Infrared Touch Screen is the first option for big size touch screen
however
in actual application
there are some general deficiencies like insufficient resolution
low response speed and complicated fabrication and assembling process in mass production. To improve these defects
a design scheme of infrared screen is proposed. In hardware section
the two-dimension strobe infrared scanning circuit
receiving circuit and filtering circuit are incorporated to modularize the transmitting and receiving circuits and facilitate the fabrication and assembling process. In software section
a pulse infrared scanning method is proposed first and the approaches to the pulse scanning based on Timer and ADC built in STM32F205 is also defined
by which the scanning speed of infrared screen is improved. Then the design idea of rescanning is introduced to improve the positioning accuracy of touching point on infrared screen by rescanning without cost increase in hardware.At last
the approaches to HID report descriptor which supports multiple points touching is described to realize the driver-free installation of infrared screen. The actual application proves that the design lessens the fabrication complexity and fulfill the plug-and-play function and effectively improved the definition and response speed of infrared touch screen.
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references
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