Patent ID: 12195074

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

With reference to the figures, embodiments are described of a device100,200′,200″,300,400, or component, for detecting the contact between a user's hand or hands and a steering wheel of a vehicle.

In all the embodiments, the device100,200′,200″,300,400comprises an electrically insulating support10and an electrically conductive track101,201,301,401(also called “first track”) which is fastened to the support10.

Track101,201,301,401is adapted to act as contact sensor.

Track101,201,301,401comprises, i.e. is shaped so as to comprise, a plurality of peaks11(or crests) alternated with a plurality of troughs12(or valleys) along a direction D. In other words, the peaks11and the troughs12alternate with one another, whereby there is a trough12after a peak11and there is a peak11after a trough12.

Track101,201,301,401advantageously is distributed over the support so that the surface of the track adapted to come into contact with a user's hand decreases along direction D, for example in the direction indicated by arrow D in the drawings, as for device100,200′,200″,300, or in the direction opposite to the direction indicated by arrow D, as for device400. Preferably, direction D is parallel to the longitudinal axis of device100,200′,200″,300,400. When the device is supported on a support plane, the longitudinal axis of the device is a rectilinear axis.

Preferably, such a decrease of the surface adapted to come into contact with a user's hand is a gradual decrease.

In particular, it is worth noting inFIGS.1A to4, that device100,200′,200″,300,400and the components thereof are illustrated in a condition in which device100,200′,200″,300,400is supported on a support plane.

As is described below, device100,200′,200″,300,400is flexible, whereby it may also take on other shapes, in particular when device100,200′,200″,300,400is arranged on the steering wheel9of a vehicle, for example around the steering wheel9.

It is also worth noting that support10is shown by mere way of example, it being understood that it may also have other shapes which are not shown, in particular according to the steering wheel9on which the device is intended to be arranged.

With particular reference toFIGS.1A to1E, in a first embodiment, the aforesaid distribution of track101over support10so that the surface of track101adapted to come into contact with a user's hand decreases, preferably gradually, along the direction D, is obtained by means of a track101in which the height h1, h2(FIGS.1C and1D) of the peaks11decreases along said direction D, for example in the direction indicated by arrow D.

As already mentioned, track101is adapted to act as contact sensor. For this purpose, track101comprises two end portions. Each end portion comprises an end1′,1″ (FIG.1A) which serves as pad for the connection to an electronic control unit (not shown).

The aforesaid peaks11and the aforesaid troughs12extend between the ends1′,1″, in particular between the aforesaid end portions.

Height h1of a peak11′ is greater than height h2of the next peak11″ along direction D, in the direction indicated by arrow D (FIG.1D).

Preferably, the height of any peak11along direction D is always higher than the height of the next peak11.

The height of the peaks11preferably decreases gradually one peak after the other. Preferably, the difference in height between any peak11and the next peak11is a constant, or substantially constant, value.

Preferably, the difference in height between any peak11and the next peak11is in a range between 0.1 and 1 mm.

Preferably, the height of peak11proximal to the end1′ (on the far left inFIG.1A) is in a range between 70 and 100 mm. Preferably, the peak11proximal to the end1′ is the peak having the maximum height with respect to the other peaks11.

Preferably, the height of the peak11distal from the end1′ (to the far right inFIG.1A) is in a range between 5 and 20 mm. Preferably, the peak11distal from the end1′ is the peak having the minimum height with respect to the other peaks11.

The heights h1, h2of the peaks11preferably correspond to the minimum distance between a straight line r1tangent to the top of a peak11and a straight line r2, r3tangent to the bottom of the trough12next to said peak11—with respect to the direction D—which in particular is next and adjacent to said peak11.

InFIG.1Dfor example, the height h1of peak11′ is equal to the minimum distance between the straight line r1, which is tangent to the top of peak11′, and the straight line r2, which is tangent to the bottom of trough12′. Similarly, the height h2of peak11″ is equal to the minimum distance between the straight line r1, which is tangent to the top of the peak11″, and the straight line r3, which is tangent to the bottom of the trough12″.

Preferably, the straight lines r1, r2, r3are parallel to one another.

Preferably, the straight line r1is tangent to the top of all the peaks11, while the straight lines r2and r3, as the other straight lines which are tangent to the bottom of the other troughs12, are separate from and parallel to one another.

Preferably, the heights of the peaks11are mutually parallel segments.

Preferably, the heights of the peaks11are segments perpendicular to direction D.

Preferably, the tops of the peaks11are curved stretches.

Preferably, the width “w” (FIG.1C) of track101is constant or substantially constant.

Alternatively, the width of the first track decreases along said direction D, in the same direction in which the height of the peaks11decreases.

Preferably, the width “w” of track101is between 0.5 and 2 mm.

Preferably, the gap “d” between the peaks11is constant, or substantially constant, along direction D. “Gap” means the minimum distance, parallel to direction D, between two consecutive peaks11. Gap “d” between the peaks11preferably is between 10 and 18 mm.

All peaks11preferably have the same width “a”. “Width of a peak” means the minimum distance “a”, in particular parallel to direction D, between two opposite stretches111,112of the same peak11. Preferably, but not exclusively, such stretches111,112are parallel to each other, and preferably also are perpendicular to direction D, as in the example shown. Typically, but not exclusively, the stretches111,112are joined to each other by the top of the peak.

Preferably, the overall length of track101is between 4000 and 6000 mm, such a length being measured along the whole path of track101.

Device100preferably also comprises a second electrically conductive track102fastened to support10. The second track102is distinct from the first track101.

The second track102is adapted to act as contact sensor. For this purpose, the second track102comprises two end portions. Each end portion comprises an end2′,2″ (FIG.1A) which acts as pad for the connection to the electronic control unit.

Track101and track102preferably are the only tracks adapted to act as contact sensors.

The second track102comprises a plurality of peaks21alternated by a plurality of troughs22along the aforesaid direction D, between the ends2′,2″, in particular between the aforesaid end portions. In other words, the peaks21and the troughs22alternate with one another, whereby there is a trough22after a peak21and there is a peak21after a trough22.

The number of peaks11of the first track101preferably is equal to the number of peaks21of the second track102. Therefore, the number of troughs12of the first track101is equal to the number of troughs22of the second track102.

The second track102is distributed over support10so that the surface of the second track102adapted to come into contact with a user's hand increases, preferably gradually increases, along the aforesaid direction D, in particular in the direction indicated by arrow D.

In particular, the height h3of a peak21′ is less than the height h4of the next peak21″ (FIG.1E) along direction D.

The height of any peak21along direction D preferably is always less than the height of the next peak21.

The height of the peaks21preferably gradually increases one peak after the other.

The difference in height between any peak21and the next peak21preferably is a constant, or substantially constant, value.

The difference in height between one peak21and the next peak21preferably is in a range between 0.1 and 1 mm.

The height of the peak21proximal to the end2′ (on the far left inFIG.1A) preferably is in a range between 5 and 20 mm. The peak21proximal to the end2′ preferably is the peak having the minimum height with respect to the other peaks21.

The height of the peak21distal from the end2′ (to the far right inFIG.1A) preferably is in a range between 70 and 100 mm. The peak21distal from the end2′ preferably is the peak having the maximum height with respect to the other peaks21.

The heights h3, h4of the peaks21preferably correspond to the minimum distance between a straight line r4tangent to the bottom of a peak21and a straight line r5, r6tangent to the top of trough22next to said peak21—with respect to the direction D—which in particular is next and adjacent to said peak21.

InFIG.1Efor example, the height h3of peak21′ is equal to the minimum distance between the straight line r4, which is tangent to the bottom of peak21′, and the straight line r5, which is tangent to the top of trough22′. Similarly, the height h4of peak21″ is equal to the minimum distance between the straight line r4, which is tangent to the bottom of peak21″, and the straight line r6, which is tangent to the top of trough22″.

The straight lines r4, r5, r6preferably are parallel to one another.

The straight line r4preferably is tangent to the bottom of all the peaks21, while the straight lines r4and r5, as the other straight lines which are tangent to the top of the other troughs22, are distinct from and parallel to one another.

The heights of the peaks21preferably are mutually parallel segments.

The heights of the peaks21preferably are segments which are perpendicular to direction D.

The bottoms of the peaks21preferably are curved stretches.

Width “w” of track102preferably is constant or substantially constant.

Alternatively, the width of the second track increases along said direction D, in the same direction in which the height of the peaks21increases.

Width “w” of track102preferably is between 0.5 and 2 mm.

Width “w” of the second track102preferably is equal to the width of the first track101.

Gap “d” between the peaks21preferably is constant, or substantially constant, along direction D. The gap between the peaks21preferably is between 10 and 18 mm.

The gap between the peaks21preferably is equal to the gap between the peaks11.

The peaks21preferably all have the same width “a”, which preferably is equal to the width of the peaks11of the first track101.

Each peak11of the first track101preferably is aligned with a respective peak21of the second track102, in particular aligned along an axis which is orthogonal to direction D.

As in the example shown inFIG.1A, the peaks11of the first track101and the peaks21of the second track102preferably extend in mutually opposite direction, in particular in height, preferably along respective directions which are transverse, preferably perpendicular, to direction D.

The bottoms of the peaks21preferably are curved stretches.

The top of each peak11of the first track101preferably is concave towards the concavity of the bottom of a respective peak21aligned therewith of the second track102.

The first track101and the second track102preferably are shaped so that the minimum distance “k” (FIG.1C), which is perpendicular to direction D, between the top of a peak11and the bottom of peak21aligned with said peak21, is equal for all the pairs of peaks11-21.

The overall length of the second track102preferably is between 4000 and 6000 mm, such a length being measured along the whole path of track102.

The overall length of the second track102preferably is equal to, or about equal to, the overall length of the first track101.

Device100optionally also comprises a third electrically conductive track103(FIG.1A-1B) fastened to support10.

The third track103is adapted to act as heating track.

The third track103comprises a first stretch131which extends parallel, or substantially parallel, to the first track101.

In particular, the first stretch131of the third track103comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks11and troughs12of the first track101.

Also the height of the peaks of the first stretch131of the third track103preferably decreases along direction D, in the same direction in which the height of the peaks11of the first track101decreases.

The number of peaks and troughs of the first stretch131preferably is equal to the number of peaks11and troughs12of the first track101.

When the second track102is also provided, the third track103preferably also comprises a second stretch132which extends parallel, or substantially parallel, to the second track102.

In particular, the second stretch132of the third track103comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks21and troughs22of the second track102.

Also the height of the peaks of the second stretch132of the third track103preferably increases along direction D, in the same direction in which the height of the peaks21of the second track102increases.

The number of peaks and troughs of the second stretch132preferably is equal to the number of peaks21and troughs22of the second track102.

The first stretch131and the second stretch132of the third track103are joined to each other by a union stretch133.

The third track103comprises two end portions, preferably only two end portions, each provided with two ends3′,3″ which act as pads for the connection to the electronic control unit.

The width of the third track103preferably is greater than width “w” of the first track101and with respect to width “w” of the second track102.

The width of the third track103preferably is constant or substantially constant.

The width of the third track103preferably is between 0.5 and 4 mm.

The distance, the minimum distance in particular, between the first stretch131of the third track103and the first track101preferably is between 2.5 and 4 mm, such a distance preferably being constant or substantially constant.

The distance, the minimum distance in particular, between the second stretch132of the third track103and the second track102preferably is between 2.5 and 4 mm, such a distance preferably being constant or substantially constant.

The third track103preferably is proximal to the periphery, or outline, of device100, in particular to the periphery of support10, and the first track101and the second track102(when provided) are distal with respect to the periphery of device100, in particular to the periphery of support10. Alternatively in a variant not shown, the first track and the second track (when provided) optionally are proximal to the periphery of the device, in particular to the periphery of the insulating support, and the third track is distal from the periphery, or outline, of the device, in particular with respect to the periphery of the insulating support.

Device100preferably also comprises a fourth electrically conductive track104fastened to support10.

The fourth track104serves as shielding track to avoid interferences, in particular capacitive couplings or electromagnetic interferences in general, between the first track101and the third track103and when provided, between the second track102and the third track103.

The fourth track104comprises a first stretch141which extends between the first track101and the third track103.

The first stretch141of the fourth track104preferably extends parallel, or substantially parallel, to the first track101and to the third track103.

In particular, the first stretch141of the fourth track104comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks11and troughs12of the first track101.

Also the height of the peaks of the first stretch141of the fourth track104preferably decreases along direction D, in the same direction in which the height of the peaks11of the first track101decreases.

The number of peaks and troughs of the first stretch141preferably is equal to the number of peaks11and troughs12of the first track101.

When the second track102is also provided, the fourth track104preferably also comprises a second stretch142which extends between the second track102and the third track103.

The second stretch142of the fourth track104preferably extends parallel, or substantially parallel, to the second track102.

In particular, the second stretch142of the fourth track104comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks21and troughs22of the second track102.

Also the height of the peaks of the second stretch142of the fourth track104preferably increases along direction D, in the same direction in which the height of the peaks21of the second track102increases.

The number of peaks and troughs of the second stretch142preferably is equal to the number of peaks11and troughs12of the second track102.

The first stretch141and the second stretch142of the fourth track104are joined to each other by a union stretch143.

The fourth track104comprises two end portions, preferably only two end portions, each provided with two ends4′,4″ which act as pads for the connection to the electronic control unit.

The width of the fourth track104preferably is constant or substantially constant.

The width of the fourth track104preferably is between 0.5 and 2 mm.

The width of the fourth track104preferably is equal to, or about equal to, the width of the first track101.

The first stretch141of the fourth track104preferably is equally spaced from, or about equally spaced from, the first track101and from the third track103, and the second stretch142of the fourth track104is equally spaced from, or about equally spaced from, the second track102and from the third track103.

With particular reference toFIGS.2A to2D, in a second embodiment of a device200′,200″, the aforesaid distribution of the track over the support so that the surface of the track adapted to come into contact with a user's hand decreases along direction D, is obtained by means of a track201in which width w1, w2(FIG.2C) of the first track201decreases along said direction D, for example in the direction indicated by arrow D.

In all the embodiments, width of the track means the measurement taken parallel to the surface of support10and perpendicular to the axis of the track. Thickness of the track instead means the measurement taken perpendicular to the surface of support10and to the axis of the track.

As already mentioned, track201is adapted to act as contact sensor. For this purpose, track201comprises two end portions. Each end portion comprises an end1′,1″ (FIG.2A) which acts as pad for the connection to the electronic control unit (not shown).

The aforesaid peaks11and the aforesaid troughs12extend between the ends1′,1″, in particular between the aforesaid end portions.

In greater detail, the aforesaid reduction in width of track201is along the path of track201, i.e. along the actual length of track201.

The reduction in width of track201preferably is gradual.

By mere way of example, the reduction in width may occur stretch after stretch, i.e. any one stretch always has a greater constant width than the constant width of the next stretch, in particular in the direction of direction D indicated by the arrow.

The width of the track preferably, but not exclusively, decreases by 1% to 2.5% for each stretch.

The width of track201preferably decreases by a constant value.

By mere way of example, each stretch having constant, or substantially constant, width may be formed by a peak11and the next trough12, in particular by the start of a rectilinear stretch111of a peak11up to the start of the rectilinear stretch111of the next peak11.

For example, with particular reference toFIG.2C, the width of a first stretch of track201formed by a first peak11′-trough12′ pair has a width “w1”; and the width of a second stretch of track201, adjacent and next to the first stretch, formed by a second peak11″-trough12″ pair has a width “w2” (trough12″ is partially shown inFIG.2C). Width w2is from 1% to 2.5% smaller with respect to width w1, for example about 1% smaller.

Alternatively, by mere way of example, the reduction in width may also occur between stretch111and stretch112of the same peak. In particular, stretch112may have a smaller width with respect to stretch111of the same peak, and a greater width with respect to stretch111of the next peak, and so on.

The peaks11preferably have the same width “a”. “Width of a peak” means the minimum distance “a”, in particular parallel to direction D, between two opposite stretches111,112of the same peak11. Preferably, but not exclusively, such stretches111,112are parallel to each other, and preferably also are perpendicular to direction D, as in the example shown. Typically, but not exclusively, the stretches111,112are joined to each other by the top of the peak.

The height of the peaks11preferably is constant, or substantially constant, i.e. it is preferable for all the peaks11to have the same height. Alternatively, the height of the peaks11may decrease, substantially as described for the first embodiment, in the same direction in which the width of track201decreases.

The height of the peaks11preferably is between 30 and 60 mm.

The overall length of track201preferably is between 4000 and 6000 mm, such a length being measured along the whole path of track201.

Gap “d” between the peaks11preferably is constant, or substantially constant, along direction D. In other words, the gap between any pair of consecutive peaks11is a constant, or substantially constant, value. “Gap” means the minimum distance, parallel to direction D, between two consecutive peaks11. The gap between the peaks11preferably is between 10 and 18 mm.

Device200′,200″ preferably also comprises a second electrically conductive track202′,202″ fastened to support10. The second track202′,202″ is distinct from the first track201.

The second track202′,202″ is adapted to act as contact sensor. For this purpose, the second track202′,202″ comprises two end portions. Each end portion comprises an end2′,2″ which acts as pad for the connection to the electronic control unit.

Track201and track202′,202″ preferably are the only tracks adapted to act as contact sensors.

The second track202′,202″ comprises a plurality of peaks21alternated by a plurality of troughs22along the aforesaid direction D, between the ends2′,2″, in particular between the aforesaid end portions. In other words, the peaks21and the troughs22alternate with one another, whereby there is a trough22after a peak21and there is a peak21after a trough22.

The number of peaks11of the first track201preferably is equal to the number of peaks21of the second track202′,202″, Therefore, the number of troughs12of the first track201is equal to the number of troughs22of the second track202′,202″.

The second track202′,202″ is distributed over support10so that the surface of the second track202′,202″ adapted to come into contact with a user's hand increases along the aforesaid direction D.

In particular, the width w3, w4of the second track202′,202″ increases along said direction D, in the direction indicated by the arrow.

In greater detail, the aforesaid increase in width of track202′,202″ is along the path of track202, i.e. along the actual length of track202.

The increase in width of track202′,202″ preferably is gradual.

By mere way of example, the increase in width may occur stretch after stretch, i.e. any one stretch always has a smaller constant width than the constant width of the next stretch, in the direction of direction D indicated by the arrow.

The width of the track202′,202″ preferably, but not exclusively, increases by 1% to 2.5% for each stretch.

The width of track202′,202″ preferably increases by a constant value.

By mere way of example, each stretch having constant, or substantially constant, width may be formed by a peak21′ and the next trough22′.

For example, the width of a first stretch of track202′,202″ formed by a first peak21′-trough22′ pair has a width “w3”; and the width of a second stretch of track202′,202″, consecutive to the first stretch, formed by a second peak21″-trough22″ pair has a width “w4” (trough22″ is partially shown inFIG.1C). Width w4is from 1% to 2.5% greater with respect to width w3, for example about 1% greater.

Alternatively, by mere way of example, the increase in width may also occur between stretch111and stretch112of the same peak. In particular, the stretch112may have a greater width with respect to stretch111of the same peak, and a smaller width with respect to stretch111of the next peak, and so on.

The manner in which the increase in width of track202′,202″ occurs preferably is similar to the manner in which the decrease in width of track201occurs.

The overall length of the second track202′,202″ preferably is between 4000 and 6000 mm, such a length being measured along the whole path of track202′,202″.

The overall length of the second track202′,202″ preferably is equal to, or about equal to, the overall length of the first track201.

The peaks21preferably have the same width “a”, which preferably is equal to the width of the peaks11of the first track201.

The height of the peaks21preferably is constant, or substantially constant, i.e. it is preferable for all the peaks11to have the same height. Alternatively, the width of the peaks21may increase in the same direction in which the width of the second track increases.

The height of the peaks21of the second track202′,202″ preferably is equal to, or about equal to, the height of the peaks11of the first track201.

The height of the peaks21preferably is between 30 and 60 mm.

The gap between any pair of consecutive peaks21preferably is a constant, or substantially constant, value.

The gap between the peaks21preferably has an extension between 10 and 18 mm.

The gap between the peaks21preferably is equal to gap d between the peaks11.

Each peak11of the first track201preferably is aligned with a respective peak21of the second track202′,202″, in particular aligned along an axis which is perpendicular to direction D.

In a first variant of the second embodiment (FIGS.2A-2B-2C), the peaks11of the first track101and the peaks21of the second track202′ extend in mutually opposite direction, in particular in height, preferably along respective directions which are transverse, preferably perpendicular, to direction D.

In the first variant, the first track201and the second track202′ preferably are shaped so that the minimum distance “k” (FIG.1C), which is perpendicular to direction D, between the top of a peak11and the bottom of peak21aligned with said peak11, is equal for all the pairs of peaks11-21.

In a second variant of the second embodiment (FIG.2D), the peaks11of the first track201and the peaks21of the second track202″ extend in the same direction. The second track202″ preferably extends parallel, or substantially parallel, to the first track201.

In both variants, device200′,200″ optionally also comprises a third electrically conductive track203fastened to support10.

The third track203is adapted to act as heating track.

The third track203comprises a first stretch231which extends parallel, or substantially parallel, to the first track201.

In particular, the first stretch231of the third track203comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks11and troughs12of the first track201.

The number of peaks and troughs of the first stretch231preferably is equal to the number of peaks11and troughs12of the first track201.

When the second track202′,202″ is provided, the third track203in both variants comprises a second stretch232which extends parallel, or substantially parallel, to the second track202′,202″.

In particular, the second stretch232of the third track203comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks21and troughs22of the second track202′,202″.

The number of peaks and troughs of the second stretch232preferably is equal to the number of peaks21and troughs22of the second track202′,202″.

The first stretch231and the second stretch232of the third track203are joined to each other by a union stretch233.

The third track203comprises two end portions, preferably only two end portions, each provided with two ends3′,3″ which act as pads for the connection to the electronic control unit.

The width of the third track203preferably is greater than the maximum width of the first track201and with respect to the maximum width of the second track202′,202″.

The width of the third track203preferably is constant or substantially constant.

The width of the third track203preferably is between 0.5 and 4 mm.

The distance, the minimum distance in particular, between the first stretch231of the third track203and the first track201preferably is between 0.7 and 3 mm, such a distance preferably being constant or substantially constant.

The distance, the minimum distance in particular, between the second stretch232of the third track203and the second track202′,202″ preferably is between 0.7 and 3 mm, such a distance preferably being constant or substantially constant.

The third track203preferably is proximal to the periphery, or outline, of device200′,200″, in particular to the periphery of support10, and the first track201and the second track202′,202″ (when provided) are distal with respect to the periphery of device200′,200″, in particular to the periphery of support10. Alternatively in a variant not shown, the first track and the second track (when provided) optionally are proximal to the periphery of the device, in particular to the periphery of the insulating support, and the third track is distal from the periphery, or outline, of the device, in particular with respect to the periphery of the insulating support.

Device200′,200″ preferably also comprises a fourth electrically conductive track204fastened to support10.

The fourth track204serves as shielding track to avoid interferences, in particular capacitive couplings or electromagnetic interferences in general, between the first track201and the third track203and when provided, between the second track202′,202″ and the third track203.

The fourth track204comprises a first stretch241which extends between the first track201and the third track203.

The first stretch241of the fourth track204preferably extends parallel, or substantially parallel, to the first track201and to the third track203.

In particular, the first stretch241of the fourth track204comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks11and troughs12of the first track201.

The number of peaks and troughs of the first stretch241preferably is equal to the number of peaks11and troughs12of the first track201.

When the second track202′,202″ is also provided, the fourth track204preferably also comprises a second stretch242which extends between the second track202′,202″ and the third track203.

The second stretch242of the fourth track204preferably extends parallel, or substantially parallel, to the second track202′,202″.

In particular, the second stretch242of the fourth track204comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks21and troughs22of the second track202′,202″.

The number of peaks and troughs of the second stretch242preferably is equal to the number of peaks21and troughs22of the second track202.

In the second variant, the sequence of tracks, for example parallel to direction D, preferably is the following: third track203, fourth track204, first track201, second track202″, fourth track204, third track203.

The first stretch241and the second stretch242of the fourth track204are joined to each other by a union stretch243.

The fourth track204comprises two end portions, preferably only two end portions, each provided with two ends4′,4″ which act as pads for the connection to the electronic control unit.

The width of the fourth track204preferably is constant or substantially constant.

The width of the fourth track204preferably is between 0.5 and 2 mm.

The width of the fourth track204preferably is equal to, or about equal to, the width of the first track201.

The height of the peaks of the fourth track204preferably is constant or substantially constant.

The height of the peaks of the fourth track204preferably is between 30 and 60 mm, or between 31 and 63 mm.

The first stretch241of the fourth track204preferably is equally spaced from, or about equally spaced from, the first track201and from the third track203, and the second stretch241of the fourth track204is equally spaced from, or about equally spaced from, the second track202′,202″ and from the third track203.

With particular reference toFIGS.3A and3B, in a third embodiment of device300, the aforesaid distribution of the track over the insulating support10so that the surface of the track adapted to come into contact with a user's hand decreases along a direction D, is obtained by means of a track301wherein the width a1, a2of the peaks11increases along said direction D. InFIGS.3A and3B, in particular, the surface of the first track301adapted to come into contact with a user's hand decreases along direction D, in the direction indicated by the arrow. Indeed, track301thins out in the direction indicated by the arrow, and therefore decreases the available surface, while the track instead thickens in the direction opposite to that indicated by the arrow, and therefore increases the available surface.

As already mentioned, track301is adapted to act as contact sensor. For this purpose, track301comprises two end portions. Each end portion comprises an end1′,1″ (FIG.3A) which acts as pad for the connection to the electronic control unit (not shown).

The aforesaid peaks11and the aforesaid troughs12extend between the ends1′,1″, in particular between the aforesaid end portions.

“Width of a peak” means the minimum distance (a1, a2inFIG.3B), in particular parallel to direction D, between two opposite stretches111,112of the same peak11. Preferably, but not exclusively, such stretches111,112are parallel to each other, and preferably are also perpendicular to direction D, as in the example shown. Typically, but not exclusively, the stretches111,112are joined to each other by the top of the peak.

Preferably, the width of the peaks11increases gradually peak after peak preferably along direction D in the direction indicated by the arrow inFIGS.3A and3B. In particular, each peak11preferably has a smaller width than the width of the next peak11along direction D in the direction indicated by the arrow inFIGS.3A and3B.

InFIG.3Bfor example, the width of a peak11′ is indicated by “a1” and the width of the next peak11″ is indicated by “a2”. Width a1is smaller than width a2.

The difference in width between any peak11and the next peak11—for example, the difference between width a2and width a1—preferably is in a range between 0.5 and 4 mm, and preferably is a constant value.

The width of the peak11proximal to the end1′ (on the far left inFIG.3A) preferably is in a range between 0.5 and 4 mm. Peak11proximal to end1′ preferably is the peak having the minimum width with respect to the other peaks11.

The width of peak11distal from end1′ (to the far right inFIG.3A) preferably is in a range between 3.5 and 28 mm. Peak11distal from end1′ (and proximal to end1″) preferably is the peak having the maximum width with respect to the other pairs of peaks11.

Gap d between any pair of consecutive peaks11preferably is a constant value. “Gap” means the minimum distance, parallel to direction D, between two consecutive peaks11. Gap “d” between the peaks11preferably is between 15 and 20 mm, or between 10 and 18 mm.

The height of the peaks11preferably is constant, or substantially constant, i.e. it is preferable for all the peaks11to have the same height.

The height of the peaks11preferably is between 30 and 60 mm.

Width “w” of track301preferably is constant or substantially constant. The width of track301preferably is between 0.5 and 2 mm.

The overall length of track301preferably is between 4000 and 6000 mm, such a length being measured along the whole path of track301.

Device300preferably also comprises a second electrically conductive track302fastened to support10. The second track302is distinct from the first track301.

The second track302is adapted to act as contact sensor. For this purpose, track302comprises two end portions. Each end portion comprises an end2′,2″ which acts as pad for the connection to the electronic control unit.

Track301and track302preferably are the only tracks adapted to act as contact sensors.

The second track302comprises a plurality of peaks21alternated by a plurality of troughs22along the aforesaid direction D, between the ends2′,2″, in particular between the aforesaid end portions. In other words, the peaks21and the troughs22alternate with one another, whereby there is a trough22after a peak21and there is a peak21after a trough22.

The width of the peaks21gradually decreases peak after peak preferably along direction D in the direction indicated by the arrow inFIGS.3A and3B. In particular, each peak21preferably has a greater width than the width of the next peak21along direction D in the direction indicated by the arrow inFIGS.3A and3B.

InFIG.3Bfor example, the width of peak21′ is indicated by “a3” and the width of the next peak21″ is indicated by “a4”. Width a3is greater than width a4.

The difference in width between any peak21and the next peak21—for example, the difference between width a3and width a4—preferably is in a range between 0.5 and 4 mm, and preferably is a constant value.

The width of peak21proximal to end1′ (on the far left inFIG.3A) preferably is in a range between 3.5 and 28 mm. Peak21proximal to end1′ (and distal from end1″) preferably is peak21having the maximum width with respect to the other peaks21.

The width of peak21distal from end1′ (on the far right inFIG.3A) preferably is in a range between 0.5 and 4 mm. Peak21distal from end1′ preferably is the peak21having the minimum width with respect to the other peaks21.

Gap “d” between any pair of consecutive peaks11preferably is a constant value, and preferably is equal to the gap between the peaks11of the first track301.

The height of the peaks21preferably is constant, or substantially constant, i.e. it is preferable that all the peaks21have the same height.

The height of the peaks21of the second track302preferably is equal to, or about equal to, the height of the peaks11of the first track301.

The height of the peaks21preferably is between 30 and 60 mm.

The width of track302preferably is constant or substantially constant.

The width of track302preferably is equal to width w of track301.

The width of track302preferably is between 0.5 and 2 mm.

The overall length of track302preferably is between 4000 and 6000 mm, such a length being measured along the whole path of track302.

The length of the second track302preferably is equal to the length of the first track301.

As shown inFIGS.3A,3B, the peaks11of the first track301and the peaks21of the second track302preferably extend in mutually opposite direction, in particular in height, preferably along respective directions which are perpendicular to direction D.

Also in the third embodiment, the device optionally comprises a third electrically conductive track303fastened to the insulating support10.

The third track303is adapted to act as heating track.

The third track303comprises a first stretch331which extends parallel, or substantially parallel, to the first track301.

In particular, the first stretch331of the third track303comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks11and troughs12of the first track301.

The gap between the peaks of the first stretch331of the third track303preferably is constant, or substantially constant, along direction D. Alternatively, the gap between the peaks of the first stretch331decreases in the direction in which the width of the peaks11increases.

The number of peaks and troughs of the first stretch331preferably is equal to the number of peaks11and troughs12of the first track301.

When the second track302is also provided, the third track303comprises a second stretch332which extends parallel, or substantially parallel, to the second track302.

In particular, the second stretch332of the third track303comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks21and troughs22of the second track302.

The gap between the peaks of the second stretch332of the third track303preferably is constant, or substantially constant, along direction D. Alternatively, the gap between the peaks of the second stretch332decreases in the direction in which the width of the peaks11increases.

The number of peaks and troughs of the second stretch332preferably is equal to the number of peaks21and troughs22of the second track302.

The first stretch331and the second stretch332of the third track303are joined to each other by a union stretch333.

The third track303comprises two end portions, preferably only two end portions, each provided with two ends3′,3″ which act as pads for the connection to the electronic control unit.

The width of the third track303preferably is greater than the width of the first track301and with respect to width of the second track302.

The width of the third track303preferably is constant or substantially constant.

The width of the third track303preferably is between 0.5 and 4 mm.

The distance, the minimum distance in particular, between the first stretch331of the third track303and the first track301preferably is between 0.7 and 2.2 mm, such a distance preferably being constant or substantially constant.

The distance, the minimum distance in particular, between the second stretch332of the third track303and the second track302preferably is between 0.7 and 2.2 mm, such a distance preferably being constant or substantially constant.

The third track303preferably is proximal to the periphery, or outline, of device300, in particular to the periphery of support10, and the first track301and the second track302(when provided) are distal with respect to the periphery of device300, in particular to the periphery of support10. Alternatively in a variant not shown, the first track and the second track (when provided) optionally are proximal to the periphery of the device, in particular to the periphery of the insulating support, and the third track is distal from the periphery, or outline, of the device, in particular with respect to the periphery of the insulating support.

Device300preferably also comprises a fourth electrically conductive track304fastened to support10.

The fourth track304serves as shielding track to avoid interferences, in particular capacitive couplings or electromagnetic interferences in general, between the first track301and the third track303and when provided, between the second track302and the third track303.

The fourth track304comprises a first stretch341which extends between the first track301and the third track303.

The first stretch341of the fourth track304preferably extends parallel, or substantially parallel, to the first track301and to the third track303.

In particular, the first stretch341of the fourth track304comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks11and troughs12of the first track301.

The number of peaks and troughs of the first stretch341preferably is equal to the number of peaks11and troughs12of the first track301.

The gap between the peaks of the first stretch341of the fourth track304preferably is constant along direction D.

When the second track302is also provided, the fourth track304comprises a second stretch342which extends between the second track302and the third track303.

The second stretch342of the fourth track304preferably extends parallel, or substantially parallel, to the second track302.

In particular, the second stretch342of the fourth track304comprises a plurality of peaks and troughs which extend parallel, or substantially parallel, to the peaks21and troughs22of the second track302.

The gap between the peaks of the second stretch342of the fourth track304preferably is constant along direction D.

The number of peaks and troughs of the second stretch342preferably is equal to the number of peaks21and troughs22of the second track302.

The first stretch341and the second stretch342of the fourth track304are joined to each other by a union stretch343.

The fourth track304comprises two end portions, preferably only two end portions, each provided with two ends4′,4″ which act as pads for the connection to the electronic control unit.

The width of the fourth track304preferably is constant or substantially constant.

The width of the fourth track304preferably is between 0.5 and 2 mm.

The width of the fourth track304preferably is equal to, or about equal to, the width of the first track301.

The first stretch341of the fourth track304preferably is equally spaced from, or about equally spaced from, the first track301and from the third track303, and the second stretch342of the fourth track304is equally spaced from, or about equally spaced from, the second track302and from the third track303.

With particular reference toFIG.4, in a fourth embodiment of a device400, the aforesaid distribution of the track over the insulating support10so that the surface of the track adapted to come into contact with a user's hand decreases along a direction D, is obtained by means of a track401wherein the gap d1, d2between the peaks11decreases along said direction D. InFIG.4in particular, the surface of track401adapted to come into contact with a user's hand decreases along direction D, in the opposite direction with respect to that indicated by the arrow. Indeed, the first track401thickens in the direction indicated by the arrow, and therefore increases the available surface, while it instead thins out in the opposite direction and therefore decreases the available surface.

As already mentioned, track401is adapted to act as contact sensor. For this purpose, track401comprises two end portions. Each end portion comprises an end1′,1″ (FIG.4) which acts as pad for the connection to the electronic control unit (not shown).

The aforesaid peaks11and the aforesaid troughs12extend between the ends1′,1″, in particular between the aforesaid end portions.

The term “gap” d1, d2, d3, d4means the minimum distance, parallel to direction D, between two consecutive peaks11.

Preferably, the gap between the peaks11decreases gradually for each pair of peaks11along direction D in the direction indicated by the arrow inFIG.4. In particular, preferably, each pair of peaks11has a greater gap with respect to the next pair of peaks11along direction D in the direction indicated by the arrow inFIG.4.

InFIG.4for example, the gap between a first pair of peaks11′-11″ is indicated by “d1”, and the gap between the next pair of peaks11″-11′″ is indicated by “d2”. Gap d1is greater than gap d2.

The difference in gaps between any pair of peaks and the next pair of peaks—for example, the difference between gap d2and gap d1—preferably is in a range between 0.5 and 1 mm.

The difference in gaps between any pair of peaks—for example pair11′-11″—and the next pair of peaks—for example pair11″-11′″—preferably is equal for all the pairs of peaks11.

The gap of the pair of peaks11proximal to end1′ (to the far left inFIG.4) preferably is in a range between 25 and 30 mm. The pair of peaks11proximal to end1′ (and distal from end1″) preferably is the pair of peaks having the maximum gap with respect to the other pairs of peaks11.

The gap of the pairs of peaks11distal from end1′ (to the far right inFIG.3A) preferably is in a range between 0.5 and 1 mm. The pair of peaks11distal from end1′ preferably is the pair of peaks having the minimum gap with respect to the other pairs of peaks11.

The height of the peaks11preferably is constant, or substantially constant, i.e. it is preferable for all the peaks11to have the same height.

The height of the peaks11preferably is between 30 and 60 mm.

The width of track401preferably is constant or substantially constant. The width of track401preferably is between 0.5 and 2 mm.

The peaks11preferably have the same width “a”. “Width of a peak” means the minimum distance “a”, in particular parallel to direction D, between two opposite stretches111,112of the same peak11. Preferably, but not exclusively, such stretches111,112are parallel to each other, and preferably are also perpendicular to direction D, as in the example shown. Typically, but not exclusively, the stretches111,112are joined to each other by the top of the peak.

The overall length of track401preferably is between 4000 and 6000 mm, such a length being measured along the whole path of track401.

Device400preferably also comprises a second electrically conductive track402fastened to support10. The second track402is separate from the first track401.

The second track402is adapted to act as contact sensor. For this purpose, track402comprises two end portions. Each end portion comprises an end2′,2″ which acts as pad for the connection to the electronic control unit.

Track401and track402preferably are the only tracks adapted to act as contact sensors.

The second track402comprises a plurality of peaks21alternated by a plurality of troughs22along the aforesaid direction D, between the ends2′,2″, in particular between the aforesaid end portions. In other words, the peaks21and the troughs22alternate with one another, whereby there is a trough22after a peak21and there is a peak21after a trough22.

The gap between the peaks21gradually increases for each pair of peaks21preferably along direction D in the direction indicated by the arrow inFIG.4. In particular, each pair of peaks21preferably has a smaller gap with respect to the next pair of peaks21along direction D in the direction indicated by the arrow inFIG.4.

InFIG.4for example, the gap between a first pair of peaks21′-21″ is indicated by “d3”, and the gap between the next pair of peaks21″-21′″ is indicated by “d4”. Gap d3is smaller than gap d4.

The difference in gaps between any pair of peaks21and the next pair of peaks21preferably is in a range between 0.5 and 1 mm.

The difference in gaps between a pair of peaks21and the next pair of peaks21preferably is equal for all the pairs of peaks21.

The difference in gaps between any pair of peaks21and the next pair of peaks21preferably is equal to the difference in gaps between any pair of peaks11and the next pair of peaks11of the first track401.

The gap of the pair of peaks21proximal to end1′ (to the far left inFIG.4) preferably is in a range between 25 and 30 mm. The pair of peaks21proximal to end1′ preferably is the pair of peaks having the minimum gap with respect to the other pairs of peaks21.

The gap of the pairs of peaks21distal from end1′ (to the far right inFIG.4) preferably is in a range between 0.5 and 1 mm. The pair of peaks21distal from end1′ (and proximal to end1″) preferably is the pair of peaks having the maximum gap with respect to the other pairs of peaks21.

The peaks21preferably have the same width “a”, which preferably is equal to the width of the peaks11of the first track401.

The height of the peaks21preferably is constant, or substantially constant, i.e. it is preferable for all the peaks21to have the same height.

The height of the peaks21of the second track402preferably is equal to, or about equal to, the height of the peaks11of the first track401.

The height of the peaks21preferably is between 30 and 60 mm.

The width of track402preferably is constant or substantially constant.

The width of track402preferably is equal to width w of track401.

The width of track402preferably is between 0.5 and 2 mm.

The overall length of track402preferably is between 4000 and 6000 mm, such a length being measured along the whole path of track402.

The length of the second track402preferably is equal to the length of the first track401.

As shown inFIG.4, the peaks11of the first track401and the peaks21of the second track402preferably extend in mutually opposite direction, in particular in height, preferably along respective directions which are transverse, preferably perpendicular, to direction D.

In general, in all embodiments, the device100,200′,200″,300,400is flexible. Device100,200′,200″,300,400belongs to the field of flexible electronics and may also be called flexible circuit or “Flex Foil”.

Preferably, but not exclusively, the tracks are incorporated in the insulating support10. For example, the tracks are arranged between two layers of insulating support10fastened to each other, thus substantially forming a sandwich structure.

One of the two layers of the insulating support10may be arranged on the body of the steering wheel9(for example, on the metal skeleton of the steering wheel or on another layer, for example made of polyurethane or another thermohardening/thermoplastic element of the body of the steering wheel), and the other insulating layer may be covered with a covering layer, made of leather for example. Thereby, the covering layer advantageously does not have protrusions due to the conductive tracks.

The tracks may alternatively be fastened to a surface, for example an outer face, of the insulating support10.

Device100,200′,200″,300,400preferably has an overall thickness between 0.1 and 1 mm, for example between 0.1 and 0.6 mm, or between 0.3 and 1 mm, or between 0.3 and 0.6 mm; for example, the thickness is equal to about 0.3 mm or is equal to about 0.6 mm.

The overall thickness of device100,200′,200″,300,400preferably is much smaller than the maximum length and the maximum width thereof, where such length and width substantially correspond to the maximum length and the maximum width of the insulating support10. For example, the length of device100,200′,200″,300,400may be between 900 and 1200 mm and the width may be between 80 and 160 mm, or between 80 and 100 mm. The dimensions of device100,200′,200″,300,400may in any case be selected according to the dimensions of any steering wheel on which it is provided for device100,200′,200″,300,400to be applied.

The material with which the insulating support10is made preferably is a polymeric material. By mere way of non-limiting example, the insulating support10may comprise or be made of silicone, PVC, PS, PP, PE, PC, ABS, PET, PA, PU, PUR, NBR, PTFE, EPDM and the like, optionally with additives. The insulating support preferably comprises or is made of PVC.

By mere way of non-limiting example, each conductive track may comprise or be made of aluminum, constantan, copper, German silver, steel, Inconel, brass and the like. The conductive tracks preferably are made of aluminum. The conductive tracks preferably each have a thickness between 10 and 200 μm, for example between 15 and 150 μm.

By mere way of non-limiting example, device100,200′,200″,300,400may be made by means of etching a foil fastened to support10, or by crosslinking a silicone support on which there are arranged one or more of the aforesaid conductive tracks obtained by means of cutting, e.g. laser cutting.

Preferably, device100,200′,200″,300,400, support10in particular, is extensible, being plastically and/or elastically deformable, up to about 10-20% with respect to a resting configuration or initial configuration.

By mere way of non-limiting example, a device100according to the first embodiment may be fastened to the steering wheel9as described below, referring in particular toFIGS.5A,5B,5C.

The steering wheel9for example, is shown inFIGS.5A and5Cin a position in which the wheels of the vehicle are straight, i.e. a position in which the vehicle may advance substantially in a straight line.

FIG.5Ais a front frontal view, whileFIG.5Cis a rear frontal view.

FIGS.5A and5Calso indicate direction D along which the surface of the first track101adapted to come into contact with a user's hand when device100is arranged on the steering wheel9, decreases. In particular, the surface of the first track101adapted to come into contact with a user's hand decreases in the direction inFIGS.5A,5C. Typically, but not exclusively, direction D depends on the shape of the steering wheel9. Typically, but not exclusively, direction D is parallel to the perimeter of the steering wheel9. For example, when device100is applied to a circular steering wheel9, direction D substantially is circular.

For illustrative purposes, axis Y is indicated, which divides the steering wheel9in half, in particular into a left-hand part93and into a right-hand part94, where “left-hand” and “right-hand” refer to a front frontal view of the steering wheel9(FIG.5A).

The front part of the steering wheel9is indicated by numeral91, while the rear part is indicated by numeral92. The front part91faces the driver.

The left-hand part93and the right-hand part94each comprise half of the front part91and half of the rear part92.

Device100is positioned so that the first track101is arranged at the front part91of the steering wheel9and so that the second track102(when provided) is arranged at the rear part92of the steering wheel9.

In greater detail, peak11aof the first track101having the maximum height is arranged in the front part91of the left-hand part93, preferably close to axis Y. The position of such a peak11ais diagrammatically indicated by the dotted line which ends with a dot inFIG.5A.

Peak11bof the first track101having the minimum height is arranged in the front part91of the right-hand part94, close to axis Y. The position of such a peak11bis diagrammatically indicated by the dotted line which ends with a square inFIG.5A.

Peak21aof the second track102having the minimum height is arranged in the rear part92of the left-hand part93(looking at the steering wheel from the front), close to axis Y. The position of such a peak21ais diagrammatically indicated by the dotted line which ends with a dot inFIG.5C. Therefore, peak21aof the second track102substantially is opposite to peak11aof the first track101.

Peak21bof the second track102having the maximum height is arranged in the rear part92of the right-hand part94(looking at the steering wheel from the front), close to axis Y. The position of such a peak21″ is diagrammatically indicated by the dotted line which ends with a square inFIG.5C. Therefore, peak21bof the second track102substantially is opposite to peak11bof the first track101.

The arrangement of device100just described also holds true for the devices200′,300and400, respectively, according to the second embodiment (first variant), the third and fourth embodiments.

For the device200″ according to the second variant of the second embodiment, the first track and the second track are arranged at the front part91and the rear part92of the steering wheel9.

Optionally, only a portion of the steering wheel, for example from 70% to 80% of the steering wheel, is provided with a device100,200′,200″,300,400. Thereby, any contact between other parts of the driver's body (e.g. his/her knees) and the steering wheel are not detected.

By mere way of non-limiting example, with reference to the following tables andFIGS.6A,6B,6C,7A,7B,7C,8A,8B,8C, a method is described for operating a device100according to the first embodiment in which both the first track101and the second track102are provided.

Such an operating method is also applicable to the devices200′,300and400.

TABLES1S2S1 ANDS1 ORContact method(101)(102)S2S2No. 1 Palm Left TouchH0FALSETRUENo. 1 Palm Right TouchL0FALSETRUENo. 2 Palm Left TouchH + H0FALSETRUENo. 2 Palm Right TouchL + L0FALSETRUENo. 1 Palm Left Touch +H + L0FALSETRUENo. 1 Palm Right TouchNo. 1 Grip Left TouchHLTRUETRUENo. 1 Grip Right TouchLHTRUETRUENo. 2 Grip Left TouchH + HL + LTRUETRUENo. 2 Grip Right TouchL + LH + HTRUETRUENo. 1 Grip Left Touch +HHTRUETRUENo. 1 Grip Right Touch

Device100is connected to an electronic control unit suitably programmed to execute such a method, thus forming a system or apparatus.

The method provides defining a threshold value for an electrical quantity, e.g. the capacitance.

With respect to such a threshold value, following the contact, also indirect contact, there may be a high variation of capacitance (indicated by letter “H” in the table), i.e. much greater than the threshold value, or a low variation of capacitance (indicated by letter “L” in the table), i.e. slightly greater than the threshold value, between the hand and the first track101, according to the area where the contact occurs.

Similarly with respect to such a threshold value, following the contact between the hand and the second track102, there may be a high variation of capacitance (H), i.e. much greater than the threshold value, or a low variation of capacitance (L), i.e. slightly greater than the threshold value, according to the area where the contact occurs. For example, the difference between a value H and the threshold value is between 8 and 20 pF (pico-Farad), and the difference between the value L and the threshold value is between 2 and 4 pF.

The capacitance value read by the electronic control unit advantageously varies according to the position in which the contact with the steering wheel9occurs.

It is to be understood that the contact between the hand and the first track and/or the second track102may also be an indirect contact. The contact preferably is indirect, i.e. the driver's hand touches an outer covering layer of the steering wheel, below which the device100is provided, and in particular below which there are the tracks101,102.

The threshold value preferably is the same for the two tracks101,102.

The threshold value is selected according to the variation of capacitance at the minimum touch value to be detected (e.g. 2 fingers), i.e. the minimum touch contact surface.

The table makes reference to a “Palm Left Touch” and “Palm Right Touch”, which indicate a contact only with the palm of a hand, in particular an open palm, in the front part91of the left-hand part93and in the front part91of the right-hand part94, respectively, of the steering wheel9.

Under these conditions, the driver only touches the front part91of the steering wheel, and therefore touches, also indirectly, only the first track101.

The table makes reference to a “Grip Left Touch” and “Grip Right Touch”, which indicate a grip, in particular with a closed hand, in the left-hand part93and in the right-hand part94, respectively, of the steering wheel9.

Under the condition of a grip of the steering wheel with a closed hand, the hand is in contact both with the front part91, and therefore touches, preferably indirectly touches, the first track101, and with the rear part92, and therefore touches, preferably indirectly touches, the second track102.

In the table, “N” followed by number “1” or by number “2” indicates the number of hands with which the contact occurs with the steering wheel9.

FIGS.6A,6B,6Cschematize a condition of “No. 1 Palm Left Touch” (contact to the left, with one hand alone with an open palm). The contact area Z1′ with the steering wheel9is shown diagrammatically inFIG.6Awith a rectangle, and the respective contact area Z1″ with the first track101is diagrammatically indicated by a rectangle inFIG.6B.

With reference to the first line in the table, under this condition, the variation of capacitance relative to the first track101read by the electronic control unit is “high” (H, column S1) with respect to the threshold value, while the variation of capacitance relative to the second track102substantially is equal to zero (0, column S2). Therefore, the following logical relations exist: “S1 and S2=False” and “S1 or S2=True”, i.e. it may be determined that there is no contact with both tracks, rather only with one of the two tracks, in particular only with track101.

Moreover, since the variation value of capacitance is high, an indication may be obtained of the area in which the contact occurs, which here is in the left-hand part93.

FIGS.7A,7B,7Cschematize a condition of “No. 1 Grip Left Touch” (sixth line in the table), i.e. a grip of the steering wheel to the left, with one hand alone. The contact areas Z2′ and Z2″ with the steering wheel9are shown with a rectangle inFIGS.7A and7C, respectively, and the respective contact area Z2′″ with the first track101and with the second track102are indicated by a rectangle inFIG.7B. It is worth noting that the surface of the first track101enclosed in rectangle Z2′″ is greater than the surface of the second track102enclosed in the same rectangle Z2′″. Therefore, the absolute variation value of capacitance related to the first track101is high (H, column S1) and in any case, is greater than the absolute variation value of capacitance related to the second track102, the latter being low (L, column S2).

Therefore, the following logical relations exist: “S1 and S2=True” and “S1 or S2=True”, i.e. it may be determined that there is contact with both the tracks101,102.

Moreover, since the variation value of capacitance related to the first track101is high, while the variation value of capacitance related to the second track102is low (i.e. the difference between the capacitance value of the first track101and the second track102is positive), it may be determined that the grip is occurring in the left-hand part93of the steering wheel.

With reference to the last line of the table,FIGS.8A,8B and8Cschematize the condition of “No. 1 Grip Left Touch+No. 1 Grip Right Touch”, i.e. of a grip with two hands, of which one hand arranged on the left-hand part93and one hand arranged on the right-hand part94.

In this case, the variation value of capacitance related to the first track101is high because it is given by the sum of a high value (left-hand part93) and of a low value (right-hand part94). Moreover, also the variation value of capacitance related to the first track102is high because it is given by the sum of a low value (left-hand part93) and of a high value (right-hand part94).

The fourth line of the table summarizes a condition of “No. 2 Palm Right Touch”, i.e. in which the driver touches the steering wheel only with his/her palm, with two hands only arranged in the right-hand part94, close to axis Y. Here, there is the sum of two low values (L+L, column S1).

If the devices100,200′,300and400are provided with one conductive track101,201,301,401only, preferably arranged on the front part91, and in the case of device200″ (second variant of the second embodiment) in which the two conductive tracks201and202″ are both preferably arranged on the front part91, the position where the contact with the steering wheel9occurs may in any case be determined.

In general, in all embodiments in which there are provided two sensor tracks, for example the tracks101and102, the capacitance value C1of track101and the capacitance value C2of track102may be processed using the formula:
(C1−C2)/(C1+C2).

This formula allows normalizing the difference (C1−C2) with respect to the entity of the touch. In other words, it allows always having a result between −1 and 1, regardless of the absolute value of C1and C2.

The result is used for detecting the position of the touch.

For example, considering a contact with one hand only, the result of the formula tends to be 1, the closer the proximity to peak11a(maximum height); moreover, the result of the formula tends to be −1, the closer the proximity to peak11b(minimum height) and tends to be 0, the closer the proximity to the middle of device100.

Note that, preferably, the end values of the value ranges indicated in this description are included.