Infrared multi-touch screen principle analysis
The working principle of the external touch screen is that the infrared receiving tube and the infrared emitting tube are arranged around the touch screen, and the infrared tubes are arranged in a corresponding position relationship on the surface of the touch screen to form an optical network formed by infrared rays, when there is an object. (Can be a finger, a gloved hand or any touch object) When entering the infrared light net to block somewhere in the infrared emission reception, the intensity of the infrared light received by the receiving infrared tube in both the horizontal and vertical directions changes. The device knows where to touch by knowing the changes in the reception of infrared light. Through the design of the hardware and the programming of the software, the infrared touch screen can interpolate the data of each point and achieve the resolution of 4096×4096. Due to the working principle of the infrared touch screen itself, it can be used without pressure (refer to the touch). The touch of the body exerts pressure on the touch screen itself, so that no glass work can be achieved. In the same instant when the infrared touch screen is working, only a pair of infrared pair tubes (referring to a launch tube and a receiving tube corresponding to the physical position) are working on the data, and the circuit passes the high frequency data collection of the infrared pair tube. Reach a quick response.
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Infrared multi-touch screen principle analysis is a kind of touch product compared with single-point infrared screen and virtual two-point infrared screen. It is a technological innovation of infrared touch screen. Its principle mainly relies on the software algorithm in firmware to solve more than two points simultaneously. The touch operation does not interfere with the problem. The difference between the true two points and the virtual two points is manifested in high stability and fast response, and there is no misoperation such as jumping points and running points.
The obvious advantage of infrared touch screen and capacitive resistive screen is that it is not subject to current, voltage and static interference, and is suitable for harsh environmental conditions. Infrared technology is the mainstream development trend of touch screen products. Touch screens using acoustics and other materials science techniques have insurmountable barriers, such as damage and aging of a single sensor, and the touch interface is subject to contamination, destructive use, and maintenance.
There are three technical difficulties in infrared detection technology for touch screen technology:
1. Ambient light factor, the infrared receiving tube has the working range between minimum sensitivity and maximum illuminance, but the touch screen product can not limit the scope of use, from the dark karaoke private room to the outdoor use under the high intensity sunlight of Hainan Island, as a product, It must be adapted, and the infrared screen manufacturers that are currently able to resist direct sunlight on the market have gradually emerged.
2, response speed, since 2008, infrared technology has developed rapidly, and has achieved response speed below 15ms.
3. Signal diffraction, ambient reflection, refraction, interference, the infrared emission tube has an emission angle, and the receiving tube has a large receiving angle. If the surrounding reflection is to a certain extent, the finger can not block the signal at any place. Proper adjustment of power can achieve precise touch.
In order to better solve the above problems, the biggest advantage of choosing the analog mode is that it can analyze and improve the resolution of the touch screen, but the anti-interference ability can't compare with the pulse mode; although the pulse selection mode has strong anti-interference ability, there is a pulse mode required by the receiver. A problem that responds to the process time, while the touch screen requires extremely fast speed, so there must be technical breakthroughs in adaptive circuits, microcontroller software, mold design, and choice of light-transmissive materials.
Main feature
1. Supports six precise touch points (detectable up to ten touch points)
2. Single USB power supply: power and communication share USB data cable
3. Ultra low power consumption: work ≤ 750mW; standby ≤ 250mW
4. Low cost and high cost performance
5. No card or any other controller required
6. Positioning accuracy: extremely stable and reliable performance
7. No ghosts
8. High light transmission, achieving 95%-100% true light transmittance
9. Unlimited number of touches
10. Good stability, no drift, no drift with time and environment
11. Sensitive operation, full mouse function through finger or any other physical touch
12. Suitable for vertical and horizontal display installation
13. Can be touched by any object, such as: wearing gloves, touching pen, finger
14. Four-point precise positioning
15. Suitable for any display size
16. Full support for the TUIO protocol
17. Applicable to Windows 7, Vista, XP, MacOS*, Linux* operating system
18. Adaptable, free from current, voltage, static electricity, can adapt to various environments
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