Seat component and seat, particularly of a motor vehicle

Abstract

The invention relates to a seat element (16) comprising a mattress (18) and a cover arranged around the mattress; the seat element comprising two lateral longitudinal edges (24, 26); a first side (32) of the seat element being located on one side of a longitudinal central plane, a second side (34) being located on the other side of the longitudinal central plane; the seat element comprising a first capacitive sensor (36) with coplanar interdigitated electrodes arranged on the first side (32) and a second capacitive sensor (42) with coplanar interdigitated electrodes arranged on the second side (34); the second capacitive sensor (42) being separated from the first capacitive sensor (36) along a longitudinal direction (X) by a first distance (D1) of between 30 millimeters and 50 millimeters and preferably by a first distance (D1) equal to 40 millimeters. Figure to be published with the abbreviation: Figure 2

Description

Title of the invention: Seat element and seat, in particular for motor vehicles Technical field of the invention

[0001] The present invention relates to a seat element and a seat comprising this seat element. In particular, the present invention relates to a removable seat cushion that can be attached to and placed on the backrest or seat of a chair. Prior art

[0002] Some people adopt an unsuitable sitting position on a seat or chair such as an office chair, a medical chair or a vehicle seat. This unsuitable posture can cause them back pain.

[0003] In particular, drivers often tend to slouch in their seats or hunch over due to fatigue or loss of muscle tone during long car journeys. Some drivers twist their spines while driving with one hand or turning towards their neighbor. These postures are not ergonomic and can cause lower back pain. Some cars may have a seat equipped with a poor posture detection function. For cars that do not have this function, a seat element such as a removable cushion with this function can be fitted to the seat.

[0004] This seat element must not only be suitable for people of different body shapes but also for seats of different dimensions. In particular, in the field of motor vehicles, it would be desirable for the removable cushion to be suitable for vehicle seats of category A, category B, or category C. Presentation of the invention

[0005] A first objective of the present invention is to provide a seat element capable of detecting poor postures of seat occupants with different morphologies and regardless of the size of the seat on which it is mounted.

[0006] A second object of the present invention is to provide a seat element capable of detecting rotations of the occupant's torso or pelvis. In particular, rotations around a vertical axis. Summary of the invention

[0007] The present invention relates to a seat element, in particular a seat for a motor vehicle; the seat element comprising a mattress and upholstery arranged around the mattress, the seat element extending in a transverse direction and a longitudinal direction; the seat element comprising two edges lateral longitudinals; a central longitudinal plane extending between and midway between the two lateral longitudinal edges; a first side of the seat element being situated on one side of the central longitudinal plane, a second side being situated on the other side of the central longitudinal plane; the seat element comprising a first coplanar interdigitated electrode capacitive sensor arranged on the first side and a second coplanar interdigitated electrode capacitive sensor arranged on the second side; the second capacitive sensor being separated from the first capacitive sensor in a longitudinal direction by a first distance of between 30 millimeters and 50 millimeters and preferably by a first distance of 40 millimeters.Advantageously, when the second and third capacitive sensors are separated by this initial distance, the capacitance values ​​they generate make it possible to detect the torsional positions of the body regardless of the size of the seat and the morphology of the occupant.

[0008] The features described in the following paragraphs may optionally be implemented. They may be implemented independently of each other or in combination with each other: - The seat element includes a removable back cushion intended to be placed on a seat; the seat comprising a seat and a back hinged to the seat, the back having a front face suitable for receiving the back of an occupant; the removable back cushion being intended to be placed on the front face of the seat back. - The first capacitive sensor is separated from the second capacitive sensor by a second distance between 50 millimeters and 150 millimeters, preferably by a second distance equal to 80 millimeters; this second distance being measured along a transverse direction. - It further comprises a third coplanar interdigitated electrode capacitive sensor arranged on the first side of the longitudinal central plane, and the third capacitive sensor is separated from the first capacitive sensor along the longitudinal direction by a third distance between 250 millimeters and 290 millimeters, and preferably by a third distance equal to 270 millimeters. Advantageously, when the first and third capacitive sensors are separated by this distance, the capacitance values ​​that these sensors generate make it possible to detect a rounding of the seat occupant's back around a horizontal axis regardless of the size of the seat and the morphology of the seat occupant. - It further comprises a fourth coplanar interdigitated electrode capacitive sensor arranged on the second side of the longitudinal central plane; the fourth capacitive sensor being separated from the third capacitive sensor along the longitudinal direction by a fourth distance between 30 millimeters and 50 millimeters, and preferably by a fourth distance equal to 40 millimeters. -The fourth capacitive sensor is separated from the third capacitive sensor by a fifth distance between 50 millimeters and 150 millimeters, and preferably by a fifth distance equal to 80 millimeters; said fifth distance being measured along a transverse direction. The removable seat cushion is intended to be mounted on a seat having a headrest and at least one rod fixed to the backrest and the headrest, and in which the seat cushion has at least one opening for receiving at least one headrest fixing rod, the seat cushion having a front edge bordering the opening and extending over the front face of the seat back, and the first capacitive sensor is located at one-sixth distance from said front edge; the sixth distance being between 200 and 300 millimeters, and preferably the sixth distance being 250 millimeters. Advantageously, this positioning of the first capacitive sensor makes it possible to detect a movement or a more pronounced pressure of the shoulder blade of a seat occupant. - The removable seat cushion is intended to be mounted on the backrest having an upper face, and wherein the removable seat cushion has a support part intended to come to rest against the upper face of the backrest, the support part having a front end intended to be arranged between the upper face and the front face of the backrest, and wherein the first capacitive sensor is located at a distance of one-sixth from the front end of said support part; the sixth distance being between 200 and 220 millimeters, and preferably the sixth distance being equal to 210 millimeters. - The seat element includes a removable seat cushion intended to be placed on a seat; the seat comprising a seat and a backrest articulated to the seat, the seat having a seating face suitable for receiving an occupant; the removable seat cushion being intended to be placed on the seating face of the seat. - The seat element comprises a third coplanar interdigitated electrode capacitive sensor arranged on the first side and a fourth coplanar interdigitated electrode capacitive sensor arranged on the second side; the third capacitive sensor being separated from the fourth capacitive sensor in a longitudinal direction by a fourth distance between 30 millimeters and 50 millimeters and, preferably, by a fourth distance D4' equal to 40 millimeters.

[0009] The invention also relates to a seat, in particular a motor vehicle seat, said seat comprising a seat and a backrest hinged to the seat, the backrest having a front face, a rear face and a top face; the seat comprising a seat element having at least one of the characteristics mentioned above, and the first capacitive sensor is located at a sixth distance between 200 and 300 millimeters, and preferably at a sixth distance of 250 millimeters from the edge located between the top face and the front face, when the seat element is attached to the seat. Brief description of the figures

[0010] [Fig-1] is a perspective view of a seat on which rests a seat element according to a first embodiment;

[0011] [Fig.2] is a schematic cross-sectional view of a seat element according to the first embodiment, the section being made in a median plane of the seat element;

[0012] [Fig.3] is a schematic front view of an example of a capacitive sensor intended to be arranged in the seat element according to the invention;

[0013] [Fig.4] is a schematic cross-sectional view of a first variant of the seat element according to the first embodiment; and

[0014] [Fig.5] is a perspective view of a seat on which rests a second variant of the seat element according to the first embodiment;

[0015] [Fig.6] is a top view of a seat equipped with a seat element according to a second embodiment of the invention. Detailed description of the invention

[0016] In the following description, spatial positioning indications such as front, rear, top, bottom, upper, lower, horizontal, vertical, etc., are to be interpreted in relation to the usual position of a seat in a vehicle and the usual position of a removable cushion placed on the seat. The front direction refers to the direction of a vehicle moving forward. These usual positions are illustrated in [Fig. 1]. In particular, the front face of a seat back is the face against which the back of a seat occupant rests.

[0017] Figure 1 shows an example of a seat 2 according to the present invention. The seat 2 comprises a seat 4, a backrest 6 articulated to the seat and a headrest 12 fixed to the backrest by rods 14.

[0018] The seat 4 has a seat face 5 intended to receive the buttocks and part of the legs of a seat occupant.

[0019] The backrest 6 further comprises a front face 8, a rear face 9, two side faces 10, a lower face 11 articulated to the seat and an upper face 13 opposite the lower face.

[0020] A seat element according to a first embodiment of the invention is a removable backrest cushion 16, that is to say, the removable cushion is intended to be placed on the front face 8 of the seat back. This removable cushion 16 comprises at least one mattress 18 and a cover 19 arranged around the mattress. The mattress 18 comprises a layer of foam or quilting. The mattress may also comprise several layers of foam or quilting.

[0021] With reference to [Fig. 2], the removable cushion 16 extends along a longitudinal direction X and a transverse direction Y perpendicular to the longitudinal direction X. The removable cushion 16 has an upper transverse edge 20 and a lower transverse edge 22 extending along the transverse direction Y. The removable cushion 16 further has two lateral longitudinal edges 24, 26 extending along the longitudinal direction X.

[0022] In the embodiment shown in Figures 1 and 2, the removable cushion 16 further comprises two openings 28 or notches for receiving the rods 14 of the headrest. The openings have a front edge 30 located on the side of the front face 8 of the backrest and a rear edge 31 located on the side of the rear face 9 of the backrest, when the removable cushion 16 is mounted on the seat back.

[0023] For the purposes of this description, a central longitudinal plane (X,Z) is defined as perpendicular to the median plane of the cushion. It intersects the center of the removable cushion along a central line XL. The central line XI is parallel to the lateral longitudinal edges 24, 26. The central line XI is located at the center, that is, midway between the two lateral longitudinal edges 24, 26. For the purposes of this description, the side of the cushion located on one side of the central longitudinal plane (X,Z), for example on the left, is called the "first side 32" of the cushion, and the side of the cushion located on the other side of the central longitudinal plane, for example on the right, is called the "second side 34".

[0024] Fig. 2 schematically represents an example of a cross-sectional view of the removable cushion 16 according to a first embodiment of the invention.

[0025] The removable cushion 16 includes a first capacitive sensor 36 with coplanar interdigitated electrodes and a second capacitive sensor 42 with coplanar interdigitated electrodes, hereinafter referred to as the first and second capacitive sensors.

[0026] The first capacitive sensor 36 and the second capacitive sensor 42 are arranged between the cover 19 and the mattress when the mattress has a foam layer. Alternatively, the first capacitive sensor 36 and the second capacitive sensor 42 are arranged between two foam layers when the mattress has two foam layers. The first capacitive sensor and the second capacitive sensor extend along the transverse direction Y. They are suitable for measuring capacitance values.

[0027] The first capacitive sensor 36 is arranged on the first side 32 of the longitudinal central plane (X, Z). The second capacitive sensor 42 is arranged on the second side 34 of the longitudinal central plane (X, Z).

[0028] The first capacitive sensor 36 is separated from the second capacitive sensor 42 along a longitudinal direction X by a first distance DI of between 30 millimeters and 50 millimeters. Preferably, the first distance DI is equal to 40 millimeters. limmeters. In the embodiment shown, the first capacitive sensor 36 is closer to the upper transverse edge 20 of the cushion than the second capacitive sensor 42. Advantageously, when the first and second capacitive sensors are separated by this initial distance Dl, the capacitance values ​​they generate allow for the detection of body torsion positions regardless of seat size or occupant's body shape. A "torsion position" is defined as a pivoting of the body around a vertical axis located at the level of the spine and any resulting poor pelvic posture. Such a torsion can, for example, result from a driver holding the steering wheel with only one hand or from a person sitting in an office chair crossing one leg over the other. The offset between the positioning of the first and second capacitive sensors enables highly effective detection of poor posture when the removable cushion is used on seat backs of varying sizes and for individuals with different body shapes.

[0029] Preferably, the first capacitive sensor 36 is separated along the transverse direction Y from the second capacitive sensor 42 by a second distance D2. The second distance is between 50 and 150 millimeters. Preferably, the second distance is equal to 80 millimeters.

[0030] The ends of the capacitive sensors on the center side of the seat cushion are used to perform measurements along the longitudinal Y direction, as seen in [Fig.2],

[0031] Preferably, the seat cushion further comprises a third coplanar capacitive sensor 38 with interdigitated electrodes arranged between the cover 19 and the mattress or between two layers of mattress foam. The third capacitive sensor 38 is located on the first side 32 of the longitudinal central plane (X, Z). Preferably, the first capacitive sensor 36 and the third capacitive sensor 38 are aligned with each other along a first straight line X2 directed along the longitudinal direction X.

[0032] Preferably, the third capacitive sensor 38 is separated from the first capacitive sensor 36 along the longitudinal direction X by a third distance D3. The third distance D3 is between 250 millimeters and 290 millimeters. Preferably, the third distance D3 is equal to 270 millimeters. The midpoint of the capacitive sensors is used to perform the distance measurements along the longitudinal direction X in the present application, as shown in [Fig. 2].

[0033] When the first and third capacitive sensors are separated by this distance, the capacitance values ​​that these sensors generate make it possible to detect a rounding of the seat occupant's back around a horizontal axis regardless of the The dimensions of the seat and the morphology of the seat occupant. Morphology refers to the general shape of a person. It includes their height and width.

[0034] Advantageously, this positioning of the third capacitive sensor 38 makes it possible to detect a movement or a more pronounced pressure of a part of the pelvis of an occupant of the seat.

[0035] Preferably, the removable cushion 16 comprises a fourth coplanar capacitive sensor 40 with interdigitated electrodes arranged between the cover 19 and the mattress or between two layers of mattress foam. The fourth capacitive sensor 40 is located on the second side 34 of the longitudinal central plane (X, Z). Preferably, the fourth capacitive sensor 40 is positioned away from the third capacitive sensor 38 along a longitudinal direction X by a distance D4 between 30 and 50 millimeters. Preferably, this fourth distance D4 is 40 millimeters. In the embodiment shown in [Fig. 2] by way of example, the fourth capacitive sensor 40 is closer to the lower transverse edge 22 of the cushion than the third capacitive sensor 38. Preferably, the fourth capacitive sensor 40 and the second capacitive sensor 42 are aligned along a straight line X3 which extends in a longitudinal direction X. Preferably, the fourth capacitive sensor 40 is separated from the second capacitive sensor 42, in a longitudinal direction X, by the third distance D3.

[0036] Preferably, the fourth capacitive sensor 40 is located, along the transverse direction Y, from the third capacitive sensor 38 by a fifth distance D5. This fifth distance is between 50 millimeters and 150 millimeters. Preferably, the fifth distance is 80 millimeters.

[0037] Preferably also, the fifth distance D5 is equal to the second distance D2.

[0038] In the embodiment shown, the first capacitive sensor 36 is closer to the upper transverse edge 20 than the second capacitive sensor 42. The first capacitive sensor 36 is located at a sixth distance D6 between 200 and 300 millimeters from the front edge 30 of the opening 28 of the cushion. Preferably, the sixth distance D6 is 250 millimeters. This positioning of the first capacitive sensor 36 makes it possible to detect a movement or a more pronounced pressure on the shoulder blade of a seat occupant.

[0039] Preferably, the four capacitive sensors are identical. An example of the first capacitive sensor 36 suitable for arrangement in the removable cushion 16 has been shown in [Fig.3].

[0040] The first capacitive sensor 36 comprises a first electrode 44 and a second electrode 46 similar to the first electrode. Each electrode comprises a rod and The fingers are attached to the stem. They extend perpendicularly to the stem and are spaced apart in a comb-like configuration. The second electrode is positioned relative to the first electrode such that the fingers of the second electrode are interposed between the fingers of the first electrode. An example of the dimensions of the stems, fingers, and the spacing between the stems and fingers of a capacitive sensor that can be arranged in the removable cushion is described in patent application FR 3 126 776.

[0041] The first electrode 44 is connected to a voltage source via an electrical connecting wire 48. The voltage source generates a voltage of, for example, 5 volts. The second electrode 46 is connected to ground via an electrical connecting wire 48.

[0042] The first capacitive sensor 36, the second capacitive sensor 42, the third capacitive sensor 38, the fourth capacitive sensor 40 and the electrical connection wires 48 are arranged on a flexible support 50. The flexible support 50 is fixed against a layer of foam or padding.

[0043] The removable cushion 16 may include a controller 52. The controller 52 may be disposed in a bag formed at one end of the cushion. The first and second electrodes of the capacitive sensors 36, 38, 40, 42 are connected to the controller 52 via the electrical connection wires 48.

[0044] The controller is configured to periodically receive capacitance values ​​from the capacitive sensors. The controller is configured to detect a rotation of a body part, in particular a part of the torso, of a seat occupant leaning against the seat cushion, based on the received capacitance values.

[0045] The controller 52 may be a programmable device that uses specific software or an ASIC. The controller includes memory and executable code for implementing a method of detecting rotation of a portion of a seat occupant's torso based on capacitance values ​​received from the capacitive sensors described above. The memory includes random access memory (RAM) and read-only memory (ROM). The memory may include executable code for implementing a method of detecting rotation of a portion of a seat occupant's torso as described in the patent application published on August 26, 2022, in the applicant's name under number FR 3120124, as well as several ranges of capacitance value variation as described in that patent application. These capacitance value ranges may be predefined during a learning phase.

[0046] The removable cushion 16 may include comfort features 54 arranged in the cushion between the cover 19 and a layer of foam or between two layers of foam of the mattress. The comfort features 54 include, for example, a vibrating equipment or pneumatic equipment to perform a massage function, a ventilation actuator and heating equipment.

[0047] The comfort equipment 54 is connected to the controller 52. The controller 52 controls the operation of the comfort equipment on command from the seat occupant or when it detects a bad positioning of the seat occupant.

[0048] Eight comfort features 54 have been shown in [Fig.2]. Alternatively, the removable cushion includes a different number of comfort features.

[0049] Alternatively, the removable cushion 16 does not include a controller. The electrical connection wires 48 are connected to a connector intended to connect to a seat electrical cable harness.

[0050] Figure 4 shows a first variant of the seat element according to the first embodiment. According to this first variant, the seat element comprises only the first capacitive sensor 36 and the second capacitive sensor 42. The first capacitive sensor 36 is separated from the second capacitive sensor 42 along a longitudinal direction X by the first distance DI. In the embodiment shown as an example in Figure 4, the first capacitive sensor 36 and the second capacitive sensor 42 are located in an upper part of the backrest. Alternatively, the first capacitive sensor and the second capacitive sensor are located in a lower part of the backrest. They are then situated at the positions of the third capacitive sensor 38 and the fourth capacitive sensor 40.

[0051] Alternatively, the removable cushion is suitable for covering both the front face 8 of the backrest and the seat face 5 of the seat and the capacitive sensors are arranged only on the part of the cushion intended to come into contact with the backrest of the seat.

[0052] Figure 5 shows a second variant of the seat element according to the first embodiment. According to this first variant, the seat element is a removable back cushion 56 identical or similar to the removable cushion 16 according to the first embodiment, except that the removable cushion does not have openings 28 or cutouts. It is placed on the upper surface 13 of the seat. It is attached to the backrest, for example, by fastening cords.

[0053] The removable cushion 56 includes a support portion 60 intended to bear against the upper surface 13 of the seat. This support portion 60 is in the form of a transverse band of the mattress. The support portion 60 includes a front end 62 intended to be arranged between the upper surface 13 and the front surface 8 of the backrest. In this embodiment, the first capacitive sensor 36 is located at a sixth distance D6 between 200 and 300 millimeters from the front end 62 of the support portion 60. Preferably, the sixth distance D6 is located 250 millimeters from the front end 62 of the support portion 60.

[0054] The other technical elements of the removable cushion according to this second variant are identical to the technical elements of the removable cushion according to the first embodiment and will not be described again. For the sake of simplicity, [Fig. 5] represents only the first capacitive sensor, but the removable cushion 56 comprises two, three, or four capacitive sensors.

[0055] Figure 6 represents a seat element according to a second embodiment. This seat element is a removable seat cushion 66, meaning that the removable cushion is intended to be placed on the seating surface 5 of the seat. This removable cushion comprises at least one mattress 18 and a cover 19 arranged around the mattress. The mattress 18 comprises a layer of foam or padding. The mattress may also comprise several layers of foam or padding.

[0056] The removable seat cushion 66 is defined with respect to a new reference frame (X', Y') illustrated in [Fig. 6]. The removable seat cushion 66 extends along a longitudinal direction X' and a transverse direction Y' perpendicular to the longitudinal direction X'. The removable cushion has a front transverse edge 69 and a rear transverse edge 70 extending along the transverse direction Y. The removable cushion 16 further has two lateral longitudinal edges 71, 73 extending along the longitudinal direction X'.

[0057] As with the seat element according to the first embodiment, a central longitudinal plane (X',Z') is defined, perpendicular to the median plane of the seat cushion. The central longitudinal plane (X',Z') is not shown. It intersects the center of the seat cushion 66 along a central line X'1. The central line X'1 is parallel to the lateral longitudinal edges 71, 73. The central line X'1 is located at the center, that is, midway between the two lateral longitudinal edges 71, 73 of the seat cushion. For the purposes of this description, the side of the cushion located on one side of the central line X'1, for example on the left, is called the "first side 72" of the cushion, and the side of the cushion located on the other side of the central line X'1, for example on the right, is called the "second side 74".

[0058] Preferably, the removable seat cushion 66 comprises a first capacitive sensor 76 with coplanar interdigitated electrodes and a second capacitive sensor 82 with coplanar interdigitated electrodes, hereinafter referred to as the first and second capacitive sensors.

[0059] The first capacitive sensor and the second capacitive sensor are arranged between the mattress 18 and the cover 19. The first capacitive sensor and the second capacitive sensor extend along the transverse direction Y. They are suitable for measuring capacitance values. The first capacitive sensor 76 is located on the first side 72 of the removable seat cushion. The second capacitive sensor 82 is located on the second side 74 of the central line X' 1 of the cushion.

[0060] The first capacitive sensor 76 is separated from the second capacitive sensor 42 according to the longitudinal direction X' of a first distance D' 1. The first distance D' 1 is between 30 millimeters and 50 millimeters. Preferably, the first distance D' 1 is equal to 40 millimeters. Preferably, the seat cushion 66 comprises a third capacitive sensor 78 with coplanar interdigitated electrodes and a fourth capacitive sensor 80 with coplanar interdigitated electrodes arranged between the cover 19 and a layer of mattress foam or between two layers of mattress foam. The third capacitive sensor 78 is located on the first side 72 of the central line X' 1. The fourth capacitive sensor 80 is located on the second side 74 of the central line ZI. The third capacitive sensor is separated from the fourth capacitive sensor along the longitudinal direction X' by a fourth distance D'4 of between 30 millimeters and 50 millimeters. Preferably, the fourth distance D'4 is equal to 40 millimeters.

[0061] The technical elements of the seat element according to the second embodiment that are identical or similar to the technical elements of the seat element according to the first embodiment bear the same reference numerals and will not be described a second time.

Claims

Demands

1. Seat element (16,56;66), in particular a seat element of a motor vehicle seat; the seat element comprising a mattress (18) and a cover (19) arranged around the mattress, the seat element extending in a transverse direction (Y; Y') and a longitudinal direction (X; X'); the seat element comprising two lateral longitudinal edges (24,26;71,73); a central longitudinal plane ((X,Z); (X',Z')) extending between and midway between the two lateral longitudinal edges; a first side (32;72) of the seat element being located on one side of the central longitudinal plane, a second side (34;74) being located on the other side of the central longitudinal plane; the seat element comprising a first capacitive sensor (36;76) with coplanar interdigitated electrodes arranged on the first side (32;72) and a second capacitive sensor (42;82) with coplanar interdigitated electrodes arranged on the second side (34;74); the second capacitive sensor (42;82) being distant from the first capacitive sensor (36;76) along a longitudinal direction (X;X') of a first distance (DI;D1') between 30 millimeters and 50 millimeters and preferably of a first distance (D1;D1') equal to 40 millimeters.;

2. Seat element (16,56) according to claim 1, wherein the seat element comprises a removable back cushion (16) intended to be placed on a seat; the seat (2) comprising a seat (4) and a backrest (6) articulated to the seat, the backrest (6) having a front face (8) adapted to receive the back of an occupant; the removable back cushion being intended to be placed on the front face (8) of the backrest of the seat (2).

3. Seat element (16,56) according to claim 2, wherein the first capacitive sensor (36) is separated from the second capacitive sensor (42) by a second distance (D2) between 50 millimeters and 150 millimeters, preferably a second distance equal to 80 millimeters; this second distance (D2) being measured along a transverse direction (Y).

4. Seat element (16,56) according to any one of claims 2 and 3, further comprising a third coplanar interdigitated electrode capacitive sensor (38) arranged on the first side (32) of the longitudinal central plane, and wherein the third capacitive sensor (38) is separated from the first capacitive sensor (36) along the longitudinal direction by a third distance (D3) of between 250 millimeters and 290 millimeters. lines, and preferably a third distance equal to 270 millimeters.

5. Seat element (16,56) according to claim 4, further comprising a fourth coplanar interdigitated electrode capacitive sensor (40) arranged on the second side (34) of the longitudinal central plane (X,Z); the fourth capacitive sensor (40) being separated from the third capacitive sensor (38) along the longitudinal direction (X) by a fourth distance (D4) between 30 millimeters and 50 millimeters, and preferably by a fourth distance (D4) equal to 40 millimeters.

6. Seat element (16,56) according to the combination of claims 4 and 5, wherein the fourth capacitive sensor (40) is separated from the third capacitive sensor (38) by a fifth distance (D5) of between 50 millimeters and 150 millimeters, and preferably by a fifth distance of 80 millimeters; said fifth distance (D5) being measured along a transverse direction (Y).

7. Seat element (16,56) according to any one of claims 2 to 6, wherein the removable seat cushion (16) is intended to be mounted on a seat (2) having a headrest (12) and at least one rod (14) fixed to the backrest and the headrest, and wherein the seat cushion (16) has at least one opening (28) for receiving at least one rod (14) for fixing the headrest, the seat cushion (16) having a front edge (30) bordering the opening (28) and extending over the front face (8) of the seat back, and wherein the first capacitive sensor (36) is located at a sixth distance (D6) from said front edge (30); the sixth distance being between 200 and 300 millimeters, and preferably the sixth distance (D6) being equal to 250 millimeters.

8. Seat element (56) according to any one of claims 2 to 6, wherein the removable seat cushion (56) is intended to be mounted on the backrest (6) having an upper face (13), and wherein the removable seat cushion (56) has a support portion (60) intended to bear against the upper face (13) of the backrest, the support portion (60) having a front end (62) intended to be arranged between the upper face (13) and the front face (8) of the backrest, and wherein the first capacitive sensor (36) is located at a sixth distance (D6) from the front end (62) of said support portion; the sixth distance being between 200 and 220 millimeters, and preferably the sixth distance (D6) being equal to 210 millimeters.

9. Seat element (66) according to claim 1, wherein the element of seat (66) includes a removable seat cushion intended to be placed on a seat; the seat (2) comprising a seat (4) and a backrest (6) articulated to the seat, the seat (4) having a seating face (5) suitable for receiving an occupant; the removable seat cushion being intended to be placed on the seating face (5) of the seat of the seat (2).

10. Seating element (66) according to claim 9, wherein the seating element comprises a third coplanar interdigitated electrode capacitive sensor (78) arranged on the first side (72) and a fourth coplanar interdigitated electrode capacitive sensor (80) arranged on the second side (74); the third capacitive sensor being separated from the fourth capacitive sensor along a longitudinal direction (X') by a fourth distance (D4') of between 30 millimeters and 50 millimeters and, preferably, by a fourth distance (D4') of 40 millimeters.

11. Seat (2) in particular motor vehicle seat, said seat (2) comprising a seat (4) and a backrest (6) articulated to the seat, the backrest (6) having a front face (8), a rear face (9) and an upper face (13); the seat comprising a seat element (16, 56) according to any one of claims 2 to 9, and in which the first capacitive sensor (36) is located at a sixth distance (D6) of between 200 and 300 millimeters, and preferably at a sixth distance (D6) of 250 millimeters from the edge located between the upper face (13) and the front face (8), when the seat element is fixed to the seat.

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