WO2016059448A1

WO2016059448A1 - Capacitive sensor arrangement for distinction of large object from finger

Info

Publication number: WO2016059448A1
Application number: PCT/IB2014/065264
Authority: WO
Inventors: Robil Tian SUPATRIO; Renshi LI; Arunkumar NARAYANAN
Original assignee: Continental Automotive Gmbh
Priority date: 2014-10-13
Filing date: 2014-10-13
Publication date: 2016-04-21

Abstract

A sensor arrangement for operating a movable surface of a passenger car comprises a base substrate with a plurality of longitudinal conductive strips on one side of the base substrate and a plurality of lateral conductive strips on an opposite second side of the base substrate. First connectors are provided for connecting the plurality of lateral conductive strips with an evaluation unit, and second connectors are provided for connecting the plurality of longitudinal conductive strips with the evaluation unit.

Description

CAPACITIVE SENSOR ARRANGEMENT FOR DISTINCTION OF LARGE OBJECT FROM FINGER

The current application relates to an improved switch for sunroof of a motor vehicle and in particular to an improve proximity sensor arrangement. In particular, the motor veh cle may be a passenger car, a multipurpose car, such as an SUV, or a small truck, such as a pickup car.

Movable windows and sunroofs in present day passenger vehicles are often equipped with switch-operated electric motors instead of the hand cranks that were in use in earlier times . Typically, a switch for a sunroof provides a first position for moving the sunroof out and a second position for moving the sunroof back in. If the sunroof is pivotable, the switch also provides one or more positions for tilting the sunroof in and out, such as for example a 3-way button switch. While the use of electric motors enhances the user comfort, it may also increase the risk that a power window or a sunroof is operated by accident, especially by children.

Regulation authorities have directed their attention to this issue and have devised corresponding safety regulations . For example, paragraph S6 of the US safety regulation FMVSS 118 (49 CFR 571.118) specifies, in the version of August 2014, that switches for power-operated window, partition, and roof panel systems must pass an accidental actuation test with a stainless steel sphere having a surface finish between 8 and 4 micro inches and a radius of 20 mm +0.2 mm.

During the actuation test, the surface of the sphere is placed against any portion of the actuation device and a force not greater than 135 Newtons (30 pounds) is applied through the geometric center of the sphere. This force may be applied at any angle with respect to the actuation device. When the force is applied to any switch or to the housing surrounding a switch that can be used to close a power- operated window, partition, or roof panel, such application must not cause the window, partition, or roof panel to begin to close.

According to the standard FMVSS 118, the actuation test is not required for switches, which are both roof-mounted and incapable of "one-touch" closure, and it is not required for switches, which meet the automatic reversal requirements of paragraph S5 of the above-mentioned regulation.

The automatic reversal requirement specifies that, during closing, a power-operated window, partition, or roof panel shall stop and reverse direction either before contacting a test rod with properties described in sections S8.2 or S8.3 of the same standard, or before exerting a squeezing force 100 Newtons (N) or more on a semi-rigid cylindrical test ro with the properties described in section S8.1 of the same standard, when such test rod is placed through the window, partition, or roof panel opening at any location

A corresponding directive 2000/4/EC of the European Parliament and of the Council of 28 February 2000 amending Council Directive 74/60/EEC specifies conditions under which a sunroof may close. Those conditions do not specify a test with steel sphere that is similar to the abovementioned test. Sim ilar to US law, the closing conditions are waived for a sunroof with an auto reverse feature. It is an object of the present specification to provide an improved control unit for a sunroof of a passenger car.

In a sensor arrangement according to an embodiment of the present application a capacitive touch pattern, which is recorded by a first set of three or more narrow conductive strips that are aligned in a first direction, allows a distinction between a test ball and a finger. A second set of four or more conductive strips, which are aligned in a second direction, that is provided at an angle to the first direction, are used to capture a movement of a finger or a test object. These four or more sensor strips provide a movement sensor arrangement, which is also referred to as capacitive slider. In a preferred embodiment, the second direction is substantially perpendicular to the first direction.

The first set of conductive strips, which function as proximity sensors, provide a higher sensitivity, or even a much higher sensitivity than the second set of conductive strips. Among others, the sensitivity of the proximity sensors can be enhanced with respect to the movement sensors by placing the proximity sensors at a front side of a PCB and by placing the movement sensors at a back side of the PCB.

A sensor arrangement according to the present specification provides a simple and cost-effective way to operate a sunroof and at the same time to differentiate between a test ball and a finger according to the FMVSS 118 safety regulation. The sun-roof is operated by sliding a finger along a sliding direction, which is also referred to as vertical axis or direction. The sliding direction is parallel to a first set of proximity sensors, which are also referred to as "vertical proximity sensors". In particular, if the first set of proximity sensors comprises parallel strips of a conductive material, the sliding direction is parallel to an orientation of the parallel strips. The first set of proximity sensors is used to distinguish a finger from a test object, such as a metal sphere according to the FMVSS 118 safety regulation.

In particular, the first set of proximity sensors may com- prise three vertical proximity sensors. The three vertical proximity sensors can be used to detect an object larger tha a finger, such as a test ball, When the test ball is placed near to the vertical proximity sensors, for example near to one of the vertical proximity sensors, it will excite more o the neighbouring vertical proximity sensors than a finger.

In general, capacitive sensors may be used as touch sensors or as proximity sensors. The electrode of a capacitive sensor represents one plate of such a capacitor, the sensor electrode. The corresponding second plate is represented by the environment of the sensor electrode to form a parasitic capacitor CO and another conductive or a dielectric object, like a human finger for example to form touch capacitor Ct . This sensor electrode of the capacitor is connected to a measurement circuit.

In a sensor arrangement according to the present specification, the capacitance of the sensor pad may be measured periodically or continuously. If a conductive object approaches or touches the electrode, the measured capacitance increases. This change is detected by the measurement circuit and converted into a trigger signal. In a sensor arrangement accord- fication, the

^■, for example

g a response,

nt or a chang

The present application discloses a sensor arrangement for operating a movable surface of a sunroof of a passenger car.

The sensor arrangement comprises a base substrate with one o more substrate layers. In particular, the base substrate can be provided by a printed circuit board (PCB) , which provides stability. According to another embodiment, the base substrate is provided by one or more flexible plastic layers.

The base substrate comprises two or more longitudinal conduc tive strips, which are aligned in parallel on a first side o the base substrate. The longitudinal conductive strips are provided for distinguishing a fingertip from a test object within a detection range.

The longitudinal conductive strips are provided on the sur- face of the base substrate or PCB, which is next to the inte rior of the passenger compartment in an installed state , and they function as proximity sensors .

A distinction between a finger and a test object is already possible with to longitudinal strips. However, three or more longitudinal strips can provide a larger lateral extension. This makes it easier for a passenger to aim at the sensor arrangement with the finger, especially if the sensor arrangement is provided in a ceiling of the passenger compartment. According to one embodiment, a finger only triggers one proximity sensor, which corresponds to one longitudinal conductive strip, but the test object triggers two or more proximity sensors, which correspond to two or more longitudinal conductive strips. Herein, a sensor is triggered when a response signal from the sensor is above a pre-determined trigger threshold.

A plurality of lateral conductive strips are aligned in par- allel on a second side of the base substrate, opposite to first side. The lateral conductive strips form a capacitive slider, for detecting a finger movement . The lateral conduc- tive strips are provided at an angle to the lateral conduc- tive strips .

In particular, a sensor arrangement in which the lateral conductive strips are provided essentially perpendicular to the longitudinal conductive strips is convenient to produce and to operate. In particular, the expression "essentially perpendicular" or "substantially perpendicular" may refer to an angle between 80 and 110 degrees, or, more specifically, between 85 and 95 degrees. Herein, the angle is measured parallel to the plane of the first side, which is essentially parallel to the plane of the second side.

The control unit has a touch sensitive surface or touch screen with three or more first or "horizontal" proximity sensors, which extend along a first direction and with two or more second or "vertical" proximity sensors, which extend along a second direction. The second direction is provided at an angle of at least 45 degrees to the first direction in a plane of the touch sensitive surface. The conductive strips are also referred to as "proximity sensors" in connection with their operation as proximity sensors . The longitudinal strips are also referred to as vertical strips or vertical sensors and the lateral strips are also referred to as horizontal strips or horizontal sensors. The longitudinal conductive strips are separated from each other by at least a predetermined first distance. Likewise, the horizontal conductive strips are separated from each other by at least a predetermined second distance.

Thereby, intermediate areas or interspaces are formed between the first and the second proximity sensors. A distinction between a test ball and a fingertip is performed uniformly across both the sensors and the intermediate areas between the sensors .

Furthermore, the sensor arrangement comprises first connectors for electrically connecting the plurality of lateral conductive strips with an evaluation unit and second connectors for electrically connecting the plurality of longitudinal conductive strips with the evaluation unit.

By way of example, the evaluation unit may be connected to the conductive surfaces by conductive strips or cables or by a data line of a data bus of the passenger car. The PCB may comprise or it may be connected to a signal converter, which converts the raw sensor signals into signals of the car's data bus .

The longitudinal sensors are separated from each other by a least a predetermined distance, such that a capacitive pattern caused by a finger is different from a capacitive pattern caused by a conductive test object having a similar or bigger dimension than a human fingertip which is placed at the same position as the test object. The distinction can b made within a pre-determined detection range of the sensors In a sensor arrangement according to the present specification, an accidental triggering by objects that are at a dis tance from a sensor surface can be avoided.

Furthermore, an overlay is provided to protect the first side of the base substrate. The overlay is sufficiently thin and made from a suitable material such that a sensitivity of the capacitive sensors, which are formed by the capacitive surfaces, is not affected too strongly.

For convenient handling and integration in the passenger com partment the sensor arrangement may furthermore be provided with a casing. The evaluation unit may be provided within th casing or outside of the casing. The overlay may be recessed with respect to the casing, for example to avoid accidental operation of the sensor.

In one particular embodiment, the lateral dimensions of the longitudinal conductive strips and the mutual distances between the longitudinal conductive strips are such that a capacitive pattern caused by a metallic test ball with a radius of 20 mm +/- 0.2 mm is different from a capacitive pattern caused by a human fingertip at the same positions and within a pre-determined detection range .

According to one embodiment, the plurality of longitudinal conductive strips comprises at least three longitudinal conductive strips. The longitudinal strips are aligned in paral lei and preferentially they are equally spaced. In particular, lateral spaces in between the longitudinal strips can b made substantially larger than the lateral dimension of the longitudinal strips, for example at least three times larger, to provide enough room for the finger to operate the capaci- tive slider and to provide a good distinction between the finger and the test object.

In a particular embodiment, which provides a good distinction between the finger and the test object, a lateral dimension or extension of the longitudinal conductive strips is between 10 mm and 30 mm and a lateral dimension of the longitudinal conductive strips is between 2 mm and 6 mm. According to a more specific embodiment, the longitudinal dimension of the longitudinal strips is between 18 and 22 mm, and a lateral dimension of the longitudinal conductive surfaces is between 3 mm and 5mm. Specifically, the longitudinal extension of the longitudinal conductive strips may be between 40 mm and 80 mm or, more specifically, between 55 mm and 65 mm, thereby providing a sensor that is both compact and easy to operate.

In one embodiment, at least four lateral conductive strips are provided. While a capacitive slider may also be formed with only two or only three conductive strips, at least four conductive strips can provide a smoother operation of the capacitive slider, a larger target area and a better capturing of the finger movements.

In a specific embodiment, a mutual distance between the lateral conductive strips is between 5 mm and 15 mm and a lateral dimension of the lateral conductive strips is between 5mm and 10mm, while in a more specific embodiment, a mutual distance between the lateral conductive strips is between 9 mm and 11mm, and a lateral dimension of the lateral conductive strips is between 6 mm and 8 mm. These dimensions pro- vide a good interaction with the user, especially for a standard thickness PCB board between 0.5 and 2.5 mm and, more specifically, for a thickness between 1mm and 1.5 mm.

In one embodiment, a longitudinal dimension of the lateral conductive strips is between 40mm and 60mm, or, more specifically between 45 mm and 55 mm. Among others, these longitudinal dimensions can provide a target area that is convenient to aim at. With respect to the conductive strips, "longitudinal" refers to the direction of longest extension of the strips and "lateral" refers to a direction perpendicular to the longitudinal direction within the plane of the conductive strips .

Furthermore, the present specification discloses a control unit with the abovementioned sensor arrangement. The control unit comprises an evaluation unit, which is electrically connected to the first connectors of the longitudinal conductive strips and to the second connectors of the lateral conductive strips .

The evaluation unit measures at least one capacity value of the sensor arrangement. The capacity value corresponds to a charge that can be placed on a conductor for a given voltage. In particular, the conductor may correspond to one or more conductive strips. In one embodiment, the evaluation unit measure at least one capacity value for each of the conductive strips of the sensor arrangement.

According to an embodiment of the present specification, the evaluation unit is operative to distinguish a response signal of a metallic test ball, especially of a test ball with a radius of 20 mm +/- 0.2 mm according to the FMVSS 118 regula- tion, from a response signal of a human fingertip by evaluating at least electric signals from the longitudinal conductive strips. According to a further embodiment, the evaluation unit also evaluates electric signals of the lateral conductive strips to distinguish the finger from the test ob- j ect .

The functions of the evaluation unit may be provided, by way of example, by a computer readable memory with suitable computer readable instructions and/or by a standard circuitry or integrated circuits and/or by custom-made or special purpose circuitry, such as ASICS.

In particular, the longitudinal conductive strips and or the lateral conductive strips can be separately connected to the evaluation unit to provide a good capture of a capacitive pattern for measuring individual capacity values . It is preferred to use one and the same evaluation unit or controller for evaluating the electric signals from the longitudinal and the lateral conductive strips such that the scanning of the strips is synchronized and unwanted interferences due to un- synchronized scanning times can be avoided.

A separate connection includes an arrangement with separate physical connections that are connected to the evaluation unit and also an arrangement with separate connections that are mapped to one or more connections via a demultiplexer or a serializer, wherein the one or more connections are connected to the evaluation unit .

According to one embodiment, the evaluation unit is operative to evaluate electric signals from the lateral conductive strips, to derive a slider position from those electric sig- nals and to detect finger gestures by evaluating the slider position. In particular, the finger gestures may correspond to an opening gesture, a closing gesture or a tilting gesture, which cause an opening, closing or tilting of the movable surface, respectively.

According to an embodiment comprising a sunroof, the processing unit is operative to detect an opening gesture and to open the sunroof in response, to detect a closing gesture and close the sunroof in response, and to detect a tilting gesture and tilt the sunroof in response. The gestures refer to movements of a user's hand on a touch sensitive surface of the sensor arrangement. The touch sensitive surface may be provided by a surface of the base substrate, or the surface of an overlay. The evaluation of the gestures can provide a further means for distinguishing between accidental and intended movements .

Furthermore, the present specification discloses an electric drive for a movable or a slidable surface of a car, such as a movable surface of a sunroof or a window of a windows lifter. The movable surface separates an interior space of a passenger compartment from an exterior space in a closed state. The electric drive comprises the abovementioned control unit and is connected to a control output of the evaluation unit.

The present specification discloses furthermore a sunroof with the abovementioned electric drive, wherein a movable surface of the sunroof is mechanically connected to the electric motor by power transmission means such as one or more wires, ropes, belts, gears, levers or a combination thereof. Moreover, the present specification discloses a passenger car with the abovementioned sunroof, wherein the control unit is arranged in a passenger compartment of the passenger car such that it can be reached from a driver's seat, for example next to the sunroof in the ceiling, in the centre console, in the dashboard, or on the car's A-column.

In a further embodiment, the present specification disclose a passenger car with the abovementioned sunroof, wherein the control unit is provided in a ceiling of a passenger compartment of the passenger car.

An outer surface of the sensor arrangement which faces to the car's interior, and which is also referred to as a touch screen surface, may be sunk-in or recessed with respect to the ceiling or the surrounding surface of the passenger compartment to provide a further means to avoid an accidental operation .

The embodiments of the present specification are now explained in further detail with respect to the following Figures in which

Figure 1 shows a sunroof of a vehicle with a control unit, Figure 2 shows an isometric view of sensor arrangement of the control unit of Fig. 1,

Figure 3 shows an operation of the control unit of Fig. 1 by a user,

Figure 4 shows a controller portion of the control unit of

Fig. 1,

Figure 5 shows an isometric view of the control unit of Fig. Figure 6 shows a cross sectional view through the sensor arrangement of Fig. 5, and

Figure 7 shows a side view on the sensor arrangement of Fig.

5.

In the following description, details are provided to describe the embodiments of the present specification. It shall be apparent to one skilled in the art, however, that the embodiments may be practised without such details.

Figure 1 shows a ceiling 11 of a passenger compartment of a passenger car 10 from below. The ceiling 11 comprises a sunroof 12. The sunroof 12 comprises an actuation mechanism, which is not shown in Fig. 1. The actuation mechanism is connected to a control unit 13, which is provided next to the sunroof 12.

The sunroof 12 comprises a movable surface element 14 or panel, which is provided by a transparent surface in the example of Fig. 1. In other embodiments, the movable surface element 14 comprises metallic parts or a metallic panel.

In further embodiments, a control unit 13 is provided in a location that can be reached comfortably by a driver who is seated on a driver seat of the passenger compartment. For example, it may be provided on an A-pillar of the car, on a centre console, in a dashboard, in a car entertainment system or at a front side of the sunroof between the sun visors of a car's windscreen.

During operation, a user operates the control unit 13 in a first mode of operation to slide the surface element 14 of the sunroof 12 in and out of a compartment, which is provided in the ceiling 11. In a second mode of operation, the user operates the control unit 13 to tilt the movable surface 14 with respect to the horizontal. In one embodiment, the movable surface 14 can be tilted around a pivot axis at a front side 15 of the movable surface 14 to adjust a height of a gap at a rear side 16 of the movable surface 14.

In one embodiment, a movement of the movable surface, such as the tilting motion or the sliding motion is triggered by a gesture of a user's fingertip on a surface of the control unit 13. This provides a convenient user interface and another possibility to distinguish an intentional operation from an accidental touch.

Figure 2 shows a simplified isometric view of a sensor arrangement 18 of the control unit 13 of Fig. 1. In the sensor arrangement 18 four horizontal capacitive sensors 20, 21, 22, 23 are arranged on the backside of a printed circuit board (PCB), which is not shown in detail in Fig. 2, and three vertical capacitive sensors 24, 25, 26 are arranged on a front side of the PCB. The front side of the PCB is provided on the side where the finger sliding operation is performed. The front side is provided opposite to the backside and faces towards the interior of the passenger cell.

The PCB is covered by an overlay that comprises an overlay material such as glass, FR-4, kapton, acrylic, polycarbonate, or acrylonitrile butadiene styrene (ABS) plastic. In particular, the overlay may be a transparent overlay, which comprises a transparent material.

The vertical proximity sensors 24, 25, 26 are provided by vertical copper strips that extend from a first horizontal boundary 30 to a second horizontal boundary 31 of the rectangular sensitive area 29 at the front side of the PCB. A sensitivity of the vertical capacitive sensors is suitable for use of the vertical capacitive sensors as proximity sensors.

Similarly, the four horizontal capacitive sensors 20 - 23 are provided by horizontal copper strips that extend from a first vertical boundary 27 to an opposite second vertical boundary 28 of a rectangular sensitive area 29 at the back side of the PCB. The four horizontal capacitive sensors 20 - 23 together form a capacitive slider. The capacitive slider allows to detect a sliding motion of a finger on an upper surface along the vertical direction.

The capacitive sensors 20 - 26 form a regular grid on the sensitive area 29, wherein intermediate areas 32 of dimensions d W x d H are not covered by proximity sensors. A sub- region of the sensitive area 29, which is covered by the proximity sensors 20 - 26, forms a proximity sensor area 33.

According to one specific embodiment, a width w H of the vertical strips 24, 25, 26 in a horizontal direction is 4 mm and the vertical strips are spaced apart by a horizontal distance d H of 20 mm. Furthermore, a width w V of the horizontal strips 20, 21, 22, 23 in a vertical direction is 7 mm, the horizontal strips are spaced apart by a vertical distance d V of 10 mm. In this embodiment, the vertical strips have a dimension of 60 mm x 4 mm, the horizontal strips have a dimension of 50 mm x 7 mm and the spaces 32 between the strips have a dimension of 20 mm x 10 mm. The PCB has a thickness of 1.2 mm. Experiments have shown that these dimensions and inter- spacings provide a good differentiation between the test ball according to the FMVSS 118 safety regulation and a human finger. In general, a minimum distance between the proximity sensors is such that a test object produces a unique capaci- tive pattern when it is located in the inter-space between two proximity sensors. This minimum distance depends, among others, on the size of the test object and the size of the PCB.

Herein, a vertical direction refers to a direction parallel to the first and second vertical boundaries 27, 28 in the plane of the sensitive area 29 and a horizontal direction refers to a direction parallel to the first and second horizontal boundaries 30, 31 of the sensitive area 29. In the embodiment of Fig. 2, an extension of the sensitive area 29 in the horizontal direction is smaller than an extension of the sensitive area 29 in the vertical direction.

In a further embodiment, the sensitive area 29 may have a different shape from the shape of Fig. 2. For example, the sensitive area 29 may have the shape of a parallelogram, in which case the intermediate areas 32, which are not covered by proximity sensors, also have the shape of parallelograms.

Fig. 3 shows a hand 35 of a user, which is touching the sensitive area 29 with a fingertip 36 of the hand 35. According to the present specification, the sensor arrangement is formed such that the presence of a fingertip 36 in proximity to the sensitive area 29 can be differentiated from the presence of a metal test ball with an approximate radius of 20 mm. According to the present specification, a low resolution of for example 4 vertical and 3 horizontal sensors on the sensitive surface 29 is sufficient to distinguish between the metal test ball and a fingertip 36.

Furthermore, the vertical and horizontal sensors form a grid of intersecting strips. The dimensions of the strips and their mutual distances are adjusted such that a metal ball excites more sensors than a fingertip, due to its larger size .

Fig. 4 shows a controller portion of the control unit 13 of Fig. 1, in which output lines of the capacitive sensors 20 to 26 are connected to an evaluation unit 38. The evaluation unit 38 comprises, among others, a microprocessor 39 and a memory 40. The memory comprises a program for evaluating output signals of the capacitive sensors 20 to 26. A control line 41 is connected to a motor 42, which is mechanically connected to the sunroof 12, in particular to the movable surface 14 of the sunroof 12, for example by a lever mechanism, a belt, a tooth gear mechanism, a rack and pinion mechanism or a combination thereof.

In further embodiments, the evaluation of the sensor signal is carried out partially or completely by application specific electronic components such as electronic circuits, ASICS or programmable electronic components, such as EPROMS, or any combination thereof.

Fig. 5 shows a second isometric view of the sensor arrangement 18 of Fig. 1, in which a thickness of a printed circuit board 17 is indicated by the letter "d" . Lateral strip-shaped copper layers 50, 51, 52, 53 are provided on a back side or rear side of the printed circuit board 17 and longitudinal strip-shaped copper layers 54, 5 5, and 56 are provided on a rear side of the printed circuit board . The first and second copper layers are also referred to as conductive surfaces or conductive strips .

The conductive strips form 50 to 56 a first plate of one of the capacitive sensors 20 to 26, respectively. The second plate of the respective capacitive sensor 20 to 26 is formed by the environment of the respective first plate 50 to 56.

The copper layers 50 to 56 are individually connected to the evaluation unit 38, which is shown in more detail in Fig. 4, via connection lines 100, 101, 102, 103, 104, 105, 106, respectively. The connection lines or the corresponding signal paths are also referred to as "channels". For the sake of simplicity, multiple connection lines are indicated by diagonal lines.

When a finger approaches the conductive surfaces or strips, which are provided by copper layers 50 to 56, a charge that can be loaded on the sensors for a given voltage changes. In one embodiment, the evaluation unit measures the change of charge of the i-th conductive strip and converts the measure ment into digital values C i. The larger the charge on the sensors, the larger the digital value C i. Herein, the index i runs from 1 to n for n conductive strips.

The evaluation unit may then determine a position on a capac- itive slider by using a "center-of-gravity" formula, such as

∑₌₁ i * (Q— threshold(i))

Slider Pos =

∑"₌₁ Q— threshold ^) wherein Slider Pos is the slider position and threshold (i) is a detection threshold of the i-th sensor. In one embodiment, C i represents a difference from an average capacity. For example, the difference C i may be determined by subtracting the measured capacity from a low pass filtered capacity value .

By evaluating a time dependence of the slider position, the evaluation unit can detect finger gestures. For example, an opening gesture may correspond to an increase in the slider position and a closing gesture may correspond to a decrease of the slider position.

By way of example, a first tilting gesture may correspond to holding the finger at a first position for a minimum time, and a second tilting gesture may correspond to holding the finger at a second position for a minimum time. For example, in an arrangement with four lateral conductive strips the first tilting gesture may correspond to Slider Pos < 2 for a minimum time and the second tilting gesture may correspond to Slider Pos > 2 for a minimum time.

There are various other ways of deriving user gestures from electric signals of the conductive strips, which are not explained in further detail.

The connections shown in Fig. 5 provide one of several possi ble ways of connecting the copper layers 50 to 56 of the respective capacitive sensors 20 to 26. In a resistively inter polated arrangement, the respective copper layers 50 - 53 an 54 - 56 are connected among each other via resistances and only some of the copper layers 50 - 56 are connected to the evaluation unit 38. In one embodiment, separate connections are only provided to the last and the first copper surface in a row and an intermediate copper surface. In other embodiments, some of the conductive strips may be connected to ground and some of the conductive strips may be connected to each other.

The embodiments of the current specification can also be described with the following lists of elements being organized into items. The respective combinations of features which ar disclosed in the item list are regarded as independent subject matter, respectively, that can also be combined with other features of the application.

In the current specification, an indication such as 20 mm +/- 0.2 mm refers to a range of values having 20 mm - 0.2mm as lower boundary and 20 mm + 0.2 mm as upper boundary. Thus, a range of 20 mm +/- 0.2 mm indicates a range of values between 19.8 mm and 20.2 mm.

1. A sensor arrangement for operating a movable surface of a passenger car, the sensor arrangement comprising a base substrate, the base substrate comprising

a plurality of longitudinal conductive strips on one side of the base substrate,

a plurality of lateral conductive strips on a second side of the base substrate,

first connectors for connecting the plurality of lateral conductive strips with an evaluation unit, and

second connectors for connecting the plurality of longitudinal conductive strips with the evaluation unit . The control unit according to item 1, wherein the lateral dimensions of the longitudinal conductive strips and the mutual distances between the longitudinal conductive strips are such that a capacitive pattern cause by a metallic test ball with a radius of 20 mm +/- 0.2 mm is different from a capacitive pattern caused by a fingertip . The sensor arrangement according to item 1 or item 2, wherein the lateral conductive strips are inclined by an angle of substantially 90 degrees with respect the longitudinal conductive strips.

The sensor arrangement according to one of the preceding items, wherein the plurality of longitudinal conductive strips comprises at least three longitudinal conductive strips .

The sensor arrangement according to one of the preceding items, wherein a distance between the longitudinal con- ductive strips is between 10 mm and 30 mm and a lateral dimension of the longitudina1 conductive surfaces is be- tween 2 mm and 6 mm.

The sensor arrangement according to one of the preceding items, wherein the plurality of lateral conductive strips comprises at least four conductive strips.

The sensor arrangement according to one of the preceding items, wherein a mutual distance between the lateral conductive strips is between 5 mm and 15 mm and a lateral dimension of the lateral conductive strips is between 5 mm and 10 mm. A control unit comprising a sensor arrangement accordin to one of the preceding items, the control unit compris ing an evaluation unit, wherein the evaluation unit is electrically connected to the first connectors and to the second connectors of the sensor arrangement, and wherein the evaluation unit measures at least one capac ity value of the sensor arrangement.

The control unit according to item 8 , wherein the longi tudinal conductive strips are separately connected to the evaluation unit , and wherein the evaluation unit measures individual capacity values of the longitudinal conductive strips .

The control unit according to item 8 or item 9, wherein the lateral conductive strips are separately connected to the evaluation unit, and wherein the evaluation unit measures individual capacity values of the lateral con- ductive strips .

The control unit acccoorrddiinngg ttoo oonnee ooff the items 8 to 9, wherein the evaluatiioonn uunniitt iiss ooppeerraative to evaluate electric signals froomm tthhee llaatteerraall ccoonductive strips , to derive a slider posiittiioonn ffrroomm tthhee eellectric signals and to detect finger gessttuurreess bbyy eevvaalluuaatting the slider posi tion .

An electric drive for a movable surface of a car, where in the movable surface separates an interior space of a passenger compartment from an exterior space, the elec- trie drive comprising a control unit according to one o the items 8 to 11, the electric motor being connected to a control output of the evaluation unit.

13. A sunroof with an electric drive according to item 12, wherein a movable surface of the sunroof is mechanically connected to the electric motor.

14. A passenger car with a sunroof according to item 13, the control unit being arranged in a passenger compartment of the passenger car such that it can be reached from a driver's seat.

15. A passenger car with a sunroof according to item 13, wherein the control unit is provided in a ceiling of a passenger compartment of the passenger car.

Although the above description contains much specificity, these should not be construed as limiting the scope of the embodiments but merely providing illustration of the foreseeable embodiments . Especially the above stated advantages of the embodiments should not be construed as limiting the scope of the embodiments but merely to explain possible achievements if the described embodiments are put into practise. Thus, the scope of the embodiments should be determined by the claims and their equivalents, rather than by the examples given. For example, the conductive strips need not be rectangular but may have other shapes and the connections of the conductive strips may be different from those of the embodiments according to the Figures. Reference

10 passenger car 32 intermediate area

11 ceiling 33 proximity sensor area

12 sunroof 35 hand

13 control unit 36 fingertip

14 movable surface element 38 evaluation unit

15 front side 40 memory

16 rear side 41 control line

17 printed circuit board 42 electric motor

18 sensor arrangement 50 copper layer

19 sliding direction 51 copper layer

20 capacitive sensor 52 copper layer

21 capacitive sensor 53 copper layer

22 capacitive sensor 54 copper layer

23 capacitive sensor 55 copper layer

24 proximity sensor 56 copper layer

25 proximity sensor 101 connection line

26 proximity sensor 102 connection line

29 rectangular sensitive 103 connection line

area 104 connection line

30 first horizontal bound105 connection line

ary 106 connection line

31 second horizontal

boundary

Claims

second connectors for connecting the plurality of longitudinal conductive strips with the evaluation unit .

The control unit according to claim 1, wherein the lateral dimensions of the longitudinal conductive strips and the mutual distances between the longitudinal conductive strips are such that a capacitive pattern caused by a metallic test ball with a radius of 20 mm +/- 0.2 mm is different from a capacitive pattern caused by a fingertip .

The sensor arrangement according to claim 1, wherein the lateral conductive strips are inclined by an angle of substantially 90 degrees with respect the longitudinal conductive strips .

The sensor arrangement according to claim 1, wherein the plurality of longitudinal conductive strips comprises at least three longitudinal conductive strips .

The sensor arrangement according to claim 1, wherein a distance between the longitudinal conductive strips is between 10 mm and 30 mm and a lateral dimension of the longitudinal conductive surfaces is between 2 mm and 6 mm.

6. The sensor arrangement according to claim 1, wherein the plurality of lateral conductive strips comprises at least four conductive strips .

7. The sensor arrangement according to claim 1, wherein a mutual distance between the lateral conductive strips is between 5 mm and 15 mm and a lateral dimension of the lateral conductive strips is between 5 mm and 10 mm.

A control unit comprising a sensor arrangement according to claim 1, the control unit comprising an evaluation unit, wherein the evaluation unit is electrically connected to the first connectors and to the second connectors of the sensor arrangement, and wherein the evaluation unit measures at least one capacity value of the sensor arrangement.

The control unit of claim 8, wherein the longitudinal conductive strips are separately connected to the evalu- ation unit, and wherein the evaluation unit measures in- dividual capacity values of the longitudinal conductive strips .

10. The control unit according to claim 8, wherein the lat- eral conductive strips are separately connected to the evaluation unit, and wherein the evaluation unit measures individual capacity values of the lateral conductive strips .

The control unit according to claim 8, wherein the evaluation unit is operative to evaluate electric signals from the lateral conductive strips, to derive a slider position from the electric signals and to detect finger gestures by evaluating the slider position.

An electric drive for a movable surface of a car, wherein the movable surface separates an interior space of a passenger compartment from an exterior space, the electric drive comprising a control unit according to claim 8, the electric motor being connected to a control output of the evaluation unit .

A sunroof with an electric drive according to claim 12, wherein a movable surface of the sunroof is mechanically connected to the electric motor.

A passenger car with a sunroof according to claim 13, the control unit being arranged in a passenger compartment of the passenger car such that it can be reached from a driver's seat.

A passenger car with a sunroof according to claim 13 , wherein the control unit is provided in a ceiling of a passenger compartment of the passenger car .