WO2009031758A1

WO2009031758A1 - Input pen and the input system using the same

Info

Publication number: WO2009031758A1
Application number: PCT/KR2008/004455
Authority: WO
Inventors: Do Young Ko; Jae Jun Lee
Original assignee: PNF Co Ltd
Current assignee: PNF Co Ltd
Priority date: 2007-09-05
Filing date: 2008-07-31
Publication date: 2009-03-12
Anticipated expiration: 2010-03-05
Also published as: KR100890366B1; KR20090025097A

Abstract

Disclosed are an input pen and an input system using the same. More natural handwriting data can be input by measuring pressure applied to a pen nib of the input pen, and inputting as handwriting data the pressure together with location. In addition, it is examined whether or not pressure is applied to the input pen. Only when pressure is applied to the input pen, it is determined that a user inputs handwriting, and the pressure applied to the input pen is measured. It is possible to prevent unnecessary power consumption generated to measure a handwriting pressure.

Description

Description INPUT PEN AND THE INPUT SYSTEM USING THE SAME

Technical Field

[1] The present invention relates to an input device, and more particularly, to an input pen used to input natural handwriting and an input system using the same. Background Art

[2] As electronic apparatuses such as a computer and a personal digital assistant (PDA) are popularized, users are accustomed to record important information or a contact list of acquaintances using such electronic apparatuses instead of pocket books.

[3] Especially, as electronic apparatuses such as a tablet PC or a PDA are popularized, users become able to directly input and record their own handwriting data on the electronic apparatuses such as a tablet PC or a PDA using a pen or the like rather than a keyboard. In addition to the handwriting, users become able to edit a simple picture or the like using various application programs such as Microsoft Paint or Paintbrush.

[4] However, according to such a conventional method of inputting handwriting data to electronic apparatuses such as a touch pad or a tablet PC, locus of an input means were simply displayed to a user by connecting locations of the input means. Therefore, the handwriting or a picture input by a user was recorded and displayed as a solid line having the same thickness, and it was impossible to provide a user with natural handwriting feeling such as thickness change of displayed characters generated by a pen pressure difference applied to a paper surface when a user actually performs handwriting.

[5] According to another conventional method to solve such a problem, a capacitor 130 was mounted on an end of a pen nib 110 of an input pen as shown in FIG. 1. In this method, when a user touches a paper with the pen nib 110 to input handwriting, pressure is applied to the pen nib 110, and also applied to the capacitor 130 provided in an end of the pen nib 110. The applied pressure generates change of a distance between both electrodes of the capacitor 130, and its capacitance is accordingly changed.

[6] The capacitor 130 is included in a portion of an RC oscillation circuit or an LC oscillation circuit of the oscillation circuit unit 140 shown in FIG. 1. Therefore, the oscillation frequency of the oscillation circuit unit 140 is also changed depending on the capacitance change, and the pressure applied to the pen nib 110 can be measured by examining change of the frequency in the input pen.

[7] According to the conventional methods described above, an element sensitive to change of capacitance C or inductance L depending on handwriting pressure should be mounted on a tip of a pen, and an oscillation frequency is changed depending on change of properties of the LC oscillation circuit. In this type of input pen, the pressure applied to the pen nib 110 can be measured by examining change of the frequency. Disclosure of Invention

Technical Problem

[8] The present invention provides an input pen capable of reducing power consumption by allowing measurement of pressure applied to a pen nib only when a user input handwriting on a paper surface using the input pen, i.e., only when pressure is applied to the pen nib.

[9] Also, the present invention provides an input pen capable of reducing power consumption and reliably measuring handwriting pressure of a user by preventing breakdown of a device even when a significant level of pressure is applied to the pen nib.

[10] Also, the present invention provides an input system capable of inputting natural handwriting using the input pen. Technical Solution

[11] According to an aspect of the present invention, there is provided an input pen comprising: a magnet mounted in an end of a pen nib; a magnetic force measurement unit which measures a magnetic flux density emanated from the magnet and outputs the magnetic flux density; and a control unit which measures a distance between the magnet and the magnetic force measurement unit using the magnetic flux density input from the magnetic force measurement unit, converts the distance into a pressure value, and outputs the pressure value.

[12] The input pen may further comprise a distance retaining member which is located between the magnet and the magnetic force measurement unit in order to constantly retain the distance between the magnet and the magnetic force measurement unit when no pressure is applied to the pen nib and recover the distance between the magnet and the magnetic force measurement unit when the pressure applied to the pen nib to reduce the distance between the magnet and the magnetic force measurement unit is removed.

[13] The input pen may further comprise a pressure sensing unit which senses whether or not pressure is applied to the pen nib, and outputs a pressure sensing signal when the pressure is applied to the pen nib, wherein the control unit outputs a control signal for instructing to supply power to the magnetic force measurement unit to allow the magnetic force measurement unit to measure a magnetic flux density only when the pressure sensing signal is applied.

[14] The pressure sensing unit may sense the pressure by examining whether or not a first conductor and a second conductor are electrically connected to each other, wherein the first conductor is provided in a casing internally storing the pen nib, and wherein the second conductor makes contact with the first conductor when no pressure is applied to the pen nib, and the second conductor is separated from the first conductor when pressure is applied to the pen nib.

[15] The input pen may further comprise a reference signal generation unit which generates and emanates a reference signal for a predetermined time period, and an ultrasonic signal generation unit which generates and emanates an ultrasonic signal in synchronization with the reference signal, wherein the control unit emanates the pressure value together with the reference signal.

[16] According to another aspect of the present invention, there is provided an input system comprising: the aforementioned input pen; and an input device which generates location data of the input pen using the reference signal and the ultrasonic signal received from the input pen, and stores the location data as handwriting data together with data on the pressure value received from the input pen.

Advantageous Effects

[17] As described above, according to the present invention, the pressure applied to the pen nib of the input pen is measured, and the pressure data is input as handwriting data together with location data. As a result, it is possible to more naturally input handwriting data. [18] Additionally, it is examined whether or not pressure is applied to the input pen. Only when pressure is applied to the input pen, it is determined that a user inputs handwriting, and measurement of the pressure applied to the input pen is allowed.

Therefore, it is prevented that power is consumed unnesessarily when the pressure is not applied.

Brief Description of the Drawings [19] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: [20] FIG. 1 illustrates a conventional structure of an input pen capable of measuring handwriting pressure; [21] FIG. 2 is a block diagram illustrating a functional structure of an input pen according to an exemplary embodiment of the present invention; [22] FIGS. 3 and 4 illustrate a physical structure of an input pen according to an exemplary embodiment of the present invention; [23] FIG. 5 illustrates a pressure sensing unit according to an embodiment of the present invention; and [24] FIG. 6 illustrates a natural handwriting input system using an input pen according to an exemplary embodiment of the present invention. Best Mode for Carrying Out the Invention

[25] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the attached drawings.

[26] FIG. 2 is a block diagram illustrating a functional structure of an input pen according to an exemplary embodiment of the present invention. FIGS. 3 and 4 illustrate a physical structure of an input pen according to an exemplary embodiment of the present invention.

[27] First, referring to FIG. 2, an input pen according to the present invention functionally includes a pressure sensing unit 210, a control unit 220, a power supply unit 250, a switching unit 230, and a magnetic force measurement unit 240.

[28] The input pen according to the present invention physically includes a pen nib 310 and a casing 320 which internally stores the pen nib 310 as well as the aforementioned functional units including the pressure sensing unit 210, the control unit 220, the power supply unit 250, the switching unit 230, and the magnetic force measurement unit 240.

[29] First, a functional structure according to the present invention will be described. The power supply unit 250 supplies power having a predetermined voltage level to the pressure sensing unit 210, the control unit 220, and the switching unit 230. The power supply unit 250 is preferably implemented using a battery. However, when the input pen of the present invention receives power from an input device which receives natural handwriting, the power supply unit 250 may be not included in the input pen.

[30] The pressure sensing unit 210 senses whether or not pressure is applied to the pen nib

310, and outputs an pressure sensing signal to the control unit 220 if the pressure is sensed.

[31] When the pressure sensing signal is input, the control unit 220 generates a control signal for instructing the switching unit 230 to output the power supplied from the power supply unit 250 to the magnetic force measurement unit 240 and outputs the control signal to the switching unit 230. Also, the control unit 220 measures a distance between the pen nib 310 and the magnetic force measurement unit 240 using the magnetic force measurement value input from the magnetic force measurement unit 240, and the converts the measured distance into a pressure value.

[32] The switching unit 230 outputs the power input from the power supply unit 250 to the magnetic force measurement unit 240 in response to the control signal applied from the control unit 220.

[33] The magnetic force measurement unit 240 measures a magnetic flux density emanated from a magnet 330 of the pen nib 310, and the magnetic flux density is output to the control unit 220. The magnetic force measurement unit 240 may be im- plemented using a sensor capable of sensing magnetic flux. According to an exemplary embodiment of the present invention, the magnetic force measurement unit 240 is implemented using a Hall sensor.

[34] FIG. 3 illustrates a physical structure of an input pen according to an exemplary embodiment of the present invention. Referring to FIG. 3, the input pen includes a pen nib 310 and a casing 320. The casing 320 internally stores the pen nib 310 as well as the aforementioned functional units including the pressure sensing unit 210, the control unit 220, the power supply unit 250, the switching unit 230, and the magnetic force measurement unit 240.

[35] A hole is provided in an end of the casing 320 in order to allow the pen nib 310 to be inserted into and stored in an internal cavity of the casing 320. A first conductor 382 is provided around a periphery of the hole as shown in FIG. 3.

[36] Additionally, a first support 340 made of an insulation material is connected to an end of the pen nib 310, and a magnet 330 is connected to the other end of the first support 340. A circumference of the junction plane between the first support 340 and the pen nib 310 is provided with a second conductor 384 which makes contact with and is electrically connected to the first conductor 382.

[37] On the other hand, inside the casing 320, a second support 350 is extended from an internal wall of the casing 320, and a surface of the second support 350 opposite to the pen nib 310 is provided with a magnetic force measurement unit 240. Additionally, the second support 350 may be internally provided with a thru-hole having a predetermined diameter so as to allow a wire for connecting the magnetic force measurement unit 240 to the switching unit 230 and a wire for connecting the magnetic force measurement unit 240 to the control unit 220 to pass through it.

[38] A distance retaining member 360 is provided between the first and second supports

340 and 350 in order to constantly retain the distance between the first and second supports 340 and 350. That is, a distance between the magnet 330 and the magnetic force measurement unit 240 is constantly retained. The distance retaining member 360 may be formed of a resilient material. When the pen nib 310 is pressed, the distance retaining member 360 is contracted in proportion to the pressure applied to the pen nib 310, and the distance between the first and second supports 340 and 350 is reduced. When the pressure applied to the pen nib 310 is removed, the distance retaining member 360 is returned to its initial position, so that the distance between the first and second supports 340 and 350 is constantly retained.

[39] According to an exemplary embodiment of the present invention, the distance retaining member 360 may be formed of a resilient spring, a rubber cylinder 360-2, or a silicon cylinder 360-2 having an internal cavity.

[40] Now, operation of the input pen according to an exemplary embodiment of the present invention will be described with reference to FIGS. 2 to 4. First, when a user does not touch a paper surface with the input pen, i.e., when a user is just holding the input pen without handwriting, the first and second supports 340 and 350 retains a constant distance due to a resilient force of the distance retaining member 360, and the first conductor 382 makes contact with the second conductor 384.

[41] On the other hand, when a user inputs handwriting using the input pen, the pen nib

310 makes contact with the paper surface and pressure is applied. While the applied pressure makes the distance retaining member 360 to be contracted, the pen nib 310 and the first support 340 cooperatively move into the internal side of the casing 320 of the input pen (i.e., toward the second support 350).

[42] As the pen nib 310 moves into the internal side of the casing 320, the first and second conductors 382 and 384 that have been connected are separated from each other.

[43] The pressure sensing unit 210 examines whether or not the first and second conductors 382 and 384 are electrically connected to each other to sense whether or not pressure is applied. As described above, when a user is just holding the input pen, the first and second conductors 382 and 384 are electrically connected to each other. In this state, the pressure sensing unit 210 determines that no pressure is applied.

[44] On the other hand, when pressure is applied, and the first and second conductors 382 and 384 are separated and electrically disconnected from each other, the pressure sensing unit 210 determines that pressure is applied, generates a pressure sensing signal, and outputs it to the control unit 220.

[45] The pressure sensing unit 210 may determine whether or not the first and second conductors 382 and 384 make contact with each other by measuring electric current flowing between the first and second conductors 382 and 384 or a voltage difference between the first and second conductors 382 and 384.

[46] For example, referring to FIG. 5, which illustrates an implementation of the pressure sensing unit 210, the first and second conductors 382 and 384 cooperatively function as a switch, and the pressure sensing unit 210 is implemented using a resistor R, so that a voltage at a point A is output to the control unit 220 as a pressure sensing signal.

[47] When no pressure is applied, the first and second conductors 382 and 384 make contact with each other, and electric current flows through the resistor R to the ground, so that a voltage at a point A becomes OV. However, when pressure is applied, the first and second conductors 382 and 384 are separated from each other, and a voltage at a point A becomes Vcc (e.g., 5V). Therefore, a voltage corresponding to Vcc is output to the control unit 220 as a pressure sensing signal, and the control unit 220 receives the pressure sensing signal and outputs a control signal to the switching unit 230.

[48] On the other hand, when pressure is applied to the pen nib 310, and the pressure sensing signal is output from the pressure sensing unit 210 to the control unit 220, the control unit 220 outputs the control signal to the switching unit 230. Also, the switching unit 230 connects the power supply unit 250 to the magnetic force measurement unit 240 to supply power to the magnetic force measurement unit 240.

[49] When power is supplied from the power supply unit 250 to the magnetic force measurement unit 240 through the switching unit 230, the magnetic force measurement unit 240 measures a magnetic flux density emanated from the magnet 330 attached to the first support 340 and outputs the magnetic flux density to the control unit 220.

[50] As described above, the pen nib 310 moves into the internal side of the casing 320 in response to the pressure applied when a user performs handwriting on a paper surface using the input pen.

[51] As the pen nib 310 moves, the distance between the magnet 330 and the magnetic force measurement unit 240 is reduced, and the magnetic flux density measured by the magnetic force measurement unit 240 increases. Also, when a user further presses the input pen, and the handwriting pressure becomes stronger, the distance between the magnet 330 and the magnetic force measurement unit 240 further decreases, and the magnetic flux density measured by the magnetic force measurement unit 240 further increases. When the handwriting pressure decreases, the distance between the magnet 330 and the magnetic force measurement unit 240 increases due to a resilient force of the distance retaining member 360, and the magnetic flux density measured by the magnetic force measurement unit 240 decreases.

[52] On the other hand, the control unit 220 measures the distance between the magnet

330 and the magnetic force measurement unit 240 using the measurement value of the magnetic flux density input from the magnetic force measurement unit 240, and generates handwriting pressure in inverse proportion to the measurement distance. In this case, as the handwriting pressure increases, the distance between the magnet 330 and the magnetic force measurement unit 240 decreases, and the measurement value of the magnetic force measurement unit 240 increases. As the handwriting pressure decreases, the distance between the magnet 330 and the magnetic force measurement unit 240 increases, and the measurement value of the magnetic force measurement unit 240 decreases.

[53] The control unit 220 transmits data on the generated handwriting pressure to the input device in a wired/wireless manner, so that the data on the handwriting pressure can be used in the input device together with data on the locus of the input pen.

[54] FIG. 6 illustrates an example of a natural handwriting input system using an input pen according to the present invention. The natural handwriting input system comprises an input pen 600 and an input device 500. The input pen 600 further includes a reference signal generation unit and an ultrasonic signal generation unit in addition to the aforementioned components according to the present invention. [55] Referring to FIG. 6, the control unit 220 of the input pen 600 generates a control signal, and outputs the control signal to the reference signal generation unit 260 and the ultrasonic signal generation unit 270. The control signal instructs to generate the reference signal and the ultrasonic signal for a predetermined time period.

[56] When the control signal is input from the control unit 220, the reference signal generation unit 260 and the ultrasonic signal generation unit 270 simultaneously generate the reference signal and the ultrasonic signal, respectively, and emanate them to the air.

[57] Additionally, if the pressure sensing signal is input from the pressure sensing unit

210 while a user touches a paper surface with the input pen 600 and performs handwriting, the control unit 220 converts the measurement value input from the magnetic force measurement unit 240 as described above into a pressure value, and transmits it to the input device 500 together with the reference signal.

[58] On the other hand, the input device 500 includes a receiving sensor 510 which receives the reference signal and a plurality of receiving sensors 520a and 520b which receive the ultrasonic signal. In this case, the ultrasonic signal receiving sensors 520a and 520b are separated from each other in a predetermined distance.

[59] A coordinate value (x, y) of the input pen 600 on a 2-dimensional plane can be obtained as follows:

[60] [Equation 1]

9 9 9

[61] a²=x²+y²

[62] b²=(c-x)²+y²

[63] In Equation 1, assuming that an infrared ray or radio frequency signal used as the reference signal propagates the air at the speed of light, and the reference signal is generated from the input pen 600 and received by the reference signal receiving sensor 510 in synchronization with the ultrasonic signal, the distances a can be obtained by multiplying the speed of soung by a time difference between a time point at which the reference signal is received and a time point at which the ultrasonic signal is received by the left-hand ultrasonic sensor 520a, and the distances b can be obtained by multiplying the speed of soung by a time difference between a time point at which the reference signal is received and a time point at which the ultrasonic signal is received by the left-hand ultrasonic sensor 520b. Since the distance c is previously determined, the coordinate value (x, y) can be obtained by applying the values a, b, and c to Equation 1.

[64] On the other hand, the input device 500 changes only a location of a cursor depending on the coordinate value of the input pen 600 when only the reference signal and the ultrasonic signal are received from the input pen 600. The input device 500 internally stores the pressure value as handwriting data together with the coordinate value of the input pen 600 when the pressure value is received from the input pen 600 in addition to the reference signal and the ultrasonic signal, so that the handwriting is displayed on a screen according to the handwriting data.

[65] The input device 500 may present a bold line to a user during handwriting display operation when the pressure value is high. Also, the input device 500 presents a narrow line to a user during handwriting display operation when the pressure value is low. As a result, the handwriting can be input and reproduced with more reality.

[66] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

[67] For example, although, in the aforementioned embodiments, the first conductor is provided around the inner periphery of the hole, and the second conductor is provided around the outer circumference of the pen nib, the first and second conductors may be constructed to make contact with each other when no pressure is applied only to a predetermined area around the hole and a predetermined area around the first support. Also, it should be noted that the first and second conductors can be provided in any location if they could make contact with each other when no pressure is applied to the pen nib, and they could be separated from each other when pressure is applied to the pen nib.

[68] The exemplary embodiments should be considered in descriptive sense only and not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

Claims

[ 1 ] An input pen comprising: a magnet mounted in an end of a pen nib; a magnetic force measurement unit which measures a magnetic flux density emanated from the magnet and outputs the magnetic flux density; and a control unit which measures a distance between the magnet and the magnetic force measurement unit using the magnetic flux density input from the magnetic force measurement unit, converts the distance into a pressure value, and outputs the pressure value.

[2] The input pen according to claim 1, further comprising a distance retaining member which is located between the magnet and the magnetic force measurement unit in order to constantly retain the distance between the magnet and the magnetic force measurement unit when no pressure is applied to the pen nib and recover the distance between the magnet and the magnetic force measurement unit when the pressure applied to the pen nib to reduce the distance between the magnet and the magnetic force measurement unit is removed.

[3] The input pen according to claim 1, further comprising a pressure sensing unit which senses whether or not pressure is applied to the pen nib, and outputs a pressure sensing signal when the pressure is applied to the pen nib, wherein the control unit outputs a control signal for instructing to supply power to the magnetic force measurement unit to allow the magnetic force measurement unit to measure a magnetic flux density only when the pressure sensing signal is applied.

[4] The input pen according to claim 3, wherein the pressure sensing unit senses the pressure by examining whether or not a first conductor and a second conductor are electrically connected to each other, wherein the first conductor is provided in a casing internally storing the pen nib, and wherein the second conductor makes contact with the first conductor when no pressure is applied to the pen nib, and the second conductor is separated from the first conductor when pressure is applied to the pen nib.

[5] The input pen according to claim 1, further comprising a reference signal generation unit which generates and emanates a reference signal for a predetermined time period, and an ultrasonic signal generation unit which generates and emanates an ultrasonic signal in synchronization with the reference signal, wherein the control unit emanates the pressure value together with the reference signal.

[6] An input system comprising: the input pen according to claim 5; and an input device which generates location data of the input pen using the reference signal and the ultrasonic signal received from the input pen, and stores the location data as handwriting data together with data on the pressure value received from the input pen.