By Lojoman


TV online


Tuesday, July 31, 2007

Large touch screen monitor

Link to information

NextWindow 2400 Touch Screen Overlay
NextWindow's 2400 touch overlay attaches to any manufacturer's LCD or plasma display from 23" to 65". Within a few minutes, you can convert a standard display to an interactive touch screen with full mouse functionality. Combine this with exciting interactive software, and you can create a high-impact, interactive display for many purposes - ideal for digital signage, advertising, wayfinding, and education in conference or class rooms.
The 2400 series provides a straightforward easy-to-install solution that offers all the benefits of NextWindow's optical touchscreen technology:
Clear glass for maximum image clarity.
Light touch—no pressure required.
Any touch method can be used—finger, gloved hand or pointer.
Once-only, four-point calibration. No drift.
Serial interface or plug-and-play USB connection.
Landscape or portrait orientation.
Note: the 2400 Touch Overlay is not suitable for displays mounted on desk-top stands...
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Monday, July 30, 2007

LCD touch screen

Touchscreens, touch screens, touch panels or touchscreen panels are display overlays which have the ability to display and receive information on the same screen. The effect of such overlays allows a display to be used as an input device, removing the keyboard and/or the mouse as the primary input device for interacting with the display's content. Such displays can be attached to computers or, as terminals, to networks. Touchscreens also have assisted in recent changes in the PDA and Cell-Phone Industries, making these devices more usable.
There are a number of types of touch screen technology:
A resistive touch screen panel is coated with a thin metallic electrically conductive and resistive layer that causes a change in the electrical current which is registered as a touch event and sent to the controller for processing.
Some resistive panels can estimate the area (and hence the pressure) of a touch based on calculations from the resistances.
Resistive touch screen panels are generally more affordable but offer only 75% clarity[citation needed] (premium films and glass finishes allow transmissivity to approach 85%[citation needed]) and the layer can be damaged by sharp objects. Resistive touch screen panels are not affected by outside elements such as dust or water and are the type most commonly used today.
Surface Acoustic Wave (SAW)
Surface Acoustic Wave technology uses ultrasonic waves that pass over the touch screen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Surface wave touch screen panels can be damaged by outside elements. Contaminants on the surface can also interfere with the functionality of the touchscreen.
A capacitive touch screen panel is coated with a material, typically indium tin oxide that conducts a continuous electrical current across the sensor. The sensor therefore exhibits a precisely controlled field of stored electrons in both the horizontal and vertical axes - it achieves capacitance. The human body is also an electrical device which has stored electrons and therefore also exhibits capacitance. When the sensor's 'normal' capacitance field (its reference state) is altered by another capacitance field, i.e., someone's finger, electronic circuits located at each corner of the panel measure the resultant 'distortion' in the sine wave characteristics of the reference field and send the information about the event to the controller for mathematical processing. Capacitive sensors can either be touched with a bare finger or with a conductive device being held by a bare hand. Capacitive touch screens are not affected by outside elements and have high clarity, but their complex signal processing electronics increase their cost.
An infrared touch screen panel employs one of two very different methodologies. One method used thermal induced changes of the surface resistance. This method was sometimes slow and required warm hands. Another method is an array of vertical and horizontal IR sensors that detected the interruption of a modulated light beam near the surface of the screen. IR touch screens have the most durable surfaces and are used in many military applications that require a touch panel display.
Strain Gauge
In a strain gauge configuration the screen is spring mounted on the four corners and strain gauges are used to determine deflection when the screen is touched. This technology can also measure the Z-axis. Typical application include protecting new touch-screen railway ticket machines from vandalism.
Optical Imaging
A relatively-modern development in touch screen technology, two or more image sensors are placed around the edges (usually the corners) of the screen. Infrared backlights are placed in the camera's field of view on the other sides of the screen. A touch shows up as a shadow and each pair of cameras can then be triangulated to locate the touch. This technology is growing in popularity, due to its scalability, versatility, and affordability, especially for larger units.
Dispersive Signal Technology
Introduced in 2002, this system uses sensors to detect the mechanical energy in the glass that occur due to a touch. Complex algorithms then interpret this information and provide the actual location of the touch. The technology claims to be unaffected by dust and other outside elements, including scratches. Since there is no need for additional elements on screen, it also claims to provide excellent optical clarity. Also, since mechanical vibrations are used to detect a touch event, any object can be used to generate these events, including fingers and styli.
Acoustic Pulse Recognition
This system uses more than two piezoelectric transducers located at some positions of the screen to turn the mechanical energy of a touch (vibration) into an electronic signal. This signal is then converted into an audio file, and then compared to preexisting audio profile for every position on the screen. This system works without a grid of wires running through the screen, the touch screen itself is actually pure glass, giving it the optics and durability of the glass out of which it is made. It works with scratches and dust on the screen, and accuracy is very good. It does not need a conductive object to activate it. It is a major advantage for larger displays.
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Tuesday, July 10, 2007

Monitor Brand (for PC)

Monitor Brand (for CAR PC)


TFT-LCD (Thin Film Transistor-Liquid Crystal Display) is a variant of Liquid Crystal Display (LCD) which uses Thin-Film Transistor (TFT) technology to improve image quality. TFT LCD is one type of active matrix LCD, though it is usually synonymous with LCD. It is used in televisions, flat panel displays and projectors.

Normal Liquid Crystal Displays like those found in calculators have direct driven image elements – a voltage can be applied across one segment without interfering with other segments of the display. This is impractical for a large display with a large number of picture elements (pixels), since it would require millions of connections - top and bottom connections for each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels are addressed in rows and columns which reduce the connection count from millions to thousands. If all the pixels in one row are driven with a positive voltage and all the pixels in one column are driven with a negative voltage, then the pixel at the intersection has the largest applied voltage and is switched. The problem with this solution is that all the pixels in the same column see a fraction of the applied voltage as do all the pixels in the same row, so although they are not switched completely, they do tend to darken. The solution to the problem is to supply each pixel with its own transistor switch which allows each pixel to be individually controlled. The low leakage current of the transistor also means that the voltage applied to the pixel does not leak away between refreshes to the display image. Each pixel is a small capacitor with a transparent ITO layer at the front, a transparent layer at the back, and a layer of insulating liquid crystal between.
The circuit layout of a TFT-LCD is very similar to the one used in a DRAM memory. However, rather than building the transistors out of silicon which has been formed into a crystalline wafer, they are fabricated from a thin film of silicon deposited on a glass panel. Transistors take up only a small fraction of the area of each pixel, and the silicon film is etched away in the remaining areas, allowing light to pass through.
The silicon layer for TFT-LCDs is typically deposited using the PECVD process from a silane gas precursor to produce an amorphous silicon film. Polycrystalline silicon is also used in some displays where higher performance is needed from the TFTs, typically in very high resolution displays or ones where performing some data processing on the display itself is desirable. Both amorphous and polycrystalline silicon TFTs have very poor performance compared with transistors fabricated from single-crystal silicon.