Patent Application
20150378453
This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 103121972 filed in Taiwan, R.O.C. on Jun. 25, 2014, the entire contents of which are hereby incorporated by reference.
The disclosure relates to an active capacitive stylus and a sensing method thereof, more particularly to an active capacitive stylus capable of sensing a pressing force by sensing the change of a resonant frequency output by an oscillation circuit, and to a sensing method thereof.
General capacitive stylus pens are usually disposed with a pen tip made of electric-conductive rubber or EMI gasket at the front end of its metal pen tube. Such a pen tip has a good wear resistance, a high response speed, achieves more accurate touch control than fingers and may be unable to scrape an external device. However, the external device has a lower sensibility in relation to the capacitive stylus pen so that it is difficult for the capacitive stylus pen to write small font-size words and even form desired writings on the external device based on the writing force.
Moreover, active capacitive styluses nowadays need a pressure sensor to sense a pressing force applied to the pen tip. For example, a capacitive pressure sensor as a pressure sensor converts a pressing force into an electrical signal by its capacitive sensing element. However, the disposition of pressure sensors will increase the manufacture costs and power consumption of an active capacitive stylus.
According to one or more embodiments, the disclosure provides an active capacitive stylus. In an embodiment, the active capacitive stylus includes a pen tip, a frequency adjuster, a frequency generating module, and a control module. When an external pressing force is applied to the pen tip, the pen tip simultaneously moves with the frequency adjuster. The frequency generating module, according to a location of the frequency adjuster, generates an induction signal having an induction frequency. After calculating a pressure value according to the induction signal, the control module encodes the pressure value into a digital control signal and sends the digital control signal to the pen tip.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, thus are not limitative of the present invention and wherein:
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawings.
Please refer to
The pen tip 10 is configured in the front part of the active capacitive stylus 1. The contact component 100 can receive a pressing force provided outside. For instance, the contact component 100 is a metallic conductor for transmitting signals such as a digital control signal. Also, the contact component 100 can receive signals from the control module 16 and then send them to a sensing region of another external device. In an example, the control module 16 sends a digital control signal to the contact component 100, and then the contact component 100 sends this digital control signal to a sensing region of an external device. For example, the external device is a tablet computer or any device with a touch panel. Therefore, the external device can perform a touch control function by the active capacitive stylus 1. In an embodiment, the control module 16 in the active capacitive stylus 1 can actively send out a positioning signal.
Please refer to
In an exemplary embodiment, when the contact component 100 touches a tablet computer, the contact component 100 is applied with a force, i.e. an external pressing force to move toward the inside of the active capacitive stylus 1 and simultaneously pushes the driving component 120 to move toward the inside of the active capacitive stylus 1. Moreover, because of the existence of the elastic component 122, the pushing force applied to the driving component 120 causes a restoring force that is opposite the pushing force. The elastic component 122 affects the relationship between the level of the external pressing force and the changing level of the location of the driving component 120. For example, the driving component 120 is, but not limited to, made of magnetic-conductive material or metal material. For example, the elastic component 122 is, but not limited to, a spring, a rubber spring or a rubber. The materials of the driving component 120 and the elastic component 122 can be selected according to actual application requirements.
The frequency generating module 14 at least includes a first inductor L1 and a first capacitor C1. The first inductor L1 has a first inductance, and the first capacitor C1 has a first capacitance. In an example, the first inductor L1 is a variable inductor (referred to as the variable inductor) having the first inductance that is adjustable while the first capacitor C1 is an invariable capacitor having the first capacitance that is not adjustable. In another example, the first inductor L1 is an invariable inductor having the first inductance that is not adjustable while the first capacitor C1 is a variable capacitor (referred to as the variable capacitor) having the first capacitance that is adjustable.
In an example, the driving component 120 in the frequency adjuster 12 is made of iron, zinc or other materials for adjusting the equivalent inductance when the first inductor L1 is a variable inductor. In an example, the driving component 120 is made of metal or other materials for adjusting the equivalent capacitance when the first capacitor C1 is a variable capacitor. Either the use of the variable inductor and invariable capacitor or the use of the invariable inductor and variable capacitor can be selected according to actual application requirements.
The driving component 120 has a distance with the variable inductor in an example or with the variable capacitor in another example. When the contact component 100 is not applied with any external pressing force, the contact component 100 and the driving component 120 do not move together. Herein, the distance between the driving component 120 and either the variable inductor in an example or the variable capacitor in another example is an initial induction distance. Therefore, the frequency generating module 14 has a resonant frequency as a basis resonant frequency under the principle of oscillation circuit. Data related to this basis resonant frequency is sent to the control module 16.
When the contact component 100 is applied with an external pressing force, the contact component 100 simultaneously moves with the driving component 120 and the location of the driving component 120 is changed. Herein, the distance between the driving component 120 and either the variable inductor in an example or the variable capacitor in another example is a pressed induction distance. Moreover, when the location of the driving component 120 is changed in response to the move of the contact component 100, the variable inductor senses a new second inductance in response to the move of the driving component 120 in an example or the variable capacitor senses a new second capacitance in response to the move of the driving component 120 in another example. Therefore, under the principle of oscillation circuit, the frequency generating module 14 has another resonant frequency referred to as a pressed resonant frequency. Data related to the pressed resonant frequency is sent to the control module 16.
Accordingly, the pressed induction distance and the pressed resonant frequency change in response to how much the external pressing force applied to the contact component 100 is. In an embodiment, the external pressing force and the pressed resonant frequency have a function relation therebetween. The relationship between the resonant frequency and the external pressing force is based on the elasticity and rigidity of the elastic component 122 and the move of the driving component 120. In an example, assume that the elastic component 122 has an elasticity index of 5 g/mm. When an external pressing force of 3 g is applied to the contact component 100, the elastic component 122 is moved by 0.6 mm. The capacitor coupling effect affects the equivalent capacitance of the variable capacitor in an example, and the inductor coupling effect affects the equivalent inductance of the variable inductor in another example. Moving the elastic component 122 by 0.6 mm causes that either the equivalent capacitance of the variable capacitor in an example or the equivalent inductance of the variable inductor in another example changes 12%, thereby changing the output frequency of the frequency generating module 14 (e.g. the oscillation circuit).
The inner components and their connections of the frequency generating module 14 are illustrated in details by referring to
Another embodiment of the frequency generating module is illustrated in
Please refer to
When the control module 16 encodes the pressure value by two different symbols “0” and “1” having different frequencies in the binary numeral system under a certain data format, the digital control signal is obtained. In an embodiment, for the digital control signal, the first bit corresponds to a first bit value, and the second bit corresponds to a second bit value. For example, the control module 16 encodes the pressure value by the binary numeral system to produce an 8-bit digital control signal such as 10100101. The person skilled in the art can choose a suitable calculation method and encoding method according to actual application requirements.
In another embodiment, the control module 16 encodes the pressure value and extra information, such as the status value of function key or information about the coordinate, the model number, the firmware version or the battery capacity, or any combination thereof, to produce the digital control signal. The status value of function key indicates the selection of a function key of the active capacitive stylus 1.
In another embodiment, the digital control signal includes a first frequency and a second frequency and is sent from the contact component 100 to an external device, such as a tablet computer including a transmission module to receiving the digital control signal. The contact component 100 herein is made of metal and capable of transmitting signal. Therefore, the external device can fulfill the result of sensing the pressing force. In an example, assume that the digital control signal is an 8-bit binary signal of 10100101. “0” of the 8-bit binary signal indicates a first frequency, and “1” of the 8-bit binary signal indicates a second frequency. The front 4-bit stream “1010” of the 8-bit binary signal indicates the level of the pressing force applied to the contact component 100, and the last 4-bit stream “0101” of the 8-bit binary signal indicates a function corresponding to a function key. Therefore, the external device can use information indicated in the digital control signal. The person skilled in the art can define the data status specified by a bit value according to actual application requirements.
Please refer to
Similar to the active capacitive stylus 1 in
However, the differences between the active capacitive stylus 1 in
The boost converter 32 is coupled to the power device 30 and the control module 26, and the light source device 34 is coupled to the control module 26. The power device 30 supplies power to the active capacitive stylus 2 and is, for example but not limited to, a battery. The boost converter 32 converts the power provided by the power device 30 into the electricity for the control module 26. The light source device 34 receives signals from the control module 26 and controls the operation of the light source device 34. In an example, if the electricity provided by the power device 30 or the electricity amplified by the boost converter 32 is lower than the need of the control module 26, the control module 26 will send a signal to control the lighting of the light source device 34 for notifying users that the active capacitive stylus 2 is running out of power.
Please refer to
In an embodiment, the control module 46 merely encodes the pressure value to produce the digital control signal. In another embodiment, the control module 46 encodes the pressure value and one or more extra information, such as information about the coordinate, the selection of function keys, the model number, the firmware version, or the battery capacity related to the active capacitive stylus 4, to produce the digital control signal such that the external device can use such extra information after receiving the digital control signal. In another embodiment, the control module 46 encodes the pressure value and one or more extra information, such as the information about the selection of function keys, the model number, the firmware version, or the battery capacity related to the active capacitive stylus 4, to produce the digital control signal and encodes the coordinate information to produce a positioning signal with a certain frequency. Then, the control module 46 sends the digital control signal to an external device through the wireless transceiving module 48 and outputs the positioning signal to an amplifier. After amplifying the positioning signal, the amplified positioning signal is sent to the contact component 400 and then is transferred to a sensing region of the external device from the contact component 400 so that the external device can verify the location of the active capacitive stylus 4.
In an example, the wireless transceiving module 48 is, but not limited to, a Bluetooth device, Wi-Fi device, or other devices for wireless signal transmission. In an example, the active capacitive stylus 4 can communicate with an external device in opposite directions by the bidirectional digital transmission technology and the operation of the wireless transceiving module 48 so that users can do operations such as function setting or firmware updating to the active capacitive stylus 4.
In view of the various foregoing embodiments of the active capacitive stylus, a sensing method of the active capacitive stylus is concisely summarized and illustrated as follows by referring
In summary, the active capacitive stylus in the disclosure employs the above frequency generating module (e.g. an oscillation circuit) including a variable inductor or capacitor to provide an equivalent inductance or capacitance in response to the move of the driving component in the above frequency adjuster, thereby changing an induction frequency of the above frequency generating module. Also, the above control module is employed to calculate a pressure value according to the induction frequency, encode at least the pressure value into a digital control signal, and send the digital control signal to an external device including a touch panel. Since the active capacitive stylus in the disclosure operates without any pressure transducer or force sensor, the active capacitive stylus may sense a pressing force under lower power consumption and manufacture costs.
| Number | Date | Country | Kind |
|---|---|---|---|
| 103121972 | Jun 2014 | TW | national |
