WO1988005576A1 - Stylus device for input to a computer - Google Patents

Stylus device for input to a computer Download PDF

Info

Publication number
WO1988005576A1
WO1988005576A1 PCT/GB1988/000006 GB8800006W WO8805576A1 WO 1988005576 A1 WO1988005576 A1 WO 1988005576A1 GB 8800006 W GB8800006 W GB 8800006W WO 8805576 A1 WO8805576 A1 WO 8805576A1
Authority
WO
WIPO (PCT)
Prior art keywords
stylus
housing
coils
relative
coil
Prior art date
Application number
PCT/GB1988/000006
Other languages
French (fr)
Inventor
Michael Henry Baker
Original Assignee
Terminal Display Systems Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Terminal Display Systems Limited filed Critical Terminal Display Systems Limited
Publication of WO1988005576A1 publication Critical patent/WO1988005576A1/en

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
    • G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
    • G06F3/03545—Pens or stylus

Definitions

  • a S tylus device for input to a computer.
  • the present invention relates to a stylus device for use with a tablet position sensing apparatus.
  • Apparatus for generating video signals related to the position of the tip of a stylus which is placed .in contact with a touch tablet.
  • the stylus comprises a pen-like body including a switch which is actuated when the stylus tip contacts
  • the stylus also incorporates a pick-up or transmitting coil mounted near its tip which coil is intended to pick up signals from or transmit signals to the touch tablet to enable identification of the portion of the touch tablet against which the
  • ⁇ stylus is pressed.
  • a decoding apparatus is used to generate signals representing a picture element in a video waveform, the position of the picture element corresponding to the position of the stylus tip on
  • Lines can be drawn by pushing the . stylus across the surface of the tablet.
  • the switch of the above described stylus is a simple on/off device and accordingly the pressure with which the stylus is applied to the touch tablet
  • British Patent No. 2 089 625 describes briefly a stylus comprising an integral spring-loaded potentiometer the position of the wiper of which is a function of the pressure applied to the stylus tip. j It is difficult with such an arrangement to achieve a
  • a stylus device for use with a tablet position sensing apparatus, comprising an elongate housing, a stylus projecting from one end of the housing and resiliently supported by the housing such that pressure on the projecting portion of the stylus causes the stylus to move axially relative to the housing, a metallic element mounted to move with the stylus relative to the housing, at least one coil supported by the housing in a predetermined position so as to extend around the metallic element ⁇ uch that electrical characteristics of the coil are dependent upon the position of the metallic element relative to tne housing, and means for supplying an energising current to the coil.
  • the metallic element is fabricated from a ferrous material.
  • the coil arrangement comprises three coils spaced apart axially in the housing such that the ferrous element forms a core around which the cores are disposed, the assembly forming a differential transformer.
  • An A/C current is supplied to the central one of the three coils and the two outer coils are connected so .as to provide an electrical output signal the phase of which is dependent upon the position of the ferrous element relative to the coils.
  • the resilient support for the stylus may be in the form of a compressible element interposed between a support member mounted on the housing and the stylus, the position of the support member relative to the housing being adjustable to adjust the preload pressure on the stylus.
  • a coil 3 is arranged around the stylus adjacent the end of the housing and when energised induces signals around the stylus 2 which are picked up by position sensing circuitry defined by the touch tablet.
  • the position sensing circuitry is conventional and will not therefore be describing in further detail herein.
  • a second coil 4 which is connected in series with the coil 3 and energised by the same alternating current signal induces signals into a pair of pressure sensing coils 5.
  • the coil 4 is placed between the pressure sensing coils 5 and each of the ⁇ e three coils is arranged around a ferrous core 6 which is mounted in a plastics bracket on the end of the stylus 2 so that the ferrous core 6 moves with the stylus 2.
  • a support member in the form of a screw 7 is supported in the housing and a compressible material member 8 is interposed between the screw .7 and the ferrous core 6. Adjustment of the position of the screw 7 relative to the housing makes it possible to adjust the preloading force on the stylus, that preloading force being a function of the compression of the compressible member 8. Adjustment of the position of the screw does not affect the calibration of the stylus device however as the coils 4 and 5 and the ferrous core 6 are not moved.
  • the coils 3 and 4 are connected in series to an alternating current source 9.
  • the -coils 5 are connected and an output is taken from the interconnected terminals of the two coils to provide three inputs to a signal processing circuit 10.
  • the signal processing circuit 10 converts the signals from the coils 5 to a phase characterised signal representative of the position of the ferrous core 6 relative to the coils 5.
  • the phase characterised signal is then compared with the energising signal in comparator 11 which provides a digital output 12.
  • This output is thus a function of the position of the core 6 relative to the coils and this in turn is a function of the pressure applied to the tip of the stylus 2 by the person manipulating the stylus device.
  • This pressure information is then merged with the X,Y coordinate data output stream from the tablet position sensing apparatus and is used in known manner to generate an appropriate video image.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

A stylus device for use with a tablet position sensing apparatus. The device comprises an elongate housing and a stylus projecting from one end of the housing. The stylus is resiliently supported by the housing such that pressure on the projecting portion of the stylus causes the stylus to move axially relative to the housing. A ferrous element is mounted to move with the stylus relative to the housing and one or more coils is supported by the housing in a predetermined position adjacent the ferrous element. The electrical characteristics of the coil are dependent upon the position of the ferrous element relative to the housing. An energising current is supplied to the coil arrangement and a measurement signal is derived which is dependent upon the position of the ferrous element.

Description

A Stylus device for input to a computer.
The present invention relates to a stylus device for use with a tablet position sensing apparatus.
5 Apparatus is known for generating video signals related to the position of the tip of a stylus which is placed .in contact with a touch tablet. Generally the stylus comprises a pen-like body including a switch which is actuated when the stylus tip contacts
<jQ any surface. The stylus also incorporates a pick-up or transmitting coil mounted near its tip which coil is intended to pick up signals from or transmit signals to the touch tablet to enable identification of the portion of the touch tablet against which the
<] stylus is pressed. When the stylus switch is actuated a decoding apparatus is used to generate signals representing a picture element in a video waveform, the position of the picture element corresponding to the position of the stylus tip on
20 the touch tablet. Lines can be drawn by pushing the. stylus across the surface of the tablet.
The switch of the above described stylus is a simple on/off device and accordingly the pressure with which the stylus is applied to the touch tablet
25 does not affect the resultant video image. It is desirable however to provide a stylus which provides a pressure-sensitive output as this more closely corresponds to the effects achieved with conventional artists implements such as pencils or paint brushes.
30 British Patent No. 2 089 625 describes briefly a stylus comprising an integral spring-loaded potentiometer the position of the wiper of which is a function of the pressure applied to the stylus tip. j It is difficult with such an arrangement to achieve a
35 smooth and consistent operation and alternative stylus devices have been proposed as described for example in British Patent Spcification No. 2 148 009. In specification 2 148 009 a stylus is described in which a magnet is positioned in a housing so as to move with the stylus tip, the stylus output being derived by a Hall effect transducer which is sensitive to variations in its distance from the magnet. A movable carrier allows the transducer to be moved relative to the magnet so as to adjust the preload pressure on the stylus and also the calibration of the stylus output but it is not possible to adjust the preload pressure without affecting the calibration of the device.
It is an object of the present invention to provide an improved stylus device for use with a tablet position sensing apparatus.
According to the present invention there is provided a stylus device for use with a tablet position sensing apparatus, comprising an elongate housing, a stylus projecting from one end of the housing and resiliently supported by the housing such that pressure on the projecting portion of the stylus causes the stylus to move axially relative to the housing, a metallic element mounted to move with the stylus relative to the housing, at least one coil supported by the housing in a predetermined position so as to extend around the metallic element εuch that electrical characteristics of the coil are dependent upon the position of the metallic element relative to tne housing, and means for supplying an energising current to the coil.
Preferably the metallic element is fabricated from a ferrous material.
Preferably the coil arrangement comprises three coils spaced apart axially in the housing such that the ferrous element forms a core around which the cores are disposed, the assembly forming a differential transformer. An A/C current is supplied to the central one of the three coils and the two outer coils are connected so .as to provide an electrical output signal the phase of which is dependent upon the position of the ferrous element relative to the coils.
The resilient support for the stylus may be in the form of a compressible element interposed between a support member mounted on the housing and the stylus, the position of the support member relative to the housing being adjustable to adjust the preload pressure on the stylus. An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing, which is a schematic illustration of an embodiment of the invention and associated circuitry. Referring to the drawing, the illustrated stylus device comprises an elongate housing 1 with a non-ferrous non-inking or inking stylus 2. The tip of the stylus projects from the end of the housing and in use is placed in contact with a touch tablet. A coil 3 is arranged around the stylus adjacent the end of the housing and when energised induces signals around the stylus 2 which are picked up by position sensing circuitry defined by the touch tablet. The position sensing circuitry is conventional and will not therefore be describing in further detail herein.
A second coil 4 which is connected in series with the coil 3 and energised by the same alternating current signal induces signals into a pair of pressure sensing coils 5. The coil 4 is placed between the pressure sensing coils 5 and each of theεe three coils is arranged around a ferrous core 6 which is mounted in a plastics bracket on the end of the stylus 2 so that the ferrous core 6 moves with the stylus 2. A support member in the form of a screw 7 is supported in the housing and a compressible material member 8 is interposed between the screw .7 and the ferrous core 6. Adjustment of the position of the screw 7 relative to the housing makes it possible to adjust the preloading force on the stylus, that preloading force being a function of the compression of the compressible member 8. Adjustment of the position of the screw does not affect the calibration of the stylus device however as the coils 4 and 5 and the ferrous core 6 are not moved.
The coils 3 and 4 are connected in series to an alternating current source 9. The -coils 5 are connected and an output is taken from the interconnected terminals of the two coils to provide three inputs to a signal processing circuit 10. Thus the arrangement of the coils 4 and 5 and the ferrous core 6 define a differential transformer the outputs of which change in amplitude and phase as the ferrous core 6 moves relative to the coils. The signal processing circuit 10 converts the signals from the coils 5 to a phase characterised signal representative of the position of the ferrous core 6 relative to the coils 5. The phase characterised signal is then compared with the energising signal in comparator 11 which provides a digital output 12. This output is thus a function of the position of the core 6 relative to the coils and this in turn is a function of the pressure applied to the tip of the stylus 2 by the person manipulating the stylus device. This pressure information is then merged with the X,Y coordinate data output stream from the tablet position sensing apparatus and is used in known manner to generate an appropriate video image.

Claims

CLAIMS:
1. A stylus device for use with a tablet position sensing apparatus, comprising an elongate housing, a stylus projecting frαm one end of the housing and resiliently supported by the housing such that pressure on the projecting portion of the stylus causes the stylus to move axially relative to the housing, a metallic element mounted to move with the stylus relative to the housing, at least one coil supported by the housing in a predetermined position so as to extend around the metallic element such that electrical characteristics of the coil are dependent upon the position of the metallic element relative to the housing, and means for supplying an energising current to the coil.
2. A stylus device according to claim 1, wherein the metallic element is a ferrous element.
3. A stylus device according to claim 1 or 2, comprising a differential transformer in the form of three coils spaced apart axially in the housing such that the metallic element forms a core around which the coils are disposed, the two outer coils being connected in series, and means being provided for supplying an energising current to the other coil, and for transmitting electrical signals from the series connected outer coils.
4. A styluε device according to claim 3, comprising means for monitoring the phase of the electrical signals to detect the position of the metallic element relative to the coils.
5. A stylus device according to claim 1, 2, 3 or 4, comprising a compressible element interposed between a support member mounted on the housing nd the stylus and means for adjusting the position of the support member relative to the housing.
6. A stylus device substantially as hereinbefore described with reference to the accompanying drawing.
PCT/GB1988/000006 1987-01-16 1988-01-06 Stylus device for input to a computer WO1988005576A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8700912 1987-01-16
GB8700912A GB8700912D0 (en) 1987-01-16 1987-01-16 Stylus device

Publications (1)

Publication Number Publication Date
WO1988005576A1 true WO1988005576A1 (en) 1988-07-28

Family

ID=10610751

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1988/000006 WO1988005576A1 (en) 1987-01-16 1988-01-06 Stylus device for input to a computer

Country Status (3)

Country Link
AU (1) AU1081888A (en)
GB (1) GB8700912D0 (en)
WO (1) WO1988005576A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0727756A1 (en) * 1995-02-20 1996-08-21 Wacom Co., Ltd. Pressure sensitive arrangement and stylus pen
EP1215622A2 (en) * 2000-12-13 2002-06-19 Wacom Co., Ltd Pen-shaped coordinate pointing device
GB2475928A (en) * 2009-12-23 2011-06-08 Promethean Ltd An input system including an interactive surface for detecting a contact point and the presence of a response to an excitation signal
EP2650758A1 (en) * 2012-04-11 2013-10-16 BlackBerry Limited Force-sensing stylus pointing device
US20130271431A1 (en) * 2012-04-11 2013-10-17 Research In Motion Limited Force-sensing stylus pointing device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3621720A (en) * 1969-01-27 1971-11-23 Mosler Safe Co Identification system
US4006628A (en) * 1975-11-19 1977-02-08 Ncr Corporation Magnetic induction type transducer means
DE2909847A1 (en) * 1979-03-13 1980-09-25 Siemens Ag Position locator for TV monitor of X-ray system - detects position of contact pin on resistance layer and inputs position data via switch in to data acquisition device
US4227044A (en) * 1979-01-22 1980-10-07 Talos Systems, Inc. Pen status system for digitizer pen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3621720A (en) * 1969-01-27 1971-11-23 Mosler Safe Co Identification system
US4006628A (en) * 1975-11-19 1977-02-08 Ncr Corporation Magnetic induction type transducer means
US4227044A (en) * 1979-01-22 1980-10-07 Talos Systems, Inc. Pen status system for digitizer pen
DE2909847A1 (en) * 1979-03-13 1980-09-25 Siemens Ag Position locator for TV monitor of X-ray system - detects position of contact pin on resistance layer and inputs position data via switch in to data acquisition device

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0727756A1 (en) * 1995-02-20 1996-08-21 Wacom Co., Ltd. Pressure sensitive arrangement and stylus pen
EP1215622A2 (en) * 2000-12-13 2002-06-19 Wacom Co., Ltd Pen-shaped coordinate pointing device
EP1215622A3 (en) * 2000-12-13 2003-12-03 Wacom Co., Ltd Pen-shaped coordinate pointing device
GB2475928A (en) * 2009-12-23 2011-06-08 Promethean Ltd An input system including an interactive surface for detecting a contact point and the presence of a response to an excitation signal
EP2650758A1 (en) * 2012-04-11 2013-10-16 BlackBerry Limited Force-sensing stylus pointing device
US20130271431A1 (en) * 2012-04-11 2013-10-17 Research In Motion Limited Force-sensing stylus pointing device
US8878824B2 (en) 2012-04-11 2014-11-04 Blackberry Limited Force-sensing stylus pointing device

Also Published As

Publication number Publication date
GB8700912D0 (en) 1987-02-18
AU1081888A (en) 1988-08-10

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