Abstract:
A dual mode apparatus for writing on paper, inputting information to a host electronic device, and/or controlling applications on a host electronic device. The apparatus is preferably constructed and arranged as a combination pen and active stylus that includes a pen refill cartridge and an active stylus module. The pen refill cartridge comprises a body configured for storing ink and a ball-point assembly for dispensing the ink on a writing surface or physical media. The active stylus module is configured to transmit signals to the ball-point assembly of the pen refill cartridge. The ball-point assembly may include an antenna, optical transducer or ultrasonic transducer. In one expedient, the signals may be radio signals characterizing a force applied to the ball-point assembly, the level of a battery or the level of ink in the pen refill cartridge.

Description:
BACKGROUND 
     Stylus pointing devices are utilized to input information and/or to control applications executing on a host electronic device. A stylus may be characterized as active or passive. An active stylus emits signals that are detected by the host device and processed to control an application. A passive stylus modifies an electrical property, such as the capacitance or resistance of a display surface or assembly of the host device. When the stylus tip is brought into close proximity to the display, the position thereof can be determined in several ways, such as, for example by: the effect of the stylus on the electrical properties of the display (i.e., by sensing electromagnetic induction, changes in electrical resistance, variance in electrical capacitance, and the like); changes in the optical properties of the tablet; processing ultrasonic/optical signals, etc. 
     In the instance of an active stylus that emits radio signals, a radio transmitter associated with the stylus generates and radiates an electromagnetic field that is sensed and processed by the host to yield a stylus position. 
     Since conventional writing implements cannot be used with an electronic host device, a user must have both a pen and stylus when writing and using an electronic device. It would therefore be desirable to provide a dual-mode stylus and pen that can be employed in both environments, thereby eliminating the need to carry both. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the disclosure will be described below with reference to the included drawings such that like reference numerals refer to like elements and in which: 
         FIG. 1  is a schematic diagram of an exemplary drawing system, in accordance with aspects of the disclosure; 
         FIG. 2  is a schematic diagram of an illustrative combination ball-point pen and active stylus, in accordance with an aspect of the disclosure; 
         FIG. 3  is a schematic diagram of an exemplary active refill cartridge in accordance with an aspect of the disclosure; 
         FIG. 4  is a block diagram of an exemplary circuit assembly for an active stylus in accordance with an aspect of the disclosure; 
         FIG. 5  is a sectional view of an exemplary pen active refill cartridge in accordance with an aspect of the disclosure; 
         FIG. 6  is a sectional view of a further exemplary pen active refill cartridge; 
         FIG. 7  is a schematic view of an active refill cartridge; 
         FIG. 8  is a flow chart of a method of operation for an active refill cartridge in accordance with an aspect of the disclosure; 
         FIG. 9  is a block diagram of an active stylus in accordance with an aspect of the disclosure; 
         FIG. 10  is a sectional view of a two-part active pen refill cartridge with an ink level sensor in accordance with an aspect of the disclosure; 
         FIG. 11  is a sectional view of a pen refill cartridge in accordance with an aspect of the disclosure; 
         FIG. 12  is a schematic diagram of a pen refill cartridge including an ink level sensor in accordance with an aspect of the disclosure; and 
         FIG. 13  is a further schematic diagram of a pen refill cartridge including an ink level sensor in accordance with an aspect of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. Numerous details are set forth to provide an understanding of the illustrative embodiments described herein. The embodiments may be practiced without these details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the disclosed embodiments. The description is not to be considered as limited to the scope of the embodiments shown and described herein. 
     In accordance with an aspect of the disclosure a writing implement is provided that enables a user to write on paper and provide inputs to a host electronic device. The writing implement is a combination pen and active stylus that includes a pen refill cartridge and an active stylus module comprising at least one element for generating signals that are sensed and processed by the host device. The pen refill cartridge comprises a hollow body configured to store ink and a ball-point assembly configured to receive the ink from the body. The active stylus module is configured to electrically couple to the ball-point assembly of the pen refill cartridge and operable to transmit signals to the ball-point assembly. In an illustrative embodiment, the signals are radio signals, and the active stylus module electrically communicates with the ball-point assembly of the pen refill cartridge via an electrically insulated conductor, such that the radio signals are radiated from the tip of the writing implement. In other embodiments, the ball-point assembly includes a light emitting diode, configured to generate an optical signal, or an ultrasonic transducer, operable to generate ultrasonic signals that may be sensed by the host device. 
       FIG. 1  is a schematic diagram of an exemplary drawing system  100  in accordance with an aspect of the disclosure. In  FIG. 1 , a writing implement  102  is manipulated by a user  104  to draw a line or other image  106  on display screen  108  of host electronic device  110 . The display screen  108  is responsive to a signal transmitted from a tip  112  of the combination pen and active stylus  102 . In one embodiment, the host electronic device includes a radio frequency sensor grid. Other embodiments may utilize infra-red, optical or ultrasonic sensors, for example. The display screen  108  may also include a capacitive or resistive touch screen, for example. Host electronic device  110  may be, for example, a laptop computer, tablet computer (tablet), mobile telephone, smart-phone, personal digital assistant (PDA), or other portable or non-portable electronic device. 
     In operation, display screen  108  of the host electronic device  110  senses one or more touch positions at which the combination pen and active stylus  102  touches, or is brought into close proximity with, the display screen  108 . 
       FIG. 2  is a schematic diagram of a combination ball-point pen and active stylus, in accordance with exemplary embodiments of the disclosure. The combination ball-point pen and active stylus  102  includes active refill cartridge  202  and pen housing  204 . In operation, active refill cartridge  202  is placed inside pen housing  204  and the lower pen housing  206  and upper pen housing  208  are screwed together. Once assembled, ball-point assembly  210  of the cartridge  202  protrudes from an aperture in the end of the lower pen housing  206 . In accordance with one aspect of the disclosure, the combination ball-point pen and active stylus  102  enables writing on paper or on a display of an electronic device. When the combination ball-point pen and active stylus  102  is moved across paper, friction between the paper and a ball of the ball-point assembly  210  causes the ball to rotate and transfer ink from the cartridge  202  to the paper. However, the viscosity of the ink within the cartridge is selected such that when the combination ball-point pen and active stylus  102  is moved across a display surface of a tablet, smart-phone, or other electronic device, there is insufficient friction to overcome the surface tension of the ink and no ink is transferred to the display surface. Instead, a stylus signal is transmitted from the ball-point assembly  210 . In one embodiment, the ball-point assembly  210  operates as a radio antenna to enable communication with a host electronic device. The pen housing  204  may include a retraction mechanism  212  operable to move the tip between an advanced position, where the tip protrudes from the pen housing to allow deposition of writing material on a surface, and a retracted position, where the tip is disposed within the pen housing. A sensor  214  may be used to detect whether the tip is in the advanced or retracted position. A view through the cross-section  3 - 3  is shown in  FIG. 3 . 
       FIG. 3  is a sectional view of an exemplary active pen refill cartridge  202 . The active pen refill cartridge  202  comprises a hollow body  302  configured to contain ink  304 . The ink  304  is supplied to ball-point assembly  210  to enable writing on paper. A circuit assembly  306  is operable to transmit a stylus signal to the ball-point assembly  210  to enable electronic drawing or writing. The stylus signal may be transmitted via a wire, via the hollow body  302 , or via a surface coating on the hollow body  302 . In this embodiment, the circuit assembly  306  is powered by battery  308 . The battery  308  may be electrically coupled to the circuit assembly  306  via one or more electrical connections  310 . In one embodiment, the hollow body  302 , or a coating on the hollow body, is electrically conductive and may be used to couple one pole of the battery, such as the ground, to the circuit assembly. The battery  308  may be located in a battery compartment  316  at the end of the hollow body  302  to facilitate easy replacement of the battery  308 . A terminal or contact pad  318  may be used to couple the battery to the circuit assembly  306 . 
     In one embodiment, the circuit assembly  306  is immersed in the ink  304 . This configuration maximizes the amount of ink contained in the cartridge. 
     The battery may be coupled to the circuit assembly via a switch. The switch may be, for example, included in a force sensing mechanism  312 . In this embodiment, the force sensing mechanism  312  is mechanically coupled to the ball-point assembly  210  via shaft  314 . The shaft may be electrically conductive and used to provide an electrical coupling between the circuit assembly  306  and the ball-point assembly  210 . A compliant element  320  reduces the mechanical coupling between the ball-point assembly  210  and the end of the hollow body  302 , so that a force applied to the ball-point assembly  210  is transferred to the force activated switch  312  via shaft  314 . Additionally, the element  320  may be an electrical insulator that prevents the stylus signal, supplied to the ball-point assembly  210 , from being electrically coupled to the hollow body  302 . This enables hollow body  302  to be used as power supply conductor. For example, the hollow body  302  may be coupled to a battery and used as an electrical ground or supply voltage. 
     In some embodiments, the force-sensing mechanism  312  further comprises a sensor configured to sense forces applied to the ball-point assembly  210 . When used as an active stylus, the circuit assembly is operable to generate a stylus signal that is descriptive of the force applied to the ball-point assembly  210 . The force signal may be utilized by a host electronic device to control selected features of a drawing or writing application executed on the host electronic device. 
       FIG. 4  is a block diagram of an exemplary circuit assembly of an active stylus. The circuit assembly  306  includes a control module  400 , which may be a micro-controller, a system on a chip (SoC), an assembly of discrete components, an assembly of integrated circuits or a combination thereof, for example. The control module  400  includes power management unit (PMU)  402 , which receives power from an external power supply, such as battery  308 , and a clock system (CLK S)  404  that receives a timing signal from a crystal (XTAL)  406 . The clock system is utilized, for example, to supply an instruction clock to processing core  408 . The clock system  404  may also supply a timing signal to a radio transmitter  410 . The radio transmitter  410  supplies a radio signal to the ball-point assembly  210 . The ball-point assembly  210  operates as an antenna to transmit the radio signal to a host electronic device. The control module  400  also includes an analog-to-digital converter  412 , operable to sample a force signal  414  from force-sensing mechanism  312 . The force signal  414  is representative of a force applied to the ball point assembly  210 , which is mechanically coupled to the force sensing mechanism via coupling  314 . The force-sensing mechanism  312  may also receive a signal  416  from the control module  400  via digital-to-analog converter  418 . 
     In the embodiment shown in  FIG. 4 , an analog-to-digital converter  412  is used to provide a digital representation of the force signal. The digital representation may comprise one or more bits. For example, an 8-bit converter might be used. When a single bit is used to indicate whether the force signal is above or below a threshold value, the analog-to-digital converter  412  may be replaced by a switch. 
     The power management unit  402  may incorporate a battery monitor. An indicator of the battery level may be embedded in the stylus signal and communicated to a host electronic device. The host electronic device can then display the battery level to a user, via the display screen, to facilitate timely battery replacement. 
     A further aspect of the disclosure relates to a writing implement comprising a pen refill cartridge and an active stylus cartridge that are constructed and arranged to fit together within a pen housing. The pen refill cartridge has a hollow body, adapted to contain ink, and a ball-point assembly configured to receive ink from within the hollow body and further configured to receive a stylus signal. A terminal at one end of the cartridge enables a stylus signal from the active stylus cartridge to be electrically coupled to the ball-point assembly. The active stylus cartridge includes a circuit assembly operable to produce a stylus signal, and a terminal is located at one end of the cartridge enables the stylus signal to be electrically coupled to the pen refill cartridge. 
       FIG. 5  is a sectional view of an exemplary active pen refill cartridge  202 , in accordance with an aspect of the disclosure. The active pen refill cartridge  202  is arranged in two-parts, comprising a signal generation cartridge  502  and antenna/ink cartridge  504 . This embodiment facilitates replacement of the ink cartridge  504  without having to replace the signal generation cartridge  502 . 
     The antenna/ink cartridge  504  comprises a hollow body  302 ′ configured to contain ink  304 . The ink  304  is supplied to ball-point assembly  210  to enable writing on paper. Electrical conductor  506  couples a stylus signal from terminal  508  to the ball-point assembly  210 . The stylus signal may be transmitted via a wire, via the hollow body  302 ′, or via a surface coating on the hollow body  302 ′. 
     The signal generation cartridge  502  comprises a body  302 ″ that houses circuit assembly  306 . The circuit assembly  306  is operable to transmit a stylus signal to antenna/ink cartridge  504  via terminal  510 , which aligns with electrical coupling  508  of antenna/ink cartridge  504  when the cartridges are aligned within a pen housing. The circuit assembly  306  is powered by battery  308 . In operation, signal generation cartridge  502  and antenna/ink cartridge  504  are aligned in series inside a pen housing, such that a force applied to the ball-point assembly  210  pushes stop element  512  against an interior surface of the pen housing and produces a force across force-sensing mechanism  312 . The force-sensing mechanism  312  may include a force-activated switch and/or a force sensor operable to sense the force applied to the ball-point assembly  210 . The force activated switch may be used to switch power to the circuit assembly  306 . If no force is applied for a set period of time, the circuit assembly is de-powered. This enables the active stylus to be used in a ‘hover’ mode, in which the ball-point assembly is close to, but not touching, a display screen of an electronic device. When used as an active stylus, the circuit assembly is operable to generate a stylus signal that is descriptive of the force applied to the ball-point assembly  210 , as sensed by the force-sensor of the force-sensing mechanism  312 . The force signal may be utilized by a host electronic device to control selected features of a drawing or writing application executed on the host electronic device. 
     The battery  308  may be placed in series with the force sensor, so that forces are coupled to the sensor through the battery, or the battery may be placed at other locations in the hollow body  302 ″. The battery and housing therefor may be configured to enable easy replacement of the battery. 
     A stylus identifier may be embedded within the stylus signal and transmitted to a host device. The identifier may be type identifier and/or a unique identifier the stylus. 
       FIG. 6  is a sectional view of an active an exemplary pen active refill cartridge  202  in accordance with an aspect of the disclosure. The active pen refill cartridge  202  comprises signal generation cartridge  502  and antenna/ink cartridge  504 . This embodiment allows the antenna/ink cartridge  504  to be replaced without having to replace the signal generation cartridge  502 , and allows the battery to be replaced at the same time. 
     The antenna/ink cartridge  504  comprises hollow body  302 ′ configured to contain ink  304 . The ink  304  is supplied to ball-point assembly  210  to enable writing on paper. Electrical conductor  506  couples a stylus signal from terminal  508  to the ball-point assembly  210 . The stylus signal may be transmitted via a wire, via the hollow body  302 ′, or via a surface coating on the hollow body  302 ′. Battery  308  is electrically coupled to one or more terminals  602  to enable power to be supplied to the signal generation cartridge  502 . 
     The signal generation cartridge  502  comprises body  302 ″ that houses circuit assembly  306 . The circuit assembly  306  is operable to transmit a stylus signal to antenna/ink cartridge  504  via terminal  510 , which aligns with electrical coupling  508  of antenna/ink cartridge  504 . In operation, signal generation cartridge  502  and antenna/ink cartridge  504  are aligned in series inside a pen housing, such that a force applied to the ball-point assembly  210  pushes force-sensing mechanism  312  against an interior surface of the pen housing. The force-sensing mechanism  312  may include a force-activated switch and/or a force sensor operable to sense the force applied to the ball-point assembly  210 . The force activated switch may be used to switch power to the circuit assembly  306 . In this embodiment, the circuit assembly  306  is powered by battery  308  that is electrically coupled to the circuit assembly, through the force activated switch, when the one or more terminals  604  make contact with the mating terminals  602 . If no force is applied for a set period of time, the circuit assembly is de-powered. This enables the active stylus to be used in a ‘hover’ mode, in which the ball-point assembly is close to, but not touching, a display screen of an electronic device. When used as an active stylus, the circuit assembly is operable to generate a stylus signal that is descriptive of the force applied to the ball-point assembly  210 , as sensed by the force-sensor of the force-sensing mechanism  312 . The force signal may be utilized by a host electronic device to control selected features of a drawing or writing application executed on the host electronic device. 
       FIG. 7  shows an exemplary two-part active pen refill cartridge in accordance with an aspect of the disclosure. The active pen refill cartridge comprises signal generation cartridge  502  and antenna/ink cartridge  504 . The cartridges are shown positioned within the body of pen  102 . The cartridges are electrically coupled through terminal  510  of signal generation cartridge  502  and terminal  508  of antenna/ink cartridge  504 , enabling a stylus signal generated in signal generation cartridge  502  to be coupled to the antenna of antenna/ink cartridge  504 . Additional electrical connections may be used if the battery is located in antenna/ink cartridge  504 . A bias element  702  (such as a spring) holds the cartridges in the correct position and relieves force on the force-activated switch  512  when no force is applied to the ball-point assembly  210 . In use, a force applied to ball-point assembly  210  is transferred to cartridge  502  and compresses bias element  702 . This activates force-activated switch  512  to power the signal generation cartridge  502 . Signal generation cartridge  502  may remain powered for a period of time after the force is removed from ball-point assembly  210 . 
     In one embodiment, the signal generation cartridge  502  is provided with an on/off switch that may be activated by user when the cartridge is removed from the pen body  102 . This enables battery power to be conserved when writing on paper. 
     In another embodiment, the signal generation cartridge  502  may be powered on or off by tapping the ball-point assembly on a surface a set number of times within a period of time. Again, this enables battery power to be conserved when writing on paper. 
     In a further embodiment, the signal generation cartridge  502  is permanently powered. 
       FIG. 8  is a flow chart  800  of a method of operation of a combination active stylus and ball-point pen. At start block  802 , the circuit assembly is powered-off or in a low power mode, so as to conserve battery life. Following start block  802 , a start condition is detected at decision block  804 . The start condition may be, for example, a user-activated switch, a force-activated switch, or tapping of the ball-point assembly on a surface. At block  806 , the circuit assembly is powered to enable full operation. If the start condition is caused by a force activated switch, a timer is reset at block  808 . The timer allows the circuit assembly to remain powered for a period of time after a start condition is detected. Optionally, at block  810 , the force applied to the ball-point assembly is sensed, using the force-sensing mechanism, and at block  812  a stylus signal is generated. The stylus signal, which may be representative of the force applied to the ball-point assembly, is transmitted to the antenna at block  814 . At decision block  816 , a stop condition is detected. The stop condition may be, for example, a user-activated switch, an absence of force on a force-activated switch, or tapping of the ball-point assembly on a surface. If a stop condition is not detected, as depicted by the negative branch from decision block  816 , flow returns to block  808  and the timer is reset. If the stop condition is caused by a force activated switch, a check is made at decision block  818  to determine if the timer has expired. If the timer has expired, as depicted by the positive branch from decision block  818 , the circuit assembly is de-powered or enters a low power operating mode at block  820 . Similarly, if the stop condition is the result of a user-activated switch or tapping of the ball-point assembly on a surface, the timer expiration period may be set to zero so that flow continues to block  820  when the stop condition is detected. 
       FIG. 9  is a block diagram of an exemplary active stylus. The circuit assembly  306  includes a control module  400 , which may be a micro-controller, a system on a chip (SoC), an assembly of discrete components, an assembly of integrated circuits or a combination thereof, for example. In this embodiment, the stylus communicates with a host electronic device using near field communication (NFC) and the control module  400  is powered from a remote power source. The remote power source comprises a plurality of inductors  902  close to the surface of the display screen  108  of a host electronic device. In operation, when stylus tip  210  is positioned close to the inductor  902  of the host, the electromagnetic field produced by the inductor  902  of the host induces a current in an inductor  904  in the tip of the stylus. The induced current is supplied to power management unit (PMU)  402  to produce power supply  906  for the control module  400 . The radio transmitter  410  supplies a radio signal to the ball-point assembly  210 . This may be used to modify a property of the inductor  904  (such as the inductance, resistance, current etc) that may be sensed by the host electronic device. 
     In this embodiment, the stylus position is only detected when the stylus tip is close to display screen  108  of a host electronic device. The stylus is inactive otherwise. By placing a sheet of paper over the display screen  108 , a user may simultaneously create a drawing on the paper and on the electronic device. 
       FIG. 10  is a sectional view of an illustrative two-part active pen refill cartridge  202  in accordance with an aspect of the disclosure. In this embodiment, the pen refill cartridge  504  incorporates an ink level sensor comprising a first probe  1002  electrically coupled to a first terminal  1004 , and a second probe  1006  electrically coupled to a terminal  1008 . Ink  304  is electrically conductive and completes a circuit between the first and second probes. The resistance of the circuit is dependent upon the amount of ink in the cartridge—a full cartridge will have a lower resistance than an empty or partially empty cartridge. In operation, the first and second probes ( 1002 ,  1006 ) are coupled to signal generation cartridge  502 , via terminal  1010  and  1012 , which in turn is operable to sense the resistance between the two probes. A signal indicative of the ink level may be embedded in the stylus signal and transmitted to a host electrical device via the ball-point assembly  210 . 
       FIG. 11  is a sectional view through at lines  11 - 11  shown in  FIG. 10 . Ink  304  is contained within the hollow body  302 ′ and forms an electrical connection between first probe  1002  and second probe  1004 . The first and second probes may be implemented as coatings or traces on the non-conducting interior of the hollow body  302 ′. The width of the probes, or the spacing between the probes, may be varied in different implementations and may be selected dependent upon the electrical properties of the ink and/or the probes. For example, wider probe spacing may be used for a more conductive ink. Once the resistance between the probes is determined, the information may be embedded in a stylus signal transmitted along insulated conductor  506  to the ball point assembly. 
     In a further embodiment, conductor  506  is not insulated, and the ink level is determined by measuring the resistance between the conductor  506  and a single probe. 
     In a yet another exemplary embodiment as shown in  FIG. 12 , the pen refill cartridge  504  incorporates a sensor for determining when the ink level is low. In this embodiment, a first probe  1202  located in the hollow body  302 ′ is electrically coupled via insulated conductor  1204  to a first terminal  1206  and a second probe  1208  is electrically coupled via insulated conductor  1210  to a second terminal  1212 . Conductive ink  304  provides an electrical connection between the first and second probes when the ink level is above the level of the probes. However, no connection is provided when the ink level is below the level of the probes. The absence of a connection indicates that the ink level is low, and this information may be communicated to a host electronic device via the stylus signal. The first and second probes may be spaced apart in the longitudinal or circumferential directions of the hollow body  302 ′ and may be any shape. For example, longitudinally spaced rings, or circumferentially spaced pads may be used. 
       FIG. 13  is a further view of a pen refill cartridge  504  incorporating a sensor for determining when the ink level is low. In this embodiment, a first probe  1202  located in the hollow body  302 ′ is electrically coupled via insulated conductor  1204  to a first terminal  1206  and a second probe  1208  is electrically coupled via insulated conductor  1210  to a second terminal  1212 . Conductive ink  304  provides an electrical connection between the first and second probes when the ink level is above the level of the probes. However, no connection is provided when the ink level is below the level of the probes. The absence of a connection indicates that the ink level is low, and this information may be communicated to a host electronic device via the stylus signal. The first and second probes may be spaced apart in the longitudinal or circumferential directions of the hollow body  302 ′ and may be any shape. Circumferentially spaced pads are used in the exemplary embodiment shown. 
     The implementations of the disclosure described above are intended to be merely exemplary. It will be appreciated by those of skill in the art that alterations, modifications and variations to the illustrative embodiments disclosed herein may be made without departing from the scope of the disclosure. Moreover, selected features from one or more of the above-described embodiments may be combined to create alternative embodiments not explicitly shown and described herein. 
     The disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described exemplary embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.