

Though LCDs are rather fragile, simple yet effective practices exist that will enable you to complete the mounting project with little complication. First, the optically-bonded products must be handled with both hands from opposite edges of the display frame. Long before ever mounting the optically-bonded LCD, damage can occur through improper handling. It is also very important to note that, as with all electronic devices and components, proper ESD protection practices must be followed accordingly. An electric shock can easily sound the death knell for your optically-bonded LCD.

The mechanically stress-sensitive nature of liquid crystal displays requires customers to take special precautions when designing the mounting details for any given applications. As a general rule, the panel should be mounted evenly and reliably using the panel manufacturer’s mounting points. Absolutely no excessive stress should be applied to the optical surface and other parts of the the frame. When mounting the panel, ensure that it is in the correct position first, tightening the screws gently and evenly. It is highly recommended that a torque wrench be used to avoid over/under tightness.

Following these simple instructions will go a long way toward helping you complete your project without costly and time-consuming repairs.

Published Febraury 17, 2011

aka, How to Clean an LCD Monitor 101

Cleaning an LCD Screen

If you’re anything like me, you’re never thrilled with the smudges that show up mysteriously on your monitor. I’ve never quite figured out from where those smudges come. I mean, I’m pretty sure I’m not putting them there. What purpose would be served by wiping my computer screen with a sweaty palm?  I’d be willing to wager that, given the right tools, a CSI unit could uncover some interesting details about a person’s life just from the contents of those smudges and fingerprints.

Well, your friends at General Digital’s Optical Bonding Laboratories are here to clear your murky view…and educate you a bit, as well. We’re going to help you wipe away your “history” the way the professionals do. Trust me, this is a little more complicated than dipping a Kleenex in a cup of Perrier.

As with any other great endeavor, one must start with the proper equipment. Latex gloves are absolutely essential:  use the ones that are oil-free and without powder. Be sure to test a small area in the corner of the screen to make sure that the gloves don’t leave any residue. You’ll also need filtered ionized air from an oil-less compressor or simply canned air, the type you can buy at your typical electronics or office supply store. And don’t forget the lint-free wipes (what are commonly referred to as cleanroom wipes) necessary to actually remove any debris from the surface.

You’ll need a good cleaning agent to wrest those smudges from your screen. Here at General Digital, we use Uvex® Clear; a fairly common cleaner in the industry, Uvex® Clear is an alcohol- and silicone-free lens cleaning solution. Many times, Uvex® Clear will be all you need to remove smudges and stains. When we encounter a stubborn stain, we will then upgrade to isopropanol, which gives a little more bang for the buck. A good rule of thumb is to start with Uvex® Clear and work up from there.

Finally, all that is left is the execution of this endeavor. After folding the lint-free wipes in half twice, spray the wipe with the cleaner. Never spray the screen directly. You’ll want to lightly wipe the screen from top to bottom. Because the height of the screen is a shorter distance than the width, you are less likely to re-deposit debris onto the screen. Also, you’ll want to wipe the screen at a rate that is slow enough to wipe away any foreign particles but fast enough not to leave smudges in its wake.

Although this technique works for LCDs, plasmas, and touch screens, as well as most other substrates, it may take a few attempts to clean the screen. With each swipe, be sure to use a clean portion of the wipe. The last thing that you want to do is reintroduce debris to the screen. After the careful removal of dust, prints, and smudges, there is only one thing left to do. Use a stream of compressed gas to remove any lingering debris. You will discover a gleaming ‘new’ screen awaits you!