電容性觸控面板上的觸控筆（續前文）

看到Apple自己申請的觸控筆專利
發現在它之前有不少類似需要電力的電容性面板觸控筆專利，而且有些也己經在市面上看到，包括HTC flyer的觸控筆、HP tablet pc的觸控筆（可以變成滑鼠模式）

類似專利是頗多，各有巧妙不同，但是初送件的範圍皆廣，相關結構也都是簡單且具有類似的電氣特性：

US 2010/0053113

1. An electromagnetic stylus for controlling a capacitive touch panel comprising:
a housing;
a signal transducer for accessing a frequency signal of the capacitive touch panel;
a transceiving winding encircling the signal transducer for receiving and transmitting wireless signals having a frequency similar to a frequency of the capacitive touch panel;
a synchronizing winding encircling the signal transducer for generating a frequency signal having a frequency similar to the frequency of the capacitive touch panel through oscillation;
an oscillator for amplifying the frequency signal generated by the synchronizing winding; and
a circuit board installed inside the housing and connected to the signal transducer for processing the frequency signal amplified by the oscillator.

US 2010/0053120

1. A touchscreen stylus applying to a capacitive touchscreen and comprising:
a body being hollow, having an accommodating space thereinside, and having an electric-conduction element at one end thereof, wherein said electric-conduction element is used to contact said capacitive touchscreen; and
a coil arranged inside said accommodating space, electrically coupled to said electric-conduction element, receiving current from said touchscreen via said electric-conduction element to form a current loop and generate an induced electric field.

US 2010/0170726

1. An apparatus for touch input, comprising:
a capacitive touchpad module; and
an electronic stylus for emitting an excitation signal to apply to a trace of the capacitive touchpad module near a touch point when the electronic stylus touches the capacitive touchpad module, so as to change a waveform of a charging/discharging signal in the trace.

US 2009/0256824

1. A pointer device for being used with a capacitance sensitive touch screen having a touch sensitive surface, the pointer device comprising:
a conductive pointer tip; and
a passive conductive element,
wherein said conductive pointer tip is electrically connected to said passive conductive element for providing a capacitive disturbance on said touch sensitive surface when said pointer device touches said surface.

Ron