WO1988009046A1

WO1988009046A1 - Cursor positioning system for computer readout displays

Info

Publication number: WO1988009046A1
Application number: PCT/US1988/001417
Authority: WO
Inventors: James A. Black, Iii; Michael L. Baumgartner; David L. Colloway; Randall G. Rushe; Randall L. Shepard
Original assignee: Scientific Applications, Inc.
Priority date: 1987-05-04
Filing date: 1988-05-03
Publication date: 1988-11-17

Abstract

Directional pressures exerted on a finger pressure pad (12) mounted on a stationary keyboard, are converted into cursor motion controlling signals through a resistive pressure transducer having a quadrature arrangement (25) of force sensitive resistances (34) which vary as directional functions of the pressures exerted on the pressure pad. The variable resistances are measured through timer circuits (68) of a signal generator (36) to produce the motion controlling signals. Power for operating the signal generator is derived from the computer interface to which the motion controlling signals are fed through a multiplexer (42) together with the other command signals.

Description

CURSOR POSITIONING SYSTEM FOR COMPUTER READOUT DISPLAYS

BACKGROUND OF THE INVENTION

This invention related to a system for controlling the movement of a cursor upon a visual computer display.

Graphic input devices for controlling cursor movement on a visual display is often referred to as a mouse. Such a computer mouse is generally a device used to control positioning of the cursor on a cathode ray display screen in order to enable interaction between the computer and the user by pointing of the cursor at various objects on the screen. One type of mechanical mouse heretofore utilized is movable by rolling on a table top. Cursor movement on the display screen accordingly followed such movement of the mouse. Such devices have been developed to produce commands for operating the computer system heretofore generated by the typing of coded inputs at a keyboard. Thus, the mouse was utilized to cause the cursor to be positioned over selection menus for example, displayed on the computer screen and by depressing of a button on such mouse device. Cursor positioning mice have also been utilized to translate motion of a mechanical designer's hand on the computer screen in computer-aided design applications, as for example, the drawing of lines by^" an architect to describe a building.

All cursor controlling devices or mice include in common, three basic mechanisms. One mechanism is a motion sensor to determine the direction and distance of cursor movement. A second mechanism is a communication interface between the mouse and the computer to convert the movement commands into electrical signals. The third mechanism involves one or more function switches through which the user may for select commands corresponding to the icon under which the cursor is positioned.

Amongst the cursor controlling devices or mice, there are the movable type. One form of movable mouse features a ball housed in a plastic housing contacting two wheels rotatable in planes perpendicular to each other. The wheels will accordingly pick off motion in perpendicular directions as the ball is rolled over a surface. Another type of movable mouse features two wheels mounted on the bottom thereof for direct contact with the surface over which the mouse is moved. A third type of movable mouse utilizes a pair of light emitting diodes and optical detectors to sense motion.

A stationary cursor controlling device or mouse is also available as disclosed, for example, in U.S. Patent No. 4,313,113 to Thornburg. According to the Thornburg patent, the cursor controlling device mounted on a stationary keyboard, includes four directional switches through which directional motion commands are generated. The device disclosed in the Thornburg patent utilizes a through conduction mode of operation requiring a mechanism to break contact between spaced electrodes associated with the directional switches.

It is therefore, an important object of the present invention to provide a cursor controlling mouse device of the stationary type which will facilitate its manipulation for generation of the motion signals from which movement control of the cursor is derived.

A further object of the present invention is to provide a stationary type of cursor control device or mouse not only capable of generating directional command signals but also commands through which velocity and acceleration characteristics of cursor movement may be produced.

Still further objects of the present invention is to provide a stationary type of cursor controlling device from which motion commands are generated without signal discontinuities. Summary of the Invention

In accordance with the present invention, a cursor control device or mouse is provided of the stationary type adapted to be mounted on a command control keyboard with function mode control switches through which command mode selection may be affected. The cursor control device in itself is be in the form of a single omni-directional pressure pad adapted to receive the index finger of the user's hand, such pad being located in space adjacency to the function mode switches in the form of command select buttons adapted to receive three fingers of the hand. The omni- directional pressure pad may be elliptically shaped with a depressed dimple to approximate the shape of the index finger tip allowing the finger to exert pressure in different directions with varying degrees of pressure. A pressure-sensing transducer arrangement underlies the pressure pad in the form of a thin polymer film of resistive ink on a mylar film substrate overlying an arcute segment arrangement of interlinked conductive fingers to form a shunt mode configuration type force sensitive resistance assembly. Thus, according to one embodiment four quadrant force sensitive resistances are established, respectively varying in resistance value in accordance with the direction and magnitude of the applied forces.

The foregoing pressure pad transducer arrangement generates motion signals by connection of the variable resistances to the inputs of mono-stable, multi-vibrators acting as timers. Such timers are connected to a source of power obtained, according to one embodiment, from the control terminals of a commercially known computer interface to which the timers are connected through a voltage regulator to prevent any adverse affect on the supply of power as result of momentary switching of the voltage levels at such terminals in accordance with different operational modes associated therewith, such as idle, timer strobe and switch read-back modes. The timers when triggered into operation, produce data outputs as measurements of the inputs from the variable quadrant resistances. The timer outputs which are directly correlated with or proportional to the resistances or pressures applied to the pressure pad, are fed along separate signal channels to a data multiplexer to which the states of the other function mode switches on the keyboard are fed. The outputs of the data multiplexer are accordingly fed to the computer through its interface for position control of the cursor.

As a result of the foregoing arrangement of the present invention, the control terminals of the computer interface not only provide power for signal generation but also control the operational mode of the cursor control device. Toward that end, the voltage regulator through which the power supply is fed to the cursor control system, is referenced to signal ground and energization of the electronics at twice the voltage levels on each of the control terminals of opposite polarity. Timer circuit operation is thereby achieved for measurement of the force sensitive resistances to provide the motion controlling signals at levels corresponding to the magnitude of the directional pressures exerted. The quadrature arrangement of force sensitive resistances enclose a central null zone underlying the center of the pressure pad. Such quadrature sensor arrangement features overlapping, tappered fingers to eliminate discontinuities at the quadrant boundaries and to equalize the contact surface area in all directions. The level of pressure exerted in different directions as reflected by deformation of the pressure pad will correspondingly vary the resistances to simulate velocity and acceleration characteristics of the directional signals generated for control of the cursor movement.

BRIEF DESCRIPTION OF DRAWING FIGURES

The foregoing objects, features and advantages of the invention, as well as others, will become apparent from the following detailed description given by way of example to be read in connection with the accompanying drawings, wherein:

Figure 1 is a top plan view of a typical cursor controlling keyboard constructed in accordance with one embodiment of. the present invention, associated with a block diagram schematically illustrating the cursor controlling system of which it is a part;

Figure 2 is a section view taken substantially through a plane indicated by Section line 2-2 in Figure 1.

Figure 3 is a section view taken substantially through a plane indicated by Section line 3-3 in Figure 2. Figure 3A is a partial section view taken substantially through a plane indicated by section line 3A-3A in Figure 2.

Figure 4 is a electrical circuit diagram illustrating in greater detail the cursor controlling system schematically depicted in Figure 1. DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring now to the drawings in detail. Figure 1 illustrates a cursor command controlling keyboard generally referred to by reference numeral 10 shown to be rectangular in shape in the illustrated embodiment. As shown in Figures 1 and 2, an omni-directional pressure pad section 12 is mounted adjacent one longitudinal end of the keyboard. The keyboard may feature a rigid plastic base 14 having a non-slip surface layer 16 on the bottom. The base 14 underlies in common the pressure pad section 12 in spaced adjacency to three function switch finger pad sections 18 of generally elongated rectangular shape extending in parallel spaced relationship to each other to accommodate the user's fingers when positioned on the keyboard. The elongated shape of the finger pads 18 allow forward and aft variation in finger position relative to the index finger adapted to be applied to the pressure pad section 12. The width of each elongated finger pad section 18 is dimensioned to comfortably accommodate adult fingers and allow side- to-side orientation therein. The depth of the finger pad sections 18 is enough to provide restraint to maintain proper finger placement. As to the pressure pad section 12, it has a depressed oval dimple formation approximating the shape of the index finger tip and a central projection 13. By rotating the keyboard 10 by 180 either the left hand or the right hand of the opertor may be accommodated. The pressure sensing transducer associated with the pressure pad sections consists of a thin polymer film of electrically resistive ink 27 applied to a mylar film substrate 20 as show in Figures 2 and 3 , mounted on the underside of a flexible plastic layer 22. Underlying the substrate 20 is a printed circuit board 24 with a conductive metal contact arrangement 25 deposited thereon in a configuration shown in detail in Figure 3.

In the particular embodiment shown, the contact arrangement 25 underlies the resistive ink bearing substrate 20 to form a plurality of directionally variable resistances which vary in magnitude as a function of the force applied normal to the layer 20 through the pressure pad section 12 so as to lower the junction resistance between contact surfaces of the contact arrangement 25 on circuit board 24. The resistance values also vary with the geometry of the junction so that areas of applied force of larger contact surface result in lower resistances proportional to the pressures applied. Further, the contact arrangement 25 on board 24 has a shunt mode configuration thereby varying the junction resistance as a function of the spacing between the conductive portions of arrangement 25, which spacing varies in response to deformation of the pressure pad.

As shown in Figure 3 , each of the aforementioned variable resistances is established between a conductive quadrant contact element 26 of arrangement

25 which extends throughout in spaced relationship to conductive finger contact portions 28. The finger portions 28 are tapered from wide ends at quadrant dividing portions 30 interconnecting the fingers of adjacent quadrants. Further, the fingers 28 of one quadrant are interleaved between oppositely tapering fingers extending from the adjacent quadrant opposite the quadrant with which it is interlinked. The contact element 26 extends in a continuous path between the interleaved fingers in each quadrant as shown. The quadrant elements 26 are interconnected by a central ring 29 enclosing null zone 32 which underlies the center of the pressure pad section 12. The quadrant dividing portions 30 are respectively connected to separate terminals 31 on the board 24 as are the respective conductive contact arrangements 33 associated with the finger pad sections 18.

As a result of the pressure-sensor configuration illustrated in Figure 3, the pressure sensing area underlying the pressure pad section 12^* is divided into arcuate segments or quadrants, with each quadrant having its own conductive contacts covered by the oval resistive coating 27 on layer 20 in a shunt mode configuration. The pressures exerted will, therefore, establish four variable resistances corresponding to the quadrants of the configuration 25 shown in Figure 3 which overlap and are interlinked tq avoid signal discontinuities along the quadrant junctions. By tapering the contact fingers 28, the contact area remains relatively constant throughout so that the resistance change in each quadrant is a smooth function of the distance from orthogonal axes. The central zone 32, however, has no contacts so as to also avoid signal discontinuities. The four variable quadrant resistances are respectively referred to by equivalent resistances 34 in Figure 4. Referring now to Figure 1 once again, the outputs of the quadrature sensor associated with the pressure pad section 12, are applied to a motion signal generator 36 which is powered through the computer interface 38 in accordance with one embodiment of the invention. The output of the motion signal generator is applied to a signal transmitting interface 40 to which the function switches 18 are also connected. Thus, the interface 40 transmits the outputs derived from both the pressure sensor arrangement associated with the pressure pad 12 and the pressure sensors associate with the function switches 18 which act as switches to the computer interface 38. The computer interface establishes communication between the keyboard generated signals and a computer 42 with which a visual date readout display 44 is associated. The display having a movable cursor exhibited on its screen under control on the motion signals derived from the pressure pad 12 and fed thereto as generally known in the art. As shown in Figure 4, power for operating the motion signal convertor 36 is derived from the commercially available computer interface 38, such as an EIA Type RS-232 interface. The interface has two modem control terminals 46 and 48 normally haying voltage levels of opposite polarity thereat, such as 9 volts. Such control terminals serve as the power source for the motion signal generator 36 in accordance with the present invention through a half bridge rectifier circuit formed by diodes 50 and 52 respectively connected to the control terminals 46 and

48. Voltage regulation biased with respect to signal ground is provided for by connecting the diodes 50 and 52 through current-limiting resistors 54 and 56 to a pair of zener diodes 58 and 60 interconnected to ground. an output filter capacitor 62 is connected across the regulated voltage lines 64 and 66 to minimize transients during switching of the control terminals 46 and 48. The regulated voltage lines 64 and 66 are at a reduced voltage level of 6 volts for example, suitable as operating potentials for the motion signal generator having four timer circuits to which the four variable resistances 34 are connected for measurement of resistance values thereof.

As shown in Figure 4, the four timer circuits are formed by two dual mono-stable multi-vibrators 68 and 70 connected in parallel to the operating voltage lines 64 and 66 of opposite polarity in such a manner as to power them at twice the voltage levels of each operating voltage line, such as 12 volts. The operating voltage line 64 is also connected in parallel to the resistances 34 for supply of current therethrough to the input terminals of the timer circuits. The timer circuits are triggered into operation by a voltage switching action at the modem control terminal 46 of the interface 38, connected in parallel to the trigger terminals of the timer circuits through resistor 72. When triggered, the output states of the the four timer circuit output states are sampled until time out of the timer circuits to provide time measurements directly correlated with or proportional to the resistance values of the resistances 34 or the pressures applied to the pressure pad 12 as aforementioned.

In order to sample the timer states together with the states of the three function switches 18, the four outputs 74, 76, 78 and 80 of the timer circuits consitituting separate signal channels are connected to input terminals of a data multiplexer 82 in the signal transmitting interface 40. Through the multiplexer 82 the timer state outputs are multiplexed onto the same four computer status terminals 84, 86, 88 and 90 with the output states of the function switches 18 during the different computer operational modes as controlled by the state of the interface control terminals 46 and 48, respectively connected by resistors 72 and 92 to the multiplexed control terminals.

Three pull-up resistors 94 interconnect three input terminals of the data multiplexer 82 in parallel to the regulated voltage line 64 to force high inputs thereon, when the switches 18 are open, said switches being respectively connected to such input terminals. The function switches 18 are connected to the operating voltage line 66 of a polarity opposite to that of the operating voltage line 64 so as to apply a lower level input to the multiplexer when the switches 18 are depressed.

The operating mode of the cursor controlling system is controlled by the computer through the interface 38 by the voltage switching action at its control terminals 46 and 48 as aforementioned. In a timer read-back mode, control terminals 46 and 48 are respectively held at their normal voltage levels of 9 volts of opposite polarity. In a timer strobe mode, the control terminal 46 is switched momentarily to a negative potential of -9 volts for a short duration of five micro-seconds for example, to trigger the timer circuits without adversely affecting the power supply thereto. Upon return to the +9 volt level on the control terminal 46, the timer output states are read back to the computer. A final switch read-back mode occurs when the normally negative voltage control terminal 48 is momentarily switched to a positive potential level of +9 volts for a duration of 10 microseconds, for example, to cause the states of the function switches 18 to be applied by the multiplexer 82 to the computer through the interface 38.

In view of the use of the interface control terminals as the power supply for the timer circuits and the signal transmitting interface 40 by means of the described voltage regulation with respective signal ground, the need for interface drivers is eliminated. The short duration of the voltage switching action at the interface control terminals also does not adversely effect the power supply because of the action of capacitor 62 as hereinbefore described. The switch read-back mode aforementioned operates the cursor controlling system in a polling manner. Polling is affected at a regular rate by incorporating a short routine into the time of date interrupt service software of the computer. Each time such interrupt occurs, such as 18 times per second, the motion controlling signals derived from the pressure pad 12 is read by the triggering action of the control terminals 46 and 48 and data read-back on the status terminals 84, 86, 88 and 90 as aforementioned. The data so generated exhibits a repro »ducible pressure/resistance relationship along the four signal channels of the output lines 74, 76, 78 and 80.

It should be understood that various other changes and modifications may be resorted to without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

CLAIMS :

1. In a system for controlling display of visual data from a computer having an operator controlled keyboard on which command control means is supported and interface means operatively connecting the command control means to the computer for controlling cursor movement on the display, said command control means including a pressure pad mounted on the keyboard, means responsive to the directional pressures exerted on said pad for generating a plurality of directional signals of magnitudes corresponding to said pressures and signal transmitting means for operatively connecting the signal generating means to the computer.

2. The system as defined in claim 1, wherein said signal generating means includes a source of power, a plurality of directional force sensitive resistances connected to said source, and means respectively measuring said resistances for developing said plurality of directional signals in separate signal channels connected to the signal transmitting means.

3. The system as defined in claim 2, wherein said interface means includes control terminals and means connecting the control terminals to the signal generating means for operational control thereof in response to momentary switching of voltage levels at the control terminals, said power source comprising voltage regulating means connected to the control terminals for supply of operating voltage therefrom to the signal generating means and filter means connected to the voltage regulating means for preventing any adverse affect on the supply of operating voltage by said momentary voltage level switching.

4. The system as defined in claim 3, wherein said command control means further includes a plurality of function switches mounted on the keyboard in spaced adjacency to the pressure pad and switch status means for connecting said switches to the signal transmitting means.

5. The system as defined in claim 4, wherein said signal transmitting means includes a data multiplexer having input terminals connected to the signal channels of the signal generating means and the switch status means, and a plurality of output status terminals connected to the computer through the interface means.

6. The system as defined in claim 5, wherein the switch status means includes a plurality of pull-up resistors respectively connecting the source to the input terminals of the multiplexer in parallel with the switches.

7. The system as defined in claim 6, wherein said directional force sensitive resistances respectively extend along arcuate segments in operative underlying relation to the pressure pad, said segments enclosing a null zone centrally underlying the pressure pad.

8. The system as defined in claim 7, wherein each of said directional force sensitive resistances is established between a group of conductive fingers and a contact element spaced therefrom in a shunt mode configuration operatively underlying the pressure pad.

9. The system as defined in claim 8, wherein said conductive fingers from the respective groups overlap and are dimensionally tappered to maintain a substantially constant contact surface area in all directions relative to said null zone.

10. The system as defined in claim l, wherein said command control means further includes a plurality of function switches mounted on the keyboard in spaced adjacency to the pressure pad and switch status means for connecting said switches to the signal transmitting means.

11. The system as defined in claim 10, wherein said signal transmitting means includes a data multiplexer having input terminals connected to the signal channels and the switch status means, and a plurality of output status terminals connected to the computer through the interface means.

12. The system as defined in claim 11, wherein the switch status means includes a plurality of pull-up resistors respectively connecting the source to the input terminals of the multiplexer in parallel with the switches.

13. The system as defined in claim 2, wherein said directional force sensitive resistances respectively extend along arcuate segments in operative underlying relation to the pressure pad, said segments enclosing a null zone centrally underlying the pressure pad.

14. The system as defined in claim 13, wherein each of said directional force sensitive resistances is established between a group of conductive fingers and a contact element spaced therefrom in a shunt mode configuration operatively underlying the pressure pad.

15. The system as defined in claim 14, wherein said conductive fingers from the respective groups overlap and are dimensionally tappered to maintain a substantially constant contact surface area in all directions relative to said null zone.

16. In a system for controlling display of visual data from a computer having an operator controlled keyboard on which command control means is supported, and interface means operatively connecting the command control means to the computer for controlling cursor movement^' on the display, a source of power, a plurality of directional force sensitive resistances connected to said source, and means respectively measuring said resistances for developing said plurality of directional signals in separate signal channels connected to the signal transmitting means.

17. In a system for controlling display of visual data from a computer having an operator- controlled keyboard on which command control means is supported and interface means operatively connecting the command control means to the computer for controlling cursor movement on the display, a source of power, a plurality of directional force sensitive resistances connected to said source, means respectively measuring said resistances for developing a plurality of directional signals in separate signal channels and signal transmitting means operatively connecting the signal generating means to the computer, said interface means including control terminals and means connecting the control terminals to the command control means for operational control thereof in response to momentary switching of voltage levels at the control terminals, said power source comprising voltage regulating means connected to the control terminals for supply of operating voltage therefrom to the command control means and means for preventing any adverse effect on the supply of voltage by said momentary voltage level switching.

18. In a system for controlling display of visual data from a computer, a cursor positioning control device comprising a keyboard, a single finger pressure pad mounted on the keyboard and pressure transducer means responsive to directional pressures exerted on said pad for generating a plurality of directional signals of magnitudes corresponding to said pressures.

19. The device as defined in claim 17, wherein said transducer means includes a source of power, a plurality of directional force sensitive resistances connected to said source, and means respectively measuring said resistances for developing said plurality of directional signals in separate signal channels.

20. The device as defined in, claim 18, wherein said, directional force sensitive resistances respectively extend along arcuate segments in operative underlying relation to the pressure pad, said segments enclosing a null zone centrally underlying the pressure pad.

21. The device as defined in claim 19, wherein each of said directional force sensitive resistances is established between a group of conductive fingers and a contact element spaced therefrom in a shunt mode configuration operatively underlying the pressure pad.

22. The device as defined in claim 20, wherein said conductive fingers from the respective groups overlap, and are dimensionally tappered to maintain a substantially constant contact surface area in all directions relative to said null zone.

23. The device as defined in claim 18, wherein each of said directional force sensitive resistances respectively extend along arcuate segments in operative underlying relation to the pressure pad, said segments enclosing a null zone centrally underlying the pressure pad.

24. The device as defined in claim 22, wherein said conductive fingers from the respective groups overlap, and are dimensionally tappered to maintain a substantially constant contact surface area in all directions relative to said null zone.