CA1113579A - Electrographic apparatus - Google Patents
Electrographic apparatusInfo
- Publication number
- CA1113579A CA1113579A CA328,475A CA328475A CA1113579A CA 1113579 A CA1113579 A CA 1113579A CA 328475 A CA328475 A CA 328475A CA 1113579 A CA1113579 A CA 1113579A
- Authority
- CA
- Canada
- Prior art keywords
- flexible membrane
- frame member
- base member
- flexible
- sides
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
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
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/045—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/004—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring coordinates of points
Abstract
A B S T R A C T
Electrographic apparatus includes a transducer pad having a flexible membrane mounted over a base member with facing surfaces of the membrane and base member being electrically conductive and having electrical voltages applied thereto whereby to provide electrical signals representing the coordinates of a location at which pressure is applied to the flexible membrane locally by a pen or stylus, wherein in order to maintain an appropriate tension in the flexible membrane, the membrane is attached to and mounted on an outwardly tensioned rectangular frame member.
The frame member may comprise separate frame elements and spring members forcing the elements away from one another.
Alternatively, the frame member may be resilient and be inwardly compressed during the attaching thereto of the flexible membrane whereby the inherent resilience of the frame member subsequently tensions the flexible membrane.
Electrographic apparatus includes a transducer pad having a flexible membrane mounted over a base member with facing surfaces of the membrane and base member being electrically conductive and having electrical voltages applied thereto whereby to provide electrical signals representing the coordinates of a location at which pressure is applied to the flexible membrane locally by a pen or stylus, wherein in order to maintain an appropriate tension in the flexible membrane, the membrane is attached to and mounted on an outwardly tensioned rectangular frame member.
The frame member may comprise separate frame elements and spring members forcing the elements away from one another.
Alternatively, the frame member may be resilient and be inwardly compressed during the attaching thereto of the flexible membrane whereby the inherent resilience of the frame member subsequently tensions the flexible membrane.
Description
S~
This invention is concerned with transducer pads for electrographic apparatus arranged to provide electrical signals representing the co-ordinates of a location at which pressure is applied locally to a writing surface of the pad by the action, for example, of a stylus or writing implement.
Such apparatus can be arranged to provide substantially continuous electrical monitoring of the position of a writing implement during writing or drawing on a document resting on the writing surface of a transducer pad and the resulting electrical signals can be used for example to provide simultaneous reproduction of the writing or drawing at a distance.
A known type of transducer device compris~s a flexible membrane mounted parallel to a fixed base, the opposing surfaces of the membrane and the base being each coated with a resistive film. Excitation voltages are applied to the resistive films at an angle to one another, usually 90 degrees, through conducting strips so that when pressure is applied to the membrane by a stylus or the like, two analog electrical voltages related unambiguously to the position of the stylus are obtained.
An object of this invention is to provide an improved construction of transducer pads of this type, particularly as regards the tensioning of the flexible membrane.
From one aspect, the invention provides a transducer pad for electrographic apparatus comprising a flexible membrane having a resistive surface with its edges secured to a rectangular frame, the opposite sides of which are pressed outwardly away from one another by resilient means.
:
..
~, S`ft'~j From another aspect, the invention provides a transducer pad for electrographic apparatus in which the flexible resistive membrane is secured along its edges to the members of a rectangular frame and is tensioned by resilient means forcing opposite members of the frame outwardly away from one another.
The frame may be a complete frame of resilient material which is pre-stressed before the membrane is secured to it, so that it expands thereafter to provide the resilient means tensioning the membrane.
Alternatively, the frame may comprise four separate bars to which the membrane is secured and which are forced apart from one another by spring means to tension the membrane. -The membrane may be secured to the frame by adhesive which should be compatible as to its characteristics with the material of the membrane.
When a complete frame is used with the membrane, the side members of the frame may increase in width from each end to the centre so that a substantially uniform stress is applied to the membrane. The width of the material at the corners of the frame may be reduced to increase the resilience of the frame.
Membranes forming the top and bottom surfaces respectively may be secured as by glueing to a frame, of which the sides are forced outwardly so that an easily replaceable ~nit for the tran~sducer is provided. The side members of the frame may taper outwardly in cross-section so that the edges of the two membranes may be brought together and secured by adhesive.
,, :. ~:
. -: ., . . - :
- -:. , ' -Other parts of the invention are embodied in the preferred forms which will now be described in some detail, with reference to the accompanying drawings, in which:-Figure 1 is a perspective view partly in section of5 one form of transducer according to the invention, Figure 2 is a plan view of a frame used in the form of Figure l;
Figure 3 is a perspective view of a unit embodying two resistive surfaces;
Figure 4 is a section on the line IV-IV of Figure 3 to an enlarged scale;
Figure 5 is a perspective view of another form of transducer according to the invention;
Figure 6 is a perspective view of another form;
Figure 7 is a perspective view of yet another form;
and Figure 8 is an underneath view of the form of Figure 7.
As shown in Figure 1, a transducer pad comprises a base 1 having an upstanding rectangular nib 2 parallel to its four edges. The top surface of the base 1 is slightly concave and carries a resistive surface 3 (the Y surface) which, as shown, comprises a membrane secured to the base by screws. A membrane 4 having a resistive under surface (the X surface) is stretched across the nib 2 so as to be spaced from the resistive surface 3. Means (not shown) are provided to supply excitation voltages to the X and Y
surfaces at right angles to one another so that when the two surfaces are brought into contact at any point, two analog electrical voltages are produced related unambiguously to the location of that point.
: ' ' ' ',. :
. . : , .~ , .
~13~ ~
The membrane 4 is secured by adhesive to a resilientframe 5. Before application of the membrane, the frame 5 is compressed inwardly from each side as indicated by the - arrows in Figure 2. The membrane 4 is then glued to the frame by means of a compatible adhesive and the frame and membrane held between two plates until the adhesive is set.
The surfaces of these plates are coated with polytetrafluoroethylene to prevent sticking of the plates to the membrane. A suitable adhesive is a modifed polyester resin sold by G.T. Sheldahl Limited, Eastern Road, Bracknell, under the designation "Schjel-bond adhesive".
When the adhesive has set, the plates are removed and the compressive stress on the frame is removed. The frame then expands and exerts tensile forces on the membrane to produce a uniformly taut surface.
The sides of the frame are shaped to provide for uniform stress on the membrane. The width of the frame sides increases inwardly from each end to the centre in a manner which can be determined by the conventional loaded-beam theory. To increase the resilience of the frame, the corners may be recessed to reduce the width of material there.
The frame 5 is placed on the base 1 outside the nibs 2 and is secured by a cover 6. The membrane 4 presses on the rectangular nib 2 which determines the clearance between the X and Y surfaces. A slight difference in height between the underside of the cover 6 and the tip of the nib 2 provides additional tension to the diaphragm and ensures its flatness.
In the form shown in Figure 3, two membranes 8, g . . ~ . ~ - - .
~L3~
having resistive surfaces are glued to opposite sides of the rectangular spring frame 10 with their resistive surfaces opposite to one another. Silver connection strips 11, 12 are provided on opposite sides of membranes 8, 9 respectively. In manufacture, the spring frame 10 is stressed before the membranes are attached so that when released the frame expands and tautens the two membranes.
The cross-section of the frame 10 is such as to provide the desired separation of the X and Y surfaces while, at the same time, being of low torsional rigidity and strength for low, even tensioning of the surfaces. The cross-section of the frame is preferably trapezoidal, tapering towards the outside, so that the edges of the membranes can be brought close to one another for glueing together.
In the forms of the invention shown in Figures 5, 6 and 7, a frame comprising four separated bars is used and spring means are provided to expand the frame and stretch the membrane in two directions at right angles.
In Figure 5, the membrane 4 is secured by adhesive along its edges to four separate bars 14 which together form a rectangular frame. Within the bars 14 are based springs 15. The membrane is placed on the base 1 with the bars outside the nib 2 and the springs 15 bear against the sides of the nib exerting a force tending to force opposite bars apart and so tension the membrane 4. The bars 14 are retained in this extended position by screws 16 securing them to the base 1.
In the form shown in Figure 6, the membrane 4 is secured as in Figure 5 to four bars 14. In the base 1, on each of the four sides thereof, plungers 17 pressed .
outwardly by springs 18 are provided. These plungers are each formed with a transverse bore and a peg 19 having a tapered end passes through a tapered hole in the bar 14 into this bore. The springs 18 force the plungers 17 and the pegs 19 outwardly thereby forcing opposite bars 14 apart and tensioning the membrane 4.
In the form shown in Figure 7, the bars 14 to which the membrane 4 is secured, are formed with downwardly projecting pegs 20 which pass through extended slots 21 in a sheet metal base 22 which supports the lower resistive surface 3. Upstanding projectlons 23 are provided on the metal sheet 22 between the slots 21 and wire springs 24 engage opposite sides of these projections 23 and of the pegs 20, so as to force the pegs on opposite sides away from one another.
It will be understood that the invention is not restricted to the details of the preferred forms described by way of example, which may be modified without departure from the scope of the accompanying claims.
. ~ -
This invention is concerned with transducer pads for electrographic apparatus arranged to provide electrical signals representing the co-ordinates of a location at which pressure is applied locally to a writing surface of the pad by the action, for example, of a stylus or writing implement.
Such apparatus can be arranged to provide substantially continuous electrical monitoring of the position of a writing implement during writing or drawing on a document resting on the writing surface of a transducer pad and the resulting electrical signals can be used for example to provide simultaneous reproduction of the writing or drawing at a distance.
A known type of transducer device compris~s a flexible membrane mounted parallel to a fixed base, the opposing surfaces of the membrane and the base being each coated with a resistive film. Excitation voltages are applied to the resistive films at an angle to one another, usually 90 degrees, through conducting strips so that when pressure is applied to the membrane by a stylus or the like, two analog electrical voltages related unambiguously to the position of the stylus are obtained.
An object of this invention is to provide an improved construction of transducer pads of this type, particularly as regards the tensioning of the flexible membrane.
From one aspect, the invention provides a transducer pad for electrographic apparatus comprising a flexible membrane having a resistive surface with its edges secured to a rectangular frame, the opposite sides of which are pressed outwardly away from one another by resilient means.
:
..
~, S`ft'~j From another aspect, the invention provides a transducer pad for electrographic apparatus in which the flexible resistive membrane is secured along its edges to the members of a rectangular frame and is tensioned by resilient means forcing opposite members of the frame outwardly away from one another.
The frame may be a complete frame of resilient material which is pre-stressed before the membrane is secured to it, so that it expands thereafter to provide the resilient means tensioning the membrane.
Alternatively, the frame may comprise four separate bars to which the membrane is secured and which are forced apart from one another by spring means to tension the membrane. -The membrane may be secured to the frame by adhesive which should be compatible as to its characteristics with the material of the membrane.
When a complete frame is used with the membrane, the side members of the frame may increase in width from each end to the centre so that a substantially uniform stress is applied to the membrane. The width of the material at the corners of the frame may be reduced to increase the resilience of the frame.
Membranes forming the top and bottom surfaces respectively may be secured as by glueing to a frame, of which the sides are forced outwardly so that an easily replaceable ~nit for the tran~sducer is provided. The side members of the frame may taper outwardly in cross-section so that the edges of the two membranes may be brought together and secured by adhesive.
,, :. ~:
. -: ., . . - :
- -:. , ' -Other parts of the invention are embodied in the preferred forms which will now be described in some detail, with reference to the accompanying drawings, in which:-Figure 1 is a perspective view partly in section of5 one form of transducer according to the invention, Figure 2 is a plan view of a frame used in the form of Figure l;
Figure 3 is a perspective view of a unit embodying two resistive surfaces;
Figure 4 is a section on the line IV-IV of Figure 3 to an enlarged scale;
Figure 5 is a perspective view of another form of transducer according to the invention;
Figure 6 is a perspective view of another form;
Figure 7 is a perspective view of yet another form;
and Figure 8 is an underneath view of the form of Figure 7.
As shown in Figure 1, a transducer pad comprises a base 1 having an upstanding rectangular nib 2 parallel to its four edges. The top surface of the base 1 is slightly concave and carries a resistive surface 3 (the Y surface) which, as shown, comprises a membrane secured to the base by screws. A membrane 4 having a resistive under surface (the X surface) is stretched across the nib 2 so as to be spaced from the resistive surface 3. Means (not shown) are provided to supply excitation voltages to the X and Y
surfaces at right angles to one another so that when the two surfaces are brought into contact at any point, two analog electrical voltages are produced related unambiguously to the location of that point.
: ' ' ' ',. :
. . : , .~ , .
~13~ ~
The membrane 4 is secured by adhesive to a resilientframe 5. Before application of the membrane, the frame 5 is compressed inwardly from each side as indicated by the - arrows in Figure 2. The membrane 4 is then glued to the frame by means of a compatible adhesive and the frame and membrane held between two plates until the adhesive is set.
The surfaces of these plates are coated with polytetrafluoroethylene to prevent sticking of the plates to the membrane. A suitable adhesive is a modifed polyester resin sold by G.T. Sheldahl Limited, Eastern Road, Bracknell, under the designation "Schjel-bond adhesive".
When the adhesive has set, the plates are removed and the compressive stress on the frame is removed. The frame then expands and exerts tensile forces on the membrane to produce a uniformly taut surface.
The sides of the frame are shaped to provide for uniform stress on the membrane. The width of the frame sides increases inwardly from each end to the centre in a manner which can be determined by the conventional loaded-beam theory. To increase the resilience of the frame, the corners may be recessed to reduce the width of material there.
The frame 5 is placed on the base 1 outside the nibs 2 and is secured by a cover 6. The membrane 4 presses on the rectangular nib 2 which determines the clearance between the X and Y surfaces. A slight difference in height between the underside of the cover 6 and the tip of the nib 2 provides additional tension to the diaphragm and ensures its flatness.
In the form shown in Figure 3, two membranes 8, g . . ~ . ~ - - .
~L3~
having resistive surfaces are glued to opposite sides of the rectangular spring frame 10 with their resistive surfaces opposite to one another. Silver connection strips 11, 12 are provided on opposite sides of membranes 8, 9 respectively. In manufacture, the spring frame 10 is stressed before the membranes are attached so that when released the frame expands and tautens the two membranes.
The cross-section of the frame 10 is such as to provide the desired separation of the X and Y surfaces while, at the same time, being of low torsional rigidity and strength for low, even tensioning of the surfaces. The cross-section of the frame is preferably trapezoidal, tapering towards the outside, so that the edges of the membranes can be brought close to one another for glueing together.
In the forms of the invention shown in Figures 5, 6 and 7, a frame comprising four separated bars is used and spring means are provided to expand the frame and stretch the membrane in two directions at right angles.
In Figure 5, the membrane 4 is secured by adhesive along its edges to four separate bars 14 which together form a rectangular frame. Within the bars 14 are based springs 15. The membrane is placed on the base 1 with the bars outside the nib 2 and the springs 15 bear against the sides of the nib exerting a force tending to force opposite bars apart and so tension the membrane 4. The bars 14 are retained in this extended position by screws 16 securing them to the base 1.
In the form shown in Figure 6, the membrane 4 is secured as in Figure 5 to four bars 14. In the base 1, on each of the four sides thereof, plungers 17 pressed .
outwardly by springs 18 are provided. These plungers are each formed with a transverse bore and a peg 19 having a tapered end passes through a tapered hole in the bar 14 into this bore. The springs 18 force the plungers 17 and the pegs 19 outwardly thereby forcing opposite bars 14 apart and tensioning the membrane 4.
In the form shown in Figure 7, the bars 14 to which the membrane 4 is secured, are formed with downwardly projecting pegs 20 which pass through extended slots 21 in a sheet metal base 22 which supports the lower resistive surface 3. Upstanding projectlons 23 are provided on the metal sheet 22 between the slots 21 and wire springs 24 engage opposite sides of these projections 23 and of the pegs 20, so as to force the pegs on opposite sides away from one another.
It will be understood that the invention is not restricted to the details of the preferred forms described by way of example, which may be modified without departure from the scope of the accompanying claims.
. ~ -
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In an electrographic apparatus of the type compris-ing a transducer pad for providing electrical signals represent-ing the coordinates of a location at which pressure is applied locally to a writing surface of the pad by a pen or stylus, the transducer pad including a base member having a conductive sur-face to which a voltage is applied, the improvement comprising a flexible frame member adapted to be mounted on said base member, a flexible membrane securely mounted on said flexible frame member, said flexible membrane being spaced from said base member and having a conductive surface adapted to make electrical con-tact with the conductive surface of the base member when a pen or stylus is applied to said flexible membrane, and means for applying voltage to the said conductive surface of said flexible membrane, said flexible frame member comprising four sides each of which is prestressed inwardly during the securing of said flexible membrane thereto and each of which increases in cross section from its ends to its center so as to cause said four sides to produce uniform tensile force in said flexible membrane secured thereto.
2. Electrographic apparatus according to claim 1, wherein the sides of said frame member are recessed at their ends.
3. In an electrographic apparatus of the type com-prising a transducer pad for providing electrical signals repre-senting the coordinates of a locate at which pressure is applied locally to a writing surface of the pad by a pen or stylus, the pad including a base member, the improvement comprising a flex-ible frame member adapted to be mounted on said base member, a first flexible membrane secured to said flexible frame member, a second flexible membrane secured to said first flexible frame member in spaced relation to said first flexible membrane said first flexible membrane having a conductive surface adapted to make electrical contact with a conductive surface of said second flexible member when a pen or stylus is applied to said first flexible membrane, and means for applying voltages to the said conductive surfaces of said flexible membranes, said flexible frame member comprising four sides each of which is prestressed inwardly during the securing of said flexible membranes thereto to cause said four sides to produce uniform tensile force on said first and second flexible membranes secured thereto.
4. Electrographic apparatus according to claim 3, in which each of said sides of said frame member is trapezoidal in cross section, said sides being so oriented that the narrower edges of said sides form the outer edges of said frame member.
5. Electrographic apparatus according to claim 1, including rectangular upstanding nib means mounted on said base member around said conductive surface of said base member and bearing against said flexible membrane to urge it away from said conductive surface of said base member.
6. In an electrographic apparatus of the type com-prising a transducer pad for providing electrical signals rep-resenting the coordinates of a locate at which pressure is ap-plied locally to a writing surface of the pad by a pen or stylus, the pad including a base member having a conductive surface to which a voltage is applied, the improvement comprising a frame member adapted to be mounted on said base member, a flexible membrane securely mounted on said frame member, said flexible membrane being spaced from said base member and having a con-ductive surface adapted to make electrical contact with the con-ductive surface of the base member when a pen or stylus is applied to said flexible membrane, and means for applying voltage to said conductive surface of said flexible membrane, said frame member comprising four sides and including spring biasing means arranged to urge opposite ones of said sides apart from one another thereby to tauten said flexible membrane.
7. Electrographic apparatus according to claim 6, wherein said base member includes rectangular upstanding nib means disposed around said conductive surface of said base member and adapted to bear against said flexible membrane to urge it away from said conductive surface of said base member.
8. Electrographic apparatus according to claim 7, in which said spring biasing means is arranged to act against side surfaces of said nib means.
9. Electrographic apparatus according to claim 6, wherein said frame member includes four plungers, one for each side of said frame member, mounted in said base member and mech-anically coupled to respective sides of said frame member by pegs, said plungers being acted upon by said spring biasing means.
10. Electrographic apparatus according to claim 6, wherein said frame member includes a plurality of pegs which are attached respectively toward an end of each of said sides, said pegs extending through the base member, and projections on the base member positioned centrally with respect to each side of said frame member, said spring biasing means comprising four wire springs each fixed between a respective one of said pro-jections and a pair of said pegs.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB23699/78A GB1597547A (en) | 1978-05-30 | 1978-05-30 | Electrographic apparatus |
| GB23699/78 | 1978-05-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1113579A true CA1113579A (en) | 1981-12-01 |
Family
ID=10199851
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA328,475A Expired CA1113579A (en) | 1978-05-30 | 1979-05-28 | Electrographic apparatus |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4289925A (en) |
| EP (1) | EP0005996B1 (en) |
| JP (1) | JPS54156662A (en) |
| AU (1) | AU4751279A (en) |
| CA (1) | CA1113579A (en) |
| DE (1) | DE2961950D1 (en) |
| GB (1) | GB1597547A (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4455450A (en) * | 1981-09-25 | 1984-06-19 | Margolin George D | Digitizing tablet |
| US4570149A (en) * | 1983-03-15 | 1986-02-11 | Koala Technologies Corporation | Simplified touch tablet data device |
| JPS6082334U (en) * | 1983-11-02 | 1985-06-07 | アルプス電気株式会社 | input device |
| FR2634579A1 (en) * | 1988-07-25 | 1990-01-26 | Mcb | Potentiometer operable by a slight mechanical stress |
| FR2643499A2 (en) * | 1988-07-25 | 1990-08-24 | Mcb | POTENTIOMETER CONTROLLABLE BY REDUCED MECHANICAL CONSTRAINT |
| US5711672A (en) * | 1994-07-01 | 1998-01-27 | Tv Interactive Data Corporation | Method for automatically starting execution and ending execution of a process in a host device based on insertion and removal of a storage media into the host device |
| US5624265A (en) * | 1994-07-01 | 1997-04-29 | Tv Interactive Data Corporation | Printed publication remote contol for accessing interactive media |
| US5757304A (en) * | 1996-09-13 | 1998-05-26 | Tv Interactive Data Corporation | Remote control including an integrated circuit die supported by a printed publication and method for forming the remote control |
| WO1998040863A1 (en) | 1997-03-14 | 1998-09-17 | Tv Interactive Data Corporation | A method of detachably attaching an insert to a remote control base and the resulting remote control |
| US5852974A (en) * | 1997-08-29 | 1998-12-29 | Egan Visual Inc. | Internal adjustable tension frame for touch-sensitive boards |
| US6664950B1 (en) * | 1999-11-17 | 2003-12-16 | L-3 Communications | Resistive touch panel using removable, tensioned top layer |
| US7687736B2 (en) * | 2004-04-29 | 2010-03-30 | Smart Technologies Ulc | Tensioned touch panel and method of making same |
| GB2547032B (en) * | 2016-02-05 | 2020-05-20 | Ford Global Tech Llc | A vehicle human interface assembly |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3440522A (en) * | 1967-04-03 | 1969-04-22 | Litton Systems Inc | Conductive plastic overlay for target display |
| US3522664A (en) * | 1967-11-20 | 1970-08-04 | Westinghouse Electric Corp | Interface device and display system |
| US3735023A (en) * | 1972-04-19 | 1973-05-22 | Univ Kentucky Research Found | Sensor package for electrical sensing of plane coordinates and method of preparing the same |
| GB1404460A (en) * | 1972-11-28 | 1975-08-28 | Standard Telephones Cables Ltd | Device for transmitting cursive script or drawi'g over a telephone |
| US3959585A (en) * | 1974-02-01 | 1976-05-25 | Bell Telephone Laboratories, Incorporated | Graphical input terminal |
| US3925610A (en) * | 1974-08-12 | 1975-12-09 | Bell Telephone Labor Inc | Graphic communications tablet |
| GB1554108A (en) * | 1975-08-05 | 1979-10-17 | Quest Automation | Electrographic apparatus and method of producing an electrode surface therefor |
| GB1597375A (en) * | 1977-03-09 | 1981-09-09 | Nat Res Dev | Graphical input apparatus for electrical equipment |
-
1978
- 1978-05-30 GB GB23699/78A patent/GB1597547A/en not_active Expired
-
1979
- 1979-05-28 CA CA328,475A patent/CA1113579A/en not_active Expired
- 1979-05-29 AU AU47512/79A patent/AU4751279A/en not_active Abandoned
- 1979-05-29 US US06/043,595 patent/US4289925A/en not_active Expired - Lifetime
- 1979-05-29 JP JP6573079A patent/JPS54156662A/en active Pending
- 1979-05-30 EP EP79300989A patent/EP0005996B1/en not_active Expired
- 1979-05-30 DE DE7979300989T patent/DE2961950D1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2961950D1 (en) | 1982-03-11 |
| GB1597547A (en) | 1981-09-09 |
| EP0005996B1 (en) | 1982-01-27 |
| US4289925A (en) | 1981-09-15 |
| AU4751279A (en) | 1979-12-06 |
| JPS54156662A (en) | 1979-12-10 |
| EP0005996A1 (en) | 1979-12-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 19981201 |