In an electromagnetic digitizer tablet having a grid of receptor wire disposed below a working surface over which a cursor emanating a magnetic field detected by the receptor wires is moved, this invention is an improvement to reduce electrostatically-caused jitters in data from the receptor wires. A grounded electrically conductive shield disposed between the grid of receptor wires and the working surface. The grounded electrically conductive shield is of a material and thickness to pass the magnetic field without substantial attenuation while conducting any electrostatic energy forming thereon to ground. Both conductive ink and a very thin metal foil can be used for the shield. The digitizer tablet is also shown embodied in the input/display device of a pen-driven computing system.

A touch-control mouse provides rapid and accurate control of the positioning of a cursor on a computer display screen, and includes a laminated touch-control film assembly, an aluminum supporting board, a press button switch set, a signal processing circuit board, and a dust-protective hanging case. Drawing using a finger on x-axis and y-axis resistance planes of the laminated touch-control film assembly results in variable potential value for x, y coordinates. The value of potential variation is calculated through a single-chip microprocessor to indicate relative direction, speed and amount of displacement on x, y coordinates. The signal of the relative direction, speed and amount of displacement is further is further sent by the single-chip microprocessor through a standard RS-232 connector to one of the serial communications ports of a PC to rapidly and accurately control the positioning of the cursor on the computer display screen.

Method and apparatus for educational games comprising a plurality of printed cards/boards, and a novel low-cost touch pad with interface cable to the personal computer game-port. When an eductional game is played, the player responds to computer questions/words/graphic object by pressing the corresponding answer in the printed card/board which is placed on top of the touch pad. This selection in terms of touched coordinates of the touch pad is sensed by the computer through the computer input/game port. Both computer generated sound and animation graphic pictures in terms of video games or others are used for either positive or negative feedback to the player. A variation of the same apparatus can be used for playing various computerized board games with a plurality of moving game pieces, and game boards by one or more players.

An automatic position coordinate determining device comprises a data tablet which has a single magnetostrictive element in which strain waves are induced for determining the position coordinates of a pointer relative to a pair of mutually orthogonal coordinate axes obliquely disposed with respect to the magnetostrictive element. Two mutually orthogonal pluralities of parallel equidistantly spaced electrical conductors form a grid network on the top surface of the tablet. These pluralities of conductors are wrapped around the edge of the tablet and spatially compressed to form respective X and Y conductor grids over opposing quadrants of the tablet bottom surface. A movable pointer travels along the top surface of the tablet while the magnetostrictive element is arranged along the diagonal of the tablet bottom surface. The conductors of the X and Y grids are inductively coupled to the diagonal magnetostrictive element. When the pointer is pulsed, a current pulse is induced in at least one electrical conductor of each plurality, following which oppositely propagating strain waves are induced in the magnetostrictive element by the pulsed electrical conductor. The propagation times of the strain waves are determined and the position coordinates of the pointer are calculated therefrom.

The invention is directed to a membrane switch comprising a first layer 30 of flexible insulating material and a second layer 50 having relatively inflexible characteristics, each layer 30, 50 having an array of conductors 40, 54 disposed thereon and defining a plurality of switch point areas over a substantial portion of the respective layers. The first sheet is transparent and carries visible symbols on the inner surface thereof formed by a first layer 36 of inks printed thereon and further includes a barrier coating over such symbols to provide contrast therefore. The first array 40 of conductors is printed on the barrier coating. The second array 54 of conductors is printed on the inflexible layer. The first and second arrays 40, 54 of conductors are connected to respective voltage sources, preferably by further arrays of conductors 42, 56 disposed over at least portions of the first and second arrays, 40, 54 the further arrays 42, 56 being of a material having a higher conductivity than the material used for the first and second arrays 40, 54. Spacer means 58 for the switch is formed by printing an array of spaced apart dots of a dielectric and insulating coating on top of at least one of the arrays of conductors in the defined switch point areas to hold the switch point areas normally apart until pressure is placed thereupon to deform the first sheet 30 and effect a switch closure between corresponding switch point areas of the arrays 40, 54. A method for making the switch is also disclosed.