Touch Screen

Touch Screen allows users to just use your fingers gently touch the computer screen or text on the icons on the host OS can be achieved, so get rid of the keyboard and mouse, make computer interaction more straightforward. Hall is mainly used in public places, information inquiry, leadership office, video games, song a la carte, multimedia, tickets / ticket pre-sale and so on. Products are mainly divided into capacitive touch screen, resistive touch screen and three types of surface acoustic wave touch screen.Touch-screen display categoriesDepending on the touch screen and works with the media, can be divided into resistive, capacitive, infrared-and surface acoustic wave, optical and other.Edit this paragraph touchscreen display technologyTouch-screen display technology is a new interactive input mode, with the traditional keyboard and mouse input as compared to touch screen input is moreAnd intuitive. Beijing Heng Yuan Technology Development Co., Ltd. Techtronic market to meet customer needs, has developed a multi-touch screen display, with the recognition software, touch screen handwriting input can be achieved. Touch screen monitor installed in the front of the screen and touch screen controller detection component parts. When fingers or other objects touch display installed in front of the touch screen, the touch position detected by the touch screen controller, and through the interface (such as RS-232 serial port) to the host.Large touch screen functionMultifunctional smart board and computers, projectors together to form a large touch screen, the computer screen through the projector projected onto the smart board to replace the mouse pointer or finger operation in the smart-board computer, control and application software, Windows or Macintosh.Surface acoustic wave touch screenSurface acoustic wave touch screen touch screen part of the glass is a transparent, it can be made flat, cylindrical or spherical, and the surface of the touch screen does not need to add a special coating. This kind of touch screen on the corner with the ultrasonic transducer can transmit a high frequency sound waves across the screen surface. When a finger or other be able to absorb or block sound energy of an object touching the screen, parts of the acoustic energy through the fingers are partially absorbed, according to the coordinates of the receiver can determine the location of the signal changes. The same compared to other types of touch screen, surface acoustic wave touch screen independent of temperature, humidity and other environmental factors, high resolution; transmittance is good, can maintain a clear bright image quality; reaction speed; a third axis (ie pressure axis ) response, so widely.

Touch Screen

For operational convenience, people use the touch screen to replace the mouse or keyboard work, we must first use your fingers or other objects touch installed in front of the monitor touch screen, then the system according to the finger touching the icon or menu location to locate selected information into the touch screen by the touch detection component parts and touch screen controller; touch detection unit installed in the front of the monitor screen for detecting user touch position, touch screen controller to accept evacuation; and touch screen controller's main role is from the touch point touch detection device to receive information, and transform it into contact coordinates, and then sent to CPU, it also can receive commands sent to the CPU and run it.Functional classificationInfrared touch screenInfrared touch screen, very simple principle, but on the display rack with light pitch box, the screen surface with no coating or optical connection controller pitch frames, arranged in four sides of the infrared emission tube and receiver tube, the surface of the screen the formation of an infrared network users to a certain point a finger touch screen, it will block if they had been the location of two infrared touch computer can immediately calculate the position from current and voltage infrared touch screen and electrostatic interference, some of the harsh environmental conditions suitable for its The main advantage is low cost easy to install no card or any other controller can be used in all grades on the computer, however, because only an increase in the general framework of the screen, in the course of infrared frames, around the launch tube and receiver tube is easily damaged, and the lower resolutionCapacitive touch screenCapacitive touch screen of the structure mainly in the glass screen coated with a transparent film layer, the longer the conductor layer, plus a protective glass, double glass design can completely protect the conductor layer and the sensor capacitive touch screen on the touch screen edges are coated with narrow electrode, the conductive body to form a low voltage AC field when the user touches the screen, because the body electric, fingers and the conductor layer to form a coupling capacitor, four sides of the electrode current will flow to the contact issue, but the current strength of the finger to proportional to the distance between electrodes in the touch screen controller will calculate the current ratio and strength, accurately calculate the location of the touch points of the dual-glass capacitive touch screen can not only protect the conductors and sensors, to more effectively prevent external environmental factors on Touch-screen impact, even if the screen of dust or grease stained with dirt, capacitive touch screen is still able to accurately calculate the location of the touchResistive touch screenTouch screen panel is a body part with the display surface of the well in line with the multi-layer composite film by a layer of glass or plexiglass as a grass-roots, the surface coated with a layer of transparent conductive layer (OTI, indium oxide), and then covered with a layer above the outer surface smooth and scratch-resistant hardened plastic layer, and its inner surface is also coated with a layer of OTI, the two conductive layers there are many small (less than one thousandth inch) separation point of transparency when they are separated by a finger contact with insulation screen, two conductive layers OTI A point of contact, because one side of the conductive layer connected to the Y-axis voltage of 5V uniform field, making the detection level of the voltage from zero to zero, after the controller detects the connected , the A / D conversion, and will be compared to the voltage to 5V, you can get the touch point Y axis X axis coordinates obtained empathy, which is a common resistive touch screen technology screen according to the most basic principles of resistance Lead-out of how many, is divided into four-five-wire resistive touch screen and other multi-line five-wire resistive touch screen A-conductive glass surface is not conductive coating, conductive glass technology to greatly increase the life span, and can improve transmittance OTI resistive touch screen coating is thin and easy to brittle fracture, the thick coating will reduce the formation of internal reflection to reduce light transmission and clarity, OTI, although more a thin outer protective layer of plastic, but still easily damaged by sharp objects; and because often touched the surface after a certain time to use OTI hairline cracks will appear, and even variants, such as the outer one of which damaged and broken OTI, will lose the role as a conductor, not the life of the touch screen Resistive touch screen long but water contamination from dust impactSurface acoustic wave touch screenSurface acoustic wave touch screen touch screen can be a part of spherical or cylindrical surface of the glass plate, mounted on CRTLEDLCD or plasma display screen in front of the glass plate is a piece of pure glass, apart from other touch-screen technology is no film and cover the upper left and lower right corner of the glass screen of the fixed vertical and horizontal direction of the ultrasonic transmitter transducer, the upper right corner is fixed two corresponding ultrasonic receiver transducer around the glass screen is engraved with four 45 ° angle intervals from sparse to dense reflective stripes very sophisticated transmitter transducer to the controller via the touch screen cable into electrical signals sent to the left side surface of the acoustic energy to pass, and then by a group of precision glass below the reflective stripes the acoustic energy reflected into a uniform surface upward transmission of acoustic energy through the screen surface, and then gather by the reflective stripes on top of the line spread to the right into the X-axis receiving transducer, receiving transducer will return to the surface of the acoustic energy into electrical signals and transmit the received signal waveform in the absence of touch when the received signal waveform and the reference waveform the same as when a finger or other acoustic energy to absorb or block the object touching the screen, X-axis position to go up through your fingers The acoustic energy is partly absorbed, reflected in the received waveform on the waveform location that is a time gap there is a received waveform corresponding to the decay part of a finger to block the signal attenuation of a gap, the gap calculated coordinates of the location that was touched, the controller analyzes the received signal attenuation determined by the location of the gap after the X-coordinate Y axis the same process to determine the Y coordinate of the touch points in addition to general touch screen can respond to the XY coordinates, the surface acoustic wave touch panel also responded to the third axis Z-axis coordinates, the user is able to perceive the size of the value of three-axis touch-pressure, once established, they put the controller to the host surface acoustic wave touch screen from temperature, humidity and other environmental factors, high resolution, has an excellent scratch resistance, long life (50 million times without failure ); high transmittance (92%), to maintain a clear bright image quality; no drift, the most suitable for use in public places but the surface of the sensor system in the long induction converter operation, the acoustic energy generated due to the pressure damage generally wool or leather gloves will receive part of the sound waves, the accuracy of the sensor is also affected by some surface or screen finger touch screen, such as dirt or dust contaminated with grease stains, will also affect its performance, even so the system stops operation.

Touch Screen

The touch screen is introduced

Also called a touch screen, only one control skills, divided into two ( capacitance, resistance screen ).

Touch screen based on the medium as well as the working principle, can be divided into resistive, capacitive induction, infrared type and surface acoustic wave type four. Touch screen from low-grade to high-grade gradually upgrade and development: from the resistance type, infrared type to capacitor induction type and surface acoustic wave.

Multi touch technology

Touch technology we are not unfamiliar, already had. Bank teller machine is mostly a touch screen, a lot of hospital, library, hall has the touch technology computer. Support touch screen mobile phone, MP3, digital cameras are also many. Touch technology, with fingers instead of the keyboard and mouse, which display in addition to the maximum of humanity, and in certain situations reducing the mouse and keyboard. But these already existing touch screen is a single touch, also can saying is resistive touch. His main drawback is the only recognition and support each time a finger touch, click.

This year, Microsoft in talking about multi-touch applications, the upcoming release of the Windows 7 ( Vista upgrade product) will fully support multi-touch technology. Multi touch technology is a touch technology revolution, that is the screen will be able to identify your five finger while doing the click, the touch-control action. We know that a finger can only do the action of a click, but five fingers derived action will be a lot of very rich. Unfortunately there is no see this multitouch computers, HP is said to do a can support two finger movements of the touch screen.

Why is iPhone so hot, the key is its multi-touch screen technology, the other mobile phone manufacturer is deadly. The company has for the multi touch technology applied for two patents.

Multi touch technology and is not easy to achieve, it is from hardware to software of an organic whole, can saying is a system engineering.

Capacitive touch screen

Capacitor type touch screen using the human body sensing of the current work. Capacitive touch screen is a piece of four layer composite glass screen, glass screen and the inner surface of the interlayer is coated with a layer of ITO ( conductive glass coating ), the outer layer is a thin layer of silica glass protection layer ITO coating is used as a working surface, a four angle from four electrodes, inner ITO is a shielding layer in guarantee a good working environment. When a finger touches the metal layer, the body electric, the user and the touch screen surface to form a coupling capacitor for high frequency current, capacitance is direct conductor, then from the point of contact fingers from a very small current. The current from the touch screen on the four corners of the electrode outflow, and flows through the four electrode current and the finger to the four angle is proportional to the distance, the controller based on the four current ratio calculation, the touch point position information.

Capacitor type touch-control screen advantages

And resistance type touch screen and electromagnetic induction board compared to a capacitive touch screen showed better performance. Because touch feel, easy to use. And the fingers and touch screen contact with almost no wear, stable performance, via mechanical testing the service life of 30 years. In addition, the product is mainly composed of a only a high-integration chip PCB structure, less components, good product consistency, high rate of finished products.

Capacitive touch screen.

On behalf of the popular leader iPhone using a capacitive touch screen will undoubtedly further prove its have various advantages. However, xiabuyanyu, capacitive touch screen is also facing the following challenge: because the body become a circuit part, so the drift phenomenon more serious ; capacitive sensing input technology in small and medium size flat panel display input or control point target (such as a soft keyboard on the phone number or the input word ) when the application needs to be improvement; temperature and humidity drastic changes performance not stable enough to be calibrated frequently ; not applicable to metal cabinet ; when the external inductance and magnetic induction time, may make the touch screen to malfunction. Although available pen tool instead of a finger touch, but its price is more expensive.

Resistance type touch screen

Resistive touch screen ( Touch panel of resistance) also known as resistive touch panel, is a can receiving contact input signal induction type liquid crystal display device, when contact is made with the graphics on the screen button, the screen of a tactile feedback system can be based on pre-programmed program drive link device, can be used to replace a mechanical type the button panel, and by the liquid crystal display screen manufacturing vivid video and audio effect.

As they are a kind of completely isolated from the outside world working environment, no dust, water and oil

It can use any object to touch, can be used for writing and drawing, this is their comparative advantage

The resistive touch screen accuracy depends only on the A / D conversion accuracy, it can easily achieve 4096 * 4096, compared to five line resistance than four wires to ensure resolution accuracy but also is superior, but the cost is large, so the price is very high.

1, four wire resistive touchscreen

Four wire resistance analog technology of two layers of transparent metallic layer each layer were increased when 5V constant voltage : a vertical direction and a horizontal direction. A total of four cables. Features: high resolution, high speed transmission response. The hardness of the surface treatment, reduce abrasion, scratch and chemical processing. With the glossy and matte deal. A correction, high stability, and never drift.

2, five wire resistive touchscreen

Five wires resistive touch screen technology base to two directions of the voltage field via a precision resistor network are added in the glass conductive surface, we can be simply understood as two orientations of the voltage field work time and in the same plane, while the outer layer of nickel metal conductive layer only used as pure conductor there is touch, time-sharing detecting inner ITO contact points X and Y axis voltage value is measured by means of the position of the touch point. Five wire resistive touch screen inner ITO four lead wires, outer conductor just only a touch screen to lead a total of 5. Features: high resolution, high speed transmission response. High surface hardness, reduce abrasion, scratch and chemical processing. With the point of contact of 30000000 can be used. Conductive glass substrate of the medium. A correction, high stability, and never drift. Five wire resistive touch screen with high price and high demand for environment.

3, resistive screen limitations

Whether four or five wire resistive touch screen wire resistive touch screen, which is a kind of completely isolated from the outside world working environment, not afraid of dust and water vapor, it can use any object to touch, and can be used to write and paint, more suitable for the field of industrial control and office limited use. Resistive touch screen common shortcoming because composite film outer layer is made of plastic materials, people who do not know too much force or use sharps touch may scratch the touch screen and scrapped as a result. However, at the limit, scratches will only hurt the outer conductive layer, the outer conductive layer scratch for five wire resistive touch screen, it doesn't matter, and on four wires resistive touch screen is fatal.