Cheap trick: Andy Wilson, a Microsoft researcher responsible for developing Surface, shows off LaserTouch, a low-cost multitouch system that can transform any display into a touch screen.
Microsoft
A new system from Microsoft turns virtually any surface into a multitouch display.
The multitouch screen is certainly having its day in the sun. Apple's iPhone and iPod and Microsoft's touch-screen table, called Surface, all illustrate the concept in slick ways. And at a recent conference, Bill Gates and Steve Ballmer showed off Windows 7, a forthcoming operating system that supports multitouch. But the capabilities of today's multitouch software are still somewhat limited, and researchers and engineers aren't yet sure how best to exploit large displays. Recently, however, Microsoft introduced a new multitouch platform, called LaserTouch, which includes hardware that's cheap enough to retrofit any display into a touch screen. The software giant believes that by providing inexpensive multitouch hardware, researchers will be more inclined to experiment with different form factors and develop interesting software.
LaserTouch is a system built on the cheap: the hardware only costs a couple hundred dollars, excluding the display--which can be a plasma television or overhead projector, for instance--and the computer that runs the software. Unlike Surface, which uses a camera within the table to detect touch and a rear-projection system to create the images, LaserTouch uses a camera that's mounted on top of the display. Two infrared lasers, with beams spread wide, are affixed at the corners, essentially creating sheets of invisible light. When a person's finger touches the screen, it breaks the plane of light--an action that's detected by the camera above.
One of the main differences between Surface and LaserTouch, says Andy Wilson, one of Surface's developers, is that you can use LaserTouch on high-resolution displays. These displays lend themselves nicely to graphics applications, such as photo and video editing. And since LaserTouch can be fitted to any type of display, Wilson adds, it could be used for office applications such as presentations.
While multitouch interfaces have gotten a significant amount of attention recently, it's certainly not new technology. Researchers have been playing around with touch screens in labs for decades. But only when the iPhone illustrated a practical use for the technology did excitement build, says Scott Hudson, a professor of computer science at Carnegie Mellon University. "The iPhone has given [multitouch] a whole lot of visibility at present," he says. "I think it's reached the level of general public interest so that a lot of manufacturers are thinking that it has potential."
Say goodbye to the mouse and hello to augmented reality, voice recognition, and geospatial tracking.
LCDs use only one-third to one-half the electricity of their CRT counterparts. They are much easier on the eyes, take up 90% less space, and only weigh a few pounds. They also emit far less low-frequency radiation than CRTs. This makes LCDs a great choice for nearly everyone, and ideal for people who work USB Monitor all day in front of the screen. Colors may change hue as one moves to the outer limits of the viewing angle, particularly on displays with narrow viewing angles and low contrast ratios. For this reason graphics professionals that require exacting color consistency regardless of viewing angle generally use CRTs, though LCDs have improved in this regard.
The viewing angle is an especially important consideration if you plan to have multiple people viewing the LCD monitor at any given time. There is a vertical and a horizontal viewing angle specification, which refers to the degree you can stray from dead center before the picture starts to wash out. High contrast levels usually go hand-in-hand with wider viewing angles. Many recommend a viewing angle of at least 140 degrees horizontal and 120 degrees vertical. The wider the viewing angles, the better.
Response time is measured in milliseconds (ms) and refers to how long it takes pixels to turn from completely white to black and back again. Smaller values represent a faster response time and are more desirable, especially for gaming or viewing video. If the response time is slow, "ghosting" or "trailing" can occur with fast-moving images, as repaints of the screen overlap. A maximum response time should be no more than 25ms for general use, and 17ms is better. Many gamers report no ghosting using an LCD monitor with a response time of 16ms or less.
An LCD monitor comes in standard sizes from 15-inches to 21-inches, and larger. The viewing screen is the Touch Screen LCD Monitor same size as the rated display, unlike CRT monitors. Therefore a 15-inch LCD will have a 15-inch viewing screen.
LCD displays were used on laptop computers before the technology improved enough to make the jump to desktop monitors. An LCD monitor consists of five layers: a backlight, a sheet of polarized glass, a "mask" of colored pixels, a layer of liquid crystal solution responsive to a wired grid of x, y coordinates, and a second polarized sheet of glass. By manipulating the orientations of crystals through precise electrical charges of varying degrees and voltages, the crystals act like tiny shutters, opening or closing in response to the stimulus, thereby allowing degrees of light that have passed through specific colored pixels to illuminate the screen, creating a picture.
As LCD technology evolves, different techniques for producing color emerge. Active-matrix or TFT (thin film transistor) technology produces color and images as sharp as any CRT and is generally considered superior to passive-matrix technologies.
Important specifications to consider when shopping for an LCD monitor include contrast ratio, brightness (or "nits"), viewing angle, and response time.
Contrast ratio relates to the display's comparative difference between its brightest white values and its darkest black values. A higher contrast ratio will have truer colors with less "wash out." The standard offering for lower end models is commonly 350:1. Many experts recommend a contrast ratio of 500:1 or better.
An LCD monitor is brighte r than a CRT, giving the consumer little reason to hunt for an especially bright model. Brightness is measured in nits, or one candela per square meter. Anywhere from 250 - 300 nits is standard. If they are much higher you'll likely end up adjusting the brightness way down.
LCD digital interface is technically described as "standing above the crowd"
Interfaces. LCD digital interface is technically described as "standing above the crowd." In theory, the liquid crystal display is a pure digital device, the host computer should also be used to connect digital interfaces. Advantages of using digital interface is self-evident, first of all reduce the analog-digital conversion process in the signal loss and interference, the corresponding reduction of the conversion circuit and components, followed by the clock frequency is not required, the adjustment vector. But now on the market of LCD monitors, most are based on the analog interface, the existence of signals susceptible to interference Touch Screen Panel , the display needs to join the ADC internal circuitry, can not be upgraded to a digital interface and so on. And, in order to avoid flickering pixels, must be the clock frequency, vector and analog signal exactly. In addition, the liquid crystal display digital interface has not yet formed a unified standard, with a digital output video card in the market are rare. Thus, the key advantage of LCD is difficult to give full play. For now, the result is often ahead of consumer spending at a higher price to go by.
Small viewing angle. Early visual yaw angle LCD display only 90 degrees, can only watch from the front, viewed from the side there will be greater brightness and color distortion. Now the market is generally deflection angle LCD display visible 140 degrees, is enough for personal use, but if several people simultaneously watch, distortion of the problem emerged.
Response time too slow. LCD response time is a special indicator, referring to the display each pixel of the input signal reaction speed. Short response time, motion picture is displayed when the phenomenon does not produce image smearing. This is playing games, watching video when fast action is important. Fast enough response time to ensure the continuity of the screen. Present, there is a general liquid crystal display, response time is quite different than before the break, usually around 40ms. But still can not meet the high quality 3D games and DVD movie playback requirements.
Brightness and contrast low. As the liquid crystal molecules are neither light, therefore, need to rely on external light source LCD auxiliary light. Some manufacturers standards and practical standards for the parameters Touch Screen TFT LCD Monitor there is a gap. Here to explain is that some small-sized liquid crystal displays in the past were mainly used in notebook computers, two-light adjustment, so they are not very good brightness and contrast.
Maintenance problems. LCD glass commonly used materials, it is easy to break, plus each pixel is very small, often result in broken behavior of individual pixels, commonly known as "dead pixel." This is not maintenance, need to replace the entire screen, while the price is often very expensive to replace.
The strength of LCD is that it's lightweight and easy to environmental protection, eye protection. However, because at this stage of LCD products such defects exist, can not meet all the needs of consumers. Product technology in this context, the user should not blindly follow fashion trends, but to recognize their needs and product features to make objective and practical choice.
LCD common faults
1, the water ripples and Huaping problems arise
The first thing to do is carefully check if there computer peripheral sources of electromagnetic interference, and then replace a graphics card, or receipt of another computer monitor, video card itself does not confirm the problem, and then adjust the refresh rate. If you exclude the above reasons, it is possible that the quality of the LCD monitor problem, such as the thermal stability of the bad issues. There is a liquid crystal display water ripple of the more common quality problems, they can not solve, the proposed replacement or repair as soon as possible.
Some LCD monitors will appear at startup Huaping problem, gives the impression as if there are high-frequency electromagnetic interference, like writing on the screen is fuzzy and jagged. This phenomenon usually is due to no digital interface cards, and through an internal digital / analog conversion circuit and the VGA connector on graphics card. Although this form of connection to solve the problem of signal matching, but it brought susceptible to interference and distortion problems arise. The reason is mainly because the LCD display itself is difficult and the input clock frequency analog signal synchronization clock to keep one hundred percent, especially in the analog sync signal frequency of the changing times, if the time synchronization circuit liquid crystal display, or sync with the video card signal transmission line connected to a short circuit occurs, poor contact and so on, can not be promptly adjusted to maintain the necessary follow-up to sync relationship, it would appear Huaping problems.
2, display resolution is set incorrectly
Because LCD and CRT monitors display different principle, it belongs to a direct one 7 Inch Touch screen VGA Monitor correspondence of pixels displayed. Work under the best resolution of the LCD to display graphics output of the analog signal through the processing, transformation to the specific address information (the pixels on the screen of the absolute address) of the display signal, and then into the LCD panel, directly to the display signal added to the corresponding pixel on the drive pipe, some with memory addressing and write similar. So LCD screen resolution is not arbitrarily set, but the traditional CRT monitors support for the resolution of the more flexible. LCD can only support so-called "real resolution", and only real resolutions to show the best image. When set to true resolution other than resolution, generally by increasing or reducing the scope screen, display remains the same, more than some of the black handle. Such as liquid crystal displays working in low resolution 800 * 600 when the pixel if the display is still one correspondence with the display, then it can only screen in the center of the screen narrow the center of that 800 * 600 pixels to display, although picture is still clear, but the display area is too small, not only feel uncomfortable but also for expensive liquid crystal display panel is a tremendous waste. Another interpolation method can also be used, whatever remains full screen resolutions, but this time displayed is compromised. In addition, LCD refresh rate settings and the picture quality to a certain extent. Friends according to their actual situation may be appropriate to set the refresh rate, normally set to 60Hz or better
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
This document is part of the “How-To Guide for Most Common Measurements” centralized resource portal. This tutorial provides a detailed guide for measurement and device considerations to take temperature measurements using thermocouples. Get an introduction to thermocouples, which are inexpensive sensing devices widely used with PC-based data acquisition systems. Also review some specific thermocouple examples and learn how thermocouples work and ways to integrate them into a data acquisition measurement system.
View full PDF >
Listen to story > 
Our list of the 50 most innovative companies, including the following:
On Twitter
Become a Fan on Facebook
Subscribe to the Feed
Shiladie
56 Comments
Science world
Science world is a local science museum/center, and I remember playing with an old touch screen monitor there 10+ years ago and wondering why they weren't used more. Hopefully this does as they are hoping and causes more people to start researching and developing in the touch direction.
Reply