Patent ID: 12197661

DESCRIPTION OF A PREFERRED EMBODIMENT

The present invention thus relates to a pointing device, comprising a control device with an actuator cylinder and a holder or central shaft, intended to be located between a computer keyboard and a user.

FIG.1shows in perspective, obliquely from above, a pointing device1according to the invention with a control device2comprising a user-displaceable/translatable/rotatable, essentially rigid actuator cylinder3. The pointing device1includes a housing4which can be provided with a palm rest on its upper surface5, buttons/keys for various computer functions etc (not shown). The actuator cylinder3can be moved laterally by the user and/or rotated via an operating opening6arranged in the upper surface5of the housing.

When the user rotates the actuator cylinder3with his hand and/or fingers, the cursor is moved vertically on the computer monitor and when the actuator cylinder3is displaced in its axial direction, the cursor is moved horizontally on the monitor. Thus, the cursor can be moved freely by the user over the entire surface of the monitor.

FIG.2shows a pointing device in a similar perspective view as inFIG.1, but with the upper housing part of the pointing device1removed. The actuator cylinder3of the control device2is, with its end cups3a,b, here arranged in a holder, a beam7awith a V-shaped groove, in which the actuator cylinder3can both be laterally displaced and rotated. The beam7ais in turn arranged for limited movement in a vertical direction in relation to the pointing device1and its bottom and rests on compressible springs10a,bin such a way that the actuator cylinder3and its holder, the beam7a, in a mechanically unaffected position, its “rest position”, is at a suitable height above the bottom of the pointing device1.

A user's depressing of the actuator cylinder3results in a limited vertical movement of the actuator cylinder3and the holder/beam7ain the direction of the bottom of the pointing device1and if the vertical movement has gone far enough so that a predetermined limit value is reached, preferably 1 mm, this results in that a “click” function is initiated.

An optical sensor8is arranged to the side of the actuator cylinder3and mounted on a motherboard9, and thus fixed in relation to the bottom of the pointing device1.

A sensor11ain the form of a Hall element is arranged below the beam7a, preferably at or near the center of the beam7a. A magnet12ais arranged below the beam7aand placed directly above the sensor11aso that the sensor11adetects changes in the strength of the magnetic field when the beam7ais moved in a vertical direction. The distance between the magnet12aand the sensor11ais preferably about 1.5 mm when the beam7aand the actuator cylinder3are in rest position.

The sensor11athus detects positional changes of the actuator cylinder3in relation to the bottom of the pointing device1.

The sensor11aand the magnet12aare preferably located in the same axial position, seen in relation to the beam7a, as the optical sensor8.

The optical sensor8is located at such a distance from the actuator cylinder3that its optics are focused on the surface/periphery of the actuator cylinder3, whereby the sensor8detects each axial displacement, vertical movement and rotation of the actuator cylinder3and generates an output signal S1(seeFIG.3). This output signal is then fed to a signal processing unit13a.

FIG.3shows a simple block diagram of the electrical signals of the sensors8,11aand their processing. The signal processing is here only described in principle and the sensors8,11acan also be of a different design than that described above and can, for example, emit analog or digital signals.

In the present embodiment, the sensor11ais exemplified as a Hall element, mounted on the motherboard9, which in combination with the magnet12afunctions as a position-sensitive sensor. However, the position-sensitive detection can also take place capacitively, inductively or optically.

A vertical movement, “clicking”, of the actuating cylinder3, generates a change in the first sensor's8signal value S1which, uncompensated, would result in an incorrect/unwanted vertical downward cursor movement on the monitor of a computer connected to the pointing device.

However, this unwanted vertical curser movement is compensated with the help of a signal processing unit13aby subtracting a second signal value S2, from the second position-sensitive sensor11a, which is proportional to the vertical movement of the actuator cylinder3, from the first signal value S1and thereby reducing/eliminating the unwanted vertical cursor movement on the monitor when “clicking on the actuator cylinder”.

The signal processing unit13athus subtracts the signal value S2, which is only proportional to the vertical position change of the actuator cylinder3, from the signal value S1which is proportional to the rotation and position change of the actuator cylinder3in the vertical direction, whereby a resulting signal value S3is obtained which is only proportional to the real/actual rotation. The signal value S3in turn affects the position of the cursor on a connected computer.

When the signal value S2reaches a predetermined threshold value, the signal processing unit13ainterprets this as a “click” which is forwarded to the connected computer.

FIG.4shows an alternative control device2with an actuator cylinder3arranged rotatably around a central shaft7band where the shaft in turn is limited in vertical movement via its suspension in springy end pieces14a,b.

Compressible springs10a,bare arranged between the bottom of the pointing device1and the end pieces14a,bin such a way that the actuator cylinder3and its holder, the central shaft7b, in a mechanically unaffected position, rests at a suitable height above the bottom of the pointing device1. Position-sensitive sensors11b,c, preferably of the Hall element type, arranged below the respective end pieces14a,b, detect the vertical position of the actuator cylinder3and if a user presses the actuator cylinder3down sufficiently against the bottom of the pointing device1, so that a pre-determined threshold value is reached, this results in a “click” function being initiated. By the fact that two sensors11b,care arranged according to this design example, one under each end piece14a,b, it is possible to compensate for, in the signal processing unit13b, if the actuator cylinder3is pressed down asymmetrically, i.e. if one end is pressed down more than the other.

Here too, at the bottom of the pointing device1, a motherboard9is arranged on which the optical sensor8is in turn arranged/fixed. The optical sensor8is located to the side of the actuator cylinder3and directed towards the actuator cylinder's3surface. The sensor8detects all movements of the actuator cylinder3and emits a first signal value S1which is fed to a signal processing unit13b(seeFIG.6).

FIG.5shows in more detail the suspension of the actuator cylinder3, whereby the end piece14bis thus movable in a vertical direction via the spiral spring10b. The figure shows how the central axis7bof the control device2is suspended in an end piece14bat one end. A magnet12cis arranged under the end piece14band a sensor11cis arranged on the motherboard9. The distance between the magnet12cand the sensor11cis typically about 1.5 mm when the actuator cylinder3and the shaft7bare at rest. The strength of the magnetic field detected by the sensor11cincreases with decreasing distance to the magnet12c. The sensor11cgenerates a signal value S2bwhich is proportional to the vertical position of the end piece14bin relation to the sensor11c.

Similarly, the sensor11bin combination with the magnet12bdetects the vertical position of the end piece14a, whereby a signal S2ais generated.

FIG.6shows a block diagram of the processing of the electrical signals. The signal values S2a,bare subtracted in the signal processing unit13bfrom the signal value S1. The resulting signal value S3controls the cursor on a computer monitor connected to the system.

The signal processing unit13aalso sums the signal values S2aand S2b. When this sum reaches a predetermined threshold value, the signal processing unit13ainterprets this as a “click” which is forwarded to the connected computer.

The description above is primarily intended to facilitate the understanding of the invention, but the invention is of course not limited to the specified embodiments, but also other variants of the invention are possible and conceivable within the scope of the invention and of the enclosed patent claims.