1. Field of the Invention
The present invention is related to a handwriting apparatus, and more particularly related to an electromagnetic handwriting apparatus.
2. Description of the Prior Art
Most of the sensing theory of the handwriting apparatus (such as Tablet, Digitizer, Digital Whiteboard and so on) in market is Surface Acoustic Wave method, Electromagnetic method or Resistance method. Generally speaking, the Electromagnetic method is implemented by a double side sensing PCB board with X-axis and Y-axis antenna loops and an electromagnetic pen.
The electromagnetic pen using on the current electromagnetic handwriting apparatus can be divided into the handwriting apparatus with the battery electromagnetic pen and the handwriting apparatus with the battery-free electromagnetic pen. The battery electromagnetic pen is also called the active-type pen and this kind of the electromagnetic pen is not required the electromagnetic handwriting apparatus to transmit the electromagnetic energy to pen. The electromagnetic handwriting apparatus is only required to receive the electromagnetic signal from the electromagnetic pen. However, the drawback of the battery electromagnetic pen is the battery has to be replaced and the weight of the electromagnetic pen is a little heavy.
In addition, the battery-free electromagnetic pen is also called passive-type pen, such as the electromagnetic pen made by Wacom company and the detail specification is available in U.S. Pat. Nos. 4,878,553, 4,848,496 and 5,600,105. Because there is no battery inside the electromagnetic pen, the energy has to be transmitted from the handwriting apparatus to battery-free pen. Therefore, the antenna loop of the handwriting apparatus is required not only to receive the electromagnetic signal but also to transmit the electromagnetic energy to the its pen. When the handwriting apparatus is configured to detect the battery-free electromagnetic pen, the antenna loop is required to transmit the electromagnetic wave for couple time periods and then stop the electromagnetic wave transmitting and switch to the receiving mode. At the mean time, because the electromagnetic energy transmitted to the battery-free electromagnetic pen will soon dissipated quickly (the battery-free magnetic pen is not able to steadily transmit the electromagnetic power to the antenna loop), the antenna loop has to switch to the transmitting mode and the circuit is shown in
Moreover, there is another electromagnetic handwriting apparatus manufactured by Calcomp Company (U.S. Pat. No. 5,045,645) shown in
Therefore, according to the description above, it is necessary to design a new handwriting apparatus, which is able to overcome the drawbacks of the conventional handwriting apparatus and the electromagnetic pen is also configured without battery.
The object of the present invention is to provide a novel handwriting apparatus to continue transmitting the electromagnetic power to the battery free electromagnetic pen.
Another object of the present invention is to modify the complicated steps of the handwriting apparatus switching between energy-transmitting mode and signal-receiving mode.
According to the objects above, a handwriting input device with electromagnetic power transmitting is disclosed herein and includes a micro-controller, a power transferring coil, an electromagnetic pen, antenna loops and a filter. The micro-controller is configured to control for the first signal producing and the power transferring coil is configured to transfer the electromagnetic power of the first signal. The electromagnetic pen is configured to receive the electromagnetic power of the first signal and transform the electromagnetic power to be the second signal to transmit. The antenna loops are configured to receive the second signal and the filter is configured to filter the noise of the second signal.
According to the objects above, a handwriting input device with electromagnetic power transmitting is disclosed herein and includes a micro-controller, a power transferring coil, an electromagnetic pen, antenna loops, a filter, a sampling circuit and a counter. The micro-controller includes a first clock and a second clock and the first clock and an oscillator are configured to generate the first signal. The power transferring coil is configured to transfer the electromagnetic power of the first signal. The electromagnetic pen is configured to receive the electromagnetic power of the first signal and transform the electromagnetic power to be the second signal to transmit. The antenna loops are configured to receive the second signal and the filter is configured to filter the noise of the second signal. The sampling circuit is configured to sample the filtered second signal with sine wave and the counter and the clock are used to calculate the frequency of the second signal.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
The detailed description of the present invention will be discussed in the following embodiments, which are not intended to limit the scope of the present invention, but can be adapted for other applications. While drawings are illustrated in details, it is appreciated that the quantity of the disclosed components may be greater or less than that disclosed, except expressly restricting the amount of the components.
Subsequently, still referring to
It should be noted that the handwriting apparatus in the present invention further includes a sampling circuit 218, and the sampling circuit 218 is configured to sample the filtered second signal with sine wave and the second signal is then doing the analog/digital (A/D) signal convert by an A/D converter 2024 in the micro-controller 202. Moreover, a counter 220 and the second clock 2026 of the micro-controller 202 is used to calculate the frequency of the second signal with sine wave. Eventually, the micro-controller 202 will calculate the coordinate of the electromagnetic pen 216 in X-axis and Y-axis in accordance with the digital signal converted from the second signal and the frequency of the sine wave. In addition; the handwriting apparatus 20 in the present invention further includes a multiplexer 224 and the micro-controller 202 controls the multiplexer 222 to choose the signal from the drive circuit 214 or the antenna loop 206 to be the input signal and then transmit it to the filter 208.
As the description above, according to the circuit design of the handwriting apparatus 20 in the present invention, the handwriting apparatus 20 is able to continually transmit power to the electromagnetic pen 216 rather than the conventional handwriting apparatus is needed to switch the transmitting mode and the receiving mode. The electromagnetic pen 216 is also not required to install battery therein to keep transmitting the signal for the handwriting apparatus 20 to detect. On the other hand, in the circuit design, there is no Phase Comparator, Modulation (MOD) or Sync Demodulation (Sync Mod) installed therein to switch signal transmitting and signal receiving. In conclusion, the handwriting apparatus 20 in the present invention improves the drawback of the overweight of the conventional electromagnetic pen with battery and the problem of the half data rate of conventional battery-free pen without increasing the extra cost of the circuit design.
Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.
Number | Date | Country | Kind |
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099120117 | Jun 2010 | TW | national |