The present invention relates to a rechargeable electromagnetic pen, and more particularly to a rechargeable electromagnetic pen with electrical power source.
A product set of digital tablet often includes an electromagnetic pen and a digital tablet. A digital tablet usually comprises inductive antenna loops and a printed circuit board including an analog/digital converter, an amplifier and processor/control IC, which is used to sense and process electromagnetic signals transmitted from the electromagnetic pen. The electromagnetic pen comprises a LC circuit including an inductor and a capacitor and varies transmitting frequency and inductance according to tip pressure of the electromagnetic pen pressing on the digital tablet. The tip pressure of the electromagnetic pen pressing on the digital tablet is shown on a display device by the line width of the trace of the electromagnetic pen. When the electromagnetic pen touches and moves on the digital tablet, the electromagnetic signals transmitted are received by the inductive antenna loops of the digital tablet and are processed to input data comprising locations, traces and frequency variations to a host such as a computer. The data are calculated through software to display on the display device.
Electromagnetic pens include battery-powered type and battery-less type. The battery-powered electromagnetic pen uses at least one dry battery or other replaceable power sources as the power source. However, using battery or other replaceable power sources as power source has several drawbacks such as increased weight, increased loading of user, limited battery life and inconvenience of battery replacement.
In order to solve the above-mentioned problems, the invention provides a rechargeable electromagnetic pen with electrical power source to provide advantages including reducing the loading of user, decreasing the weight of the electromagnetic pen, avoiding the inconvenience of battery replacement, and increasing the convenience of using electromagnetic pen.
An object of the present invention is to provide a rechargeable electromagnetic pen with electrical power source to decrease the weight of the electromagnetic pen, to upgrade the efficiency of charging and to increase endurance of power source and the convenience of using electromagnetic pen.
According to the object, one embodiment of the present invention provides a rechargeable electromagnetic pen. The rechargeable electromagnetic pen comprises an electrical power source system, a power receiving terminal and a signal transformation circuit. The electrical power source system provides the rechargeable electromagnetic pen with electrical power for emitting electromagnetic signal to a receiving terminal. The power receiving terminal receives electrical power signals generating from non-contact electromagnetic induction. The signal transformation circuit processes and transforms the electrical power signals and charging the electrical power source system.
The invention also provides an input device using a rechargeable electromagnetic pen. The input device comprises a digital tablet comprising antenna loops and a rechargeable electromagnetic pen. The rechargeable electromagnetic pen comprises an electrical power source system, a power receiving terminal and a signal transformation circuit. The electrical power source system provides the rechargeable electromagnetic pen with electrical power for emitting electromagnetic signal to a receiving terminal. The power receiving terminal receives electrical power signals generating from non-contact electromagnetic induction. The signal transformation circuit processes and transforms the electrical power signals and charging the electrical power source system.
The accompanying drawings illustrate various embodiments of the present invention and are a part of the specification. The illustrated embodiments are merely examples of the present invention and do not limit the scope of the invention.
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 scale of each component may not be expressly exactly.
The electrical power source system 202 stores electrical power energy from the charge site 208 and the power receiving terminal 206, and provides the oscillation circuit 210 with electrical power. The electrical power source system 202 comprises, but not limited to, at least one electric double-layer capacitor. The electric double-layer capacitor is also as known as supercapacitor, or ultracapacitor, or electrochemical double layer capacitor, or gold capacitor. The electric double-layer capacitor has advantages including small size, large capacitance, high specific capacitance and high power density of energy storage. The operation temperature of the electric double-layer capacitor is within the range of about −40° C. to 85° C. comparing to the operation temperature range of 0 to 40° C. of secondary battery or the operation temperature range of −20° C. to 60° C. of common battery. The electric double-layer capacitor has excellent performance of charging and discharging and much higher power density than that of Li-ion battery so that the electric double-layer capacitor is suitable for large current discharging. One 4.7 Farad electric double-layer capacitor can discharge 18A current in a very short time. The electric double-layer capacitor also has advantages of short charging and discharging time, simple charging circuitry. The electric double-layer capacitor does not need constant current charging and charging/discharging control circuit and does not have memory effect. Conventional secondary battery has limitation of charging/discharging current and needs long charging time from several hours to dozens hours while the electric double-layer capacitor does not has limitation of charging/discharging current. The electric double-layer capacitor can be charged quickly in few seconds to dozens seconds. The electric double-layer capacitor has characteristic of stable voltage and small leak current. The electric double-layer capacitor has long life time and can be charged and discharged over half million times 500 times larger than that of Li-ion battery, 1000 times larger than Ni—MH and Ni—Cd batteries. The electric double-layer capacitor can be used for 68 years long if it is charged and discharged 20 times a day. Moreover, the materials of the electric double-layer capacitor are easy to obtained and the production cost is low. Furthermore, the electric double-layer capacitor does not need maintenance and can be completely encapsulated.
The invention provides a rechargeable electromagnetic pen with electrical power source to store power through a power transmission module or a charge site without using any secondary battery or conventional dry battery so that the weight of the electromagnetic pen can be reduced. In one embodiment, an electric double-layer capacitor is used as the power source to increase the convenience, the charging efficiency and the lifetime of electromagnetic pen. The electric double-layer capacitor can be discharged in large current and the danger of discharging is greatly reduced.
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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098112828 | Apr 2009 | TW | national |