ELECTRONIC PEN

Abstract: An electronic pen (20) for generating a signal corresponding to handwriting of an operator, including a pen body (22), which is grasped and manipulated by the operator in a manner similar to that which the operator would use to write on a page. A pen head (28), coupled to the body, is brought into contact with a surface and is held generally stationary in contact therewith while the operator manipulates the pen body. A transducer (32) is coupled to the pen body so as to generate the signal responsive to the manipulation thereof.

Description: ELECTRONIC PEN FIELD OF THE INVENTION The present invention relates generally to the conversion of written information to a digital format, and specifically to the conversion of written characters to digital signals. BACKGROUND OF THE INVENTION Systems for converting handwriting to digital format, as the handwriting is being produced, are well .known in the art. Typically, the two-dimensional position of a pen or stylus is transmitted in real-time to a processing unit as an operator writes with the pen or stylus on a position-sensitive pad. The processing unit uses the position and associated time as the inputs for translating the handwritten infoimation initially to alphanumeric characters, and then to standard digital signals. 3Com Corp., of Mountain View, CA, produce a hand-held computing device called a PalmPilot Professional. The PalmPilot Professional comprises a stylus and an electronic writing pad approximately 6 cm wide by 9 cm long. Data may be entered into the PalmPilot Professional using the stylus as a writing tool. Apple Computer Inc., of Cupertino, CA. produce a device called an Apple MessagePad. The MessagePad comprises a writing pad measuring approximately 10 cm by 20 cm, and a stylus. Handwriting may be inscribed on the MessagePad using the stylus, and a built-in processor translates the handwriting to standard digital characters by using built-in handwriting recognition software. SUMMARY OF THE INVENTION It is an object of some aspects of the present invention to provide improved methods and apparatus for translating handwriting to electrical signals. It is a further object of some aspects of the present invention to provide improved methods and apparatus for translating handwriting to digital alphanumeric characters. In some preferred embodiments of the present invention, a hand-held pen is held by an operator so that a tip of the pen is fixedly positioned against any surface. While keeping the tip fixed against the surface, the operator "writes" with the pen by exerting a lateral force on the pen, preferably causing a joint within the pen to flex responsive to the force. A transducer inside the pen measures flexure of the joint and/or the lateral force associated with such flexure. Measurements made by the transducer are received and analyzed by a processing unit, which preferably translates the measurements into one or more digital alphanumeric characters. Thus, in preferred embodiments of the present invention, the operation of writing is considered to be a process of exerting a series of forces on a substantially fixed pen. In analyzing the transducer measurements, the processor preferably determines an effective position that would have been achieved by the pen due to the lateral force and analyzes a plurality of effective position data produced over time. Unlike other systems known in the art for translating handwriting to digital characters, the present invention does not use a separate position sensing surface for determining the position of the tip of the pen, and does not require lateral motion of the pen. Therefore, the present invention is substantially more compact and can be operated in significantly smaller spaces than such systems. In some preferred embodiments of the present invention, the processing unit is contained inside the pen. Preferably, the pen further comprises a display, such as a liquid crystal display, mounted on an external surface of the pen. As the pen is operated, a written character is translated by the processing unit to a corresponding digital character signal, and the signal is then transmitted to the display, so that the operator is able to see the character generated. The present invention will be more fully understood from the following detailed description of the preferred embodiments thereof, taken together with the drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic pictorial view of an electronic pen, in accordance with a preferred embodiment of the present invention; Fig. 2 A is a schematic cross-sectional view of a pen tip corresponding to the pen of Fig. 1; Fig. 2B is a schematic exploded view of the pen tip of Fig. 2 A; Fig. 3 is a schematic pictorial view of an electronic pen, in accordance with an alternative preferred embodiment of the present invention; Fig. 4A is a schematic cross-sectional view of a pen tip in a non-operational state, corresponding to the pen of Fig. 3; Fig. 4B is a schematic cross-sectional view of the pen tip of Fig 4A in an operational state, corresponding to the pen of Fig. 3; Fig. 5 is a schematic pictorial view of an electronic pen, in accordance with a further alternative preferred embodiment of the present invention; Fig. 6 A is a schematic cross-sectional view of the pen of Fig. 5, taken along a line VIA - VIA in Fig. 5; Fig. 6B is a schematic exploded view of the pen of Fig. 5; Fig. 6C is a schematic view of a pressure sensor in the pen of Fig. 5, taken along a line VIC - VIC in Fig. 6B; Fig. 7 is a schematic external view of an electronic pen, in accordance with an alternative prefeired embodiment of the present invention; Fig. 8 A is a schematic cross-sectional view of the pen of Fig. 7; Fig. 8B is a schematic exploded view of the pen of Fig. 7; Fig. 9A is a schematic external view of a pen, in accordance with a further alternative preferred embodiment of the present invention; Fig. 9B is a schematic cross-sectional view of the pen of Fig. 9A; Fig. 10A is a schematic cross-sectional view of a pen, in accordance with an alternative preferred embodiment of the present invention; Fig. 1 OB is a schematic exploded view of a pen head of the pen of Fig. 10 AL, Fig. IOC is a schematic cross-sectional view of the pen head of Fig. 10.A in the act of writing; and Fig. 10D is a schematic sectional view of the pen head of Fig. IOC taken along a line XD - XD. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference is now made to Fig. 1, wliich is a schematic pictorial view of a pen 20, in accordance with a preferred embodiment of the present invention. Pen 20 is most preferably in the form of a cylinder having dimensions of the order of 15 mm diameter and 15 cm length, alternatively, pen 20 is in the foim of a polygonal prism of similar dimensions. Pen 20 comprises a body 22 containing a pen head 28 whose operation is described in more detail hereinbelow. Mounted on body 22 is a slideable switch 26, which activates or deactivates pen 20. Pen 20 is most preferably connected to a computer 24 which receives signals generated by head 28 as an operator writes a character with the pen, and decodes the signals into a digital signal corresponding to the character, utilizing a processing unit 25, which is preferably comprised in a computer 24. alternatively, the pen may contain processing unit 25 and a memory in which the digital signals are initially stored while the pen is not connected to the computer; and the signals are later conveyed to the computer when a connection is made therewith. Further alternatively or additionally, the signals may be stored and/or output in the form of a curved line or drawing, corresponding to written characters or foims that would have been generated by the operator had he been using a conventional pen or stylus on a page or tablet. Fig. 2A and Fig. 2B are, respectively, a schematic cross-sectional view and a schematic exploded view showing pen head 28 of Fig. 1, in accordance with a preferred embodiment of the present invention. Pen head 28 acts as a transducer converting lateral movements of the head to electrical signals. Head 28 comprises a lever arm 52 having a substantially spherical section 48. Arm 52 is held in place by an aim holder 30, which mates with section 48, so that arm 52 and holder 30 operate as a ball-and-socket joint. Most preferably, arm holder 30 is constructed from opaque plastic. .An industry-standard battery 34, mounted inside body 22, powers a plurality of lights 38 mounted on holder 30 when the battery is activated by sliding switch 26. Lights 38 are mounted so as to illuminate arm 52. The detailed operation and construction of arm 52 is described hereinbelow. Aim 52 comprises two sections fixedly connected together: an opaque, substantially cylindrical rod 42, including section 48 described above, and a transparent, generally conical light concentrator 54. Most preferably, rod 42 and concentrator 54 are made from plastic, and are cemented together. Concentrator 54 is most preferably constructed from one piece of transparent plastic, such as Plexiglas, so that it has a generally conical form with a substantially hemispherical base 56. Base 56 is coated with a light-reflecting material 44, such as aluminum, and over the light-reflecting material a covering 46, most preferably composed of an elastic material such as rubber, is placed. Rod 42 comprises an optical fiber 40, wherein a first end 57 thereof is most preferably optically cemented to concentrator 54, and wherein a second, opposite end 58 thereof is substantially flush with an end 55 of rod 42. .Arm 52 is constrained by a spring 36 placed between arm 52 and body 22, so that in the absence of an external force on arm 52 the arm remains in a substantially symmetrical, central position relative to holder 30. Head 28 further comprises a two-dimensional photoelectric position sensing device 32, such as an S5991 position sensor produced by Hamamatsu Corporation, of Bridgewater, N.J.. Photoelectric device 32 generates signals responsive to a point of illumination thereon, whereby the signals are indicative of a position of the point of illumination, and the signals are transferred as described above to computer 24 (Fig. 1). Device 32 is positioned within body 22 so that when motion of arm 52 occurs, as described below, end 58 of fiberoptic 40 is close to, but not touching, surface 59. Most preferably, the internal walls of body 22 between array 32 and holder 30 are blackened to minimize light reflections. On activation of switch 26, illumination from lights 38 penetrates concentrator 54, and the illumination is focussed by base 56 onto end 57 of fiberoptic 40. The illumination is transferred by fiberoptic 40 to end 58, which illuminates array 32 at a position corresponding to a "null," central position of arm 52. To operate pen 20, an operator grips body 22 and places the rubber-coated side of base 56 against any convenient fixed surface, and moves the pen body as though he/she were writing a character. The lateral movements of body 22 about the ball joint formed by spherical section 48 and holder 30, relative to base 56 of tip 28, which preferably remains substantially stationary, cause a corresponding series of rotatory deflections of arm 52, and thus a corresponding series of differential positions of rod end 55 from the null position. Device 32 transfers a series of signals corresponding to the series of positions to computer 24, wherein processing unit 25 decodes the series of signals to produce the character written by the operator, by methods known in the art. Most preferably, computer 24 stores and/or outputs the character written as an industry-standard digital signal. It will be understood that contrary to standard writing methods using pens or styli .known in the art, there is substantially no linear movement of pen 20 of the present invention while a character is being written. In preferred embodiments of the present invention, the linear movement is substantially replaced by lateral movement of the pen head about the ball joint described hereinabove. Reference is now made to Fig. 3, which is a schematic pictorial view of a pen 60, in accordance with an alternative preferred embodiment of the present invention. Except as described hereinbelow, pen 60 is constructed and operates substantially as does pen 20, and parts of pen 60 having the same numerals as pen 20 are substantially identical in construction and operation. Pen 60 comprises a pen head 61, which acts as a transducer and generates electrical signals as described hereinbelow as an operator writes a character. Most preferably, the signals are transmitted to processing unit 25 of computer 24, wherein decoding of the signals into a digital signal corresponding to the character is made as described hereinabove. Fig. 4A and Fig. 4B are respectively a schematic cross-sectional view showing pen head 61 of Fig. 3 in a non-operational state and a schematic cross-sectional view showing pen head 61 in an operational state, in accordance with a prefer-ed embodiment of the present invention. Head 61 comprises a plate 68 which generates electrical signals responsive to the position of an end 67 of a rod 66 contacting plate 68. Most preferably, plate 68 operates on the principle of capacitance measurement, as is .known in the art. Alternatively, plate 68 operates on the principle of pressure measurement, as is .known in the art. Rod 66 is comprised in a male section 64 of a lever arm 70. Section 64 further comprises a cylinder 63 and a hemispherical writing tip 78, such that rod 66, cylinder 63, and tip 78 are fixedly connected together. Preferably, section 64, including rod 66, cylinder 63, and hemisphere 78, is constructed as a single unit from a metal such as stainless steel. Most preferably, hemisphere 78 is coated with an elastic coating such as rubber. Lever arm 70 further comprises a female section 62 which slideably receives male section 64. Preferably, section 62 and section 64 are held in position relative to each other by a spring 37 fixedly attached to both sections. Section 62 comprises a tube 72, a substantially spherical section 74, and a generally conical section 76, fixedly connected together and having a central hole which receives male section 64. Most preferably, female section 62 is formed in one piece from plastic. .Arm 70, comprising female section 62 and male section 64, is rotatably held in position by arm holder 30, substantially as described above for pen 20 (Fig. 2 A and Fig. 2B). In the absence of pressure on hemispherical writing tip 78, end 67 of rod 66 does not contact plate 68. In the operational mode of pen 60 (Fig. 4B), hemispherical writing tip 78 is brought into contact with and pressed lightly against any convenient surface 71, so that spring 37 is compressed and so that end 67 contacts plate 68, thereby generating a signal which most preferably is used by processing unit 25 as an initialization signal. The pen can be lifted and replaced against surface 21 to provide repeated initialization signals, to signify, for example, the completion of a written character. Signals generated by plate 68, responsive to position changes of end 67 as a character is being written by an operator, are transferred to processing unit 25 of computer 24. The conversion of the signals to a digital character corresponding to the character written by the operator is substantially as described above for pen 20. Reference is now made to Fig. 5, which is an external schematic view of a pen 80, in accordance with a preferred embodiment of the present invention. Most preferably, pen 80 has similar dimensions to those of pen 20 described hereinabove. Pen 80 comprises a body 86 containing a pen head 90 which acts as a transducer and whose operation is described in more detail hereinbelow. Pen head 90 comprises a spring 100, whose function is described below. Mounted on body 86, most preferably as an integral part of the body, is a display 84. Most preferably, display 84 is a liquid crystal linear display capable of displaying a series of characters. Within body 86, a processing unit 108 receives signals generated by head 90 as an operator writes a character with the pen. Processing unit 108 translates the signals into a digital signal corresponding to the character, and displays the character on display 84. As the operator writes subsequent characters, display 84 shows the sequence of characters written by the operator. Within body 86, pen 80 further comprises a memory 110, preferably a non- volatile memory, which is utilized by processing unit 108 to store the sequence of characters written by the operator, and which may be accessed by computer 24 via a connector 112. Mounted on body 86 is a slideable switch 82, which is able to activate the recall of the sequence of characters, and display the sequence on display 84. Fig. 6A and Fig. 6B are schematic cross-sectional and exploded views, respectively, of pen 80, in accordance with a preferred embodiment of the present invention. The cross- sectional view is taken along a line VIA - VIA in Fig. 5. Pen 80 comprises a battery 104 which powers a printed circuit board 92. Board 92 comprises processing unit 108 and memory 110, and drives display 84. Board 92 receives signals from a circular pressure measuring disc 94, which is comprised in head 90 and is fixedly connected to body 86 and whose function is described in more detail hereinbelow. Fig. 6C is a schematic cross-sectional view of disc 94, taken along a line VIC - VIC in Fig. 6B, in accordance with a preferred embodiment of the present invention. Disc 94 comprises a plurality, preferably four, of pressure measuring transducers 106, fixedly positioned in a ring 93 which has a central hole 95. Head 90 (Fig. 6A and Fig. 6B) further comprises a first ring 97 and a second ring 98, which are held apart by a spring 100, so that ring 98 presses against measuring disc 94. A writing head 96, comprising a substantially hemispherical section 102, is fixedly connected to a far end of a rod 103. A near end of rod 103 passes through hole 95 in disc 94 and has an enlarged end 105, so that rod 103 is rotatably held in place against disc 94 by the compression of spring 100. Operation of pen 80 is initiated by placing section 102 against any convenient fixed surface, whereupon a "null" signal from disc 94 is sent to processing unit 108. To begin writing a character, a series of lateral forces are exerted on body 86 to write the character. The series of lateral forces cause rod 103 to rotate about hole 95, and thereby cause spring 100 to exert a corresponding series of forces on ring 98 and thus on pressure measuring disc 94, which accordingly produces a series of signals corresponding to the series of lateral forces. The signals are decoded by processing unit 108, using the null signal as a reference, to give a digital signal corresponding to the character written. Most preferably, unit 108 utilizes handwriting- recognition software .known in the art and stored in memory 110. Processing unit shows the written character on display 84, and also stores the character in memory 110 from where it may be transferred to an external unit, for example a word-processing unit, via connection 112. If desired, pen 80 is able to write, display, and store a sequence of characters utilizing memory 110, and this sequence may be transferred from memory 110 as described above. Reference is now made to Fig. 7, which is an external schematic view of an electronic pen 120, in accordance with an alternative preferred embodiment of the present invention. Except as described hereinbelow, pen 120 is constructed and operates substantially as does pen 80, so that parts of pen 120 having the same numerals as pen 80 are substantially identical in construction and operation. Pen 120 comprises a head 122 wherein movement of the head is detected and transmitted to board 92 which then decodes the movement to generate a digital character as described above. Fig. 8 A is a schematic cross-sectional view of pen 120, and Fig. 8B is an exploded view of head 122 of the pen, in accordance with a preferred embodiment of the present invention. Head 122 comprises a photoelectric device 124, preferably an array of photodiodes, which senses a two-dimensional position of a beam generated by a laser diode 134. Diode 134 is fixedly mounted onto a near end 132 of a rod 128. Rod 128 comprises a substantially spherical section 130, which mates with a housing 126 fixedly mounted to body 86, so that rod 128 rotatably moves in housing 126. During operation of pen 120, an operator positions hemispherical section 102 against any convenient surface, and writes a character by exerting a sequence of lateral forces on the pen and moving body 86 as described above. The lateral forces and movement cause a corresponding sequence of rotations of rod 128 in housing 126, which vary the position at which the beam from laser diode 134 impinges on photoelectric device 124. A sequence of signals from device 124, responsive to the sequence of positions of the beam, are generated by the device and transmitted to board 92, wherein the signals are preferably decoded to a digital signal corresponding the character written by the operator, as described hereinabove. Reference is now made to Fig. which is an external schematic view of a pen 150, in accordance with an alternative preferred embodiment of the present invention. Except as described hereinbelow, pen 150 is constructed and operates substantially as does pen 120 (Figs. 7, 8A and 8B), so that parts of pen 150 having the same numerals as pen 120 are generally identical in construction and operation. Pen 150 comprises a head 152 wherein movement of the head is detected and transmitted to board 92, which then translates the movement into a digital character as described above. Fig. 9B is a schematic cross-sectional view of pen 150, in accordance with a preferred embodiment of the present invention. Head 152 comprises a Hall detector 154, as is known in the art, which is fixedly connected to end 132 of rod 128. Detector 154 senses a magnetic field generated by a coil 156 fixedly connected to body 86 of pen 150. alternatively, coil 156 may be replaced by a permanent magnet. Most preferably, coil 156 generates a non-symmetrical magnetic field in a region 158, for example by fixedly positioning a piece of ferromagnetic material 160 in or adjacent to the region, so that magnetic field measurements made by detector 154 can be translated into a unique two-dimensional position of the detector. Signals from Hall detector 154 are transferred to board 92, wherein a determination of the position of the detector is made. During operation of pen 150, an operator positions hemispherical section 102 against any convenient surface, and writes a character by exerting a sequence of lateral forces on the pen as described above. The sequence of lateral forces causes a corresponding sequence of rotations of rod 128 in housing 126, and hence causes a corresponding sequence of positions of Hall detector 154. A sequence of signals from the detector, responsive to the sequence of positions, are transmitted to board 92, wherein the signals are decoded into a digital signal corresponding the character written by the operator, as described hereinabove. Fig. 10A is a schematic cross-sectional view of a pen 200, in accordance with a preferred embodiment of the present invention. Except as described hereinbelow, pen 200 is constructed and operates substantially as does pen 80 (Figs. 5, 6A and 6B), so that parts of pen 200 having the same numerals as pen 80 are generally identical in construction and operation. Pen 200 comprises a pen head 230, which acts as a transducer and generates electrical signals as described hereinbelow, as an operator writes a character. Fig. 10B is an exploded view of pen head 230, in accordance with a preferred embodiment of the present invention. Pen head 230 comprises a lever arm 220 which is rotatably held by a spherical opening 218, in a near end of arm 220, mating with a substantially spherical section 210 of a generally cylindrically-shaped arm holder 216. A far end 204 of lever arm 202 is generally spherically shaped, and is placed against any convenient surface when an operator of pen 200 desires to write with the pen. A disc 206 is fixedly attached to a rim 208 of arm 220, and arm 220 and disc 206 are held in a substantially symmetrical position by a spring 202 acting between disc 206 and a lip 224 of body 86. Disc 206 is most preferably constructed from ferromagnetic material. Arm holder 216 further comprises two linear optical encoder assemblies 232 and 234, as are .known in the art, for example optical encoders HEDR 8100, produced by Hewlett- Packard Inc., of Palo ^to, California. The linear optical encoder assemblies are mounted so that respective graticules 212 and 214 (shown in Fig. 10D) of the assemblies slide in grooves on the outside of holder 216. The grooves are most preferably parallel to a general axis of symmetry 240 of pen 200, and are positioned so that their azimuthal separation is substantially equal to 90°, measured about axis 240. Most preferably, graticules 212 and 214 have respective magnets 226 and 228 fixedly attached to the end of the sliders close to arm 220, so that they are magnetically held in place by disc 206. Reference is now made to Fig. IOC, which schematically shows pen head 230 during the act of writing, and to Fig. 10D, which is a schematic cross-sectional view taken along line XD - .XD of Fig. IOC. End 204 of arm 220 has been positioned against a surface S, and pen 200 has been moved generally vertically down, so that arm 220 tilts upwards. As arm 226 tilts upwards, disc 206 rotates in a clockwise direction, pushing magnet 226 and associated graticule 212 to the right. It will be apparent that vertical motion of pen 200 generates a corresponding vertical rotation (about a horizontal axis at right angles to axis 240) of arm 220, and a linear movement of graticule 212. It will also be apparent that vertical motion of pen 200 causes substantially no motion of graticule 214 (Fig. 10B). Similarly, horizontal motion of pen 200 generates a corresponding horizontal rotation (about a vertical axis at right angles to axis 240) of arm 220, and a linear motion of magnet 228 and associated graticule 214, with substantially no motion of graticule 212. Thus for any given movement of pen 200, the vertical component of the movement will correspond to motion of graticule 212, and the horizontal component of the movement will correspond to motion of graticule 214. As is known in the art, linear motion of graticule 212 is optically encoded into a digital electrical signal by an emitter/receiver 222, against which graticule 212 moves. Similarly, linear motion of graticule 214 is encoded into a digital signal by a corresponding emitter/receiver 242. Emitter/receiver 222 and emitter/receiver 242 comprise respective printed circuit boards, which are mounted on respective surfaces 250 and 252 cut into holder 216. The digital signals are transmitted to board 92, wherein the signals are decoded into a digital signal corresponding to the character written by the operator, as described hereinabove. It will be appreciated that other combinations of specific elements of the preferred embodiments described hereinabove may be used to produce other pens using the principles of the present invention, including the use of a substantially stationary pen head and a flexible joint between the pen head and body. All such combinations, and combinations utilizing methods for lateral force and motion detection not specifically described hereinabove, are to be considered as within the scope of the present invention. Moreover, it will be appreciated that the principles of the present invention may similarly be used in producing computer pointing devices. It will thus be understood that the preferred embodiments described above are cited by way of example, and the full scope of the invention is limited only by the claims.

Claims: CLAIMS I . An electronic pen for generating a signal corresponding to handwriting of an operator, comprising: a pen body, which is grasped and manipulated by the operator in a manner similar to that which the operator would use to write on a page; a pen head, coupled to the body, which is brought into contact with a surface and is held generally stationary in contact therewith while the operator manipulates the pen body; and a transducer coupled to the pen body so as to generate the signal responsive to the manipulation thereof. 2. A pen according to claim 1, and comprising a flexible joint, which couples the head to the body and flexes responsive to the manipulation of the body. 3. A pen according to claim 2, wherein the transducer generates the signal responsive to flexure of the joint. 4. A pen according to claim 2, wherein the joint comprises a lever arm fixed to the pen head, which arm pivots within the joint responsive to the manipulation. 5. A pen according to claim 4, wherein the joint comprises a ball joint which rotatably holds the arm. 6. A pen according to claim 1, wherein operation of the pen is initiated by contact of the pen head with the surface. 7. A pen according to claim 1, and comprising a processing unit which decodes the signal to form a digital character. 8. A pen according to claim 7, wherein the processing unit is comprised in the pen body. 9. A pen according to claim 7, and comprising a memory which stores predetermined instructions for the processing unit to decode the signal. 10. A pen according to claim 9, wherein the memory stores the decoded signal. I I . A pen according to claim 1, wherein the pen body comprises a display which shows a character responsive to the handwriting. 12. A pen according to claim 1, wherein the manipulation is measured relative to an initial null position generated at an initiation of operation of the pen. 13. A pen according to claim 1, wherein the transducer comprises a photoelectric position sensing device. 14. A pen according to claim 1, wherein the transducer comprises a pressure sensing device. 15. A pen according to claim 1, wherein the transducer comprises a capacitance sensing device. 16. A pen according to claim 1, wherein the transducer comprises a magnetic field sensing device. 17. A pen according to claim 1, wherein the transducer comprises an optical encoder. 18. A pen according to claim 17, wherein the encoder comprises a linear encoder. 19. A method for generating an electronic representation corresponding to a handwritten character, comprising: providing an elongate instrument, having a body with a transducer coupled to sense manipulation thereof; bringing an end of the instrument into contact with a point on a surface; and manipulating the body of the instrument in a manner corresponding to writing the character, while maintaining the end of the instrument in contact with the point on the surface, so that the transducer generates signals responsive to the manipulation. 20. A method according to claim 19, wherein manipulating the body comprises flexing a joint in the instrument. 21. A method according to claim 20, wherein flexing the joint comprises flexing the joint about the point on the surface. 22. A method according to claim 19, and comprising decoding the signal to form a digital character.

Inventors: SHAPIRA RAN, SHAPIRA, RAN
Applicants: SHAPIRA RAN, SHAPIRA, RAN
Application year: 1998
Main classification: G08C21
IPC codes: G06F3, G08C21, G09G5