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 a motor vehicle 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 which can be attached and placed on a backrest or on a seat base. State of the prior art

[0002] Some people adopt an inappropriate sitting position on a seat or chair such as an office chair, a medical chair or a vehicle seat. This inappropriate 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 make twisting movements of the spine 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 with a bad posture detection function. For cars that do not have this function, a seat element such as a removable cushion with this function may be mounted on the seat.

[0004] This seat element must not only be suitable for people of different body shapes but also suitable 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 aim of the present invention is to propose a seat element capable of detecting the poor postures of seat occupants having 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 of a seat, in particular of a motor vehicle seat; the seat element comprising a mattress and a covering arranged around the mattress, the seat element extending in a transverse direction and a longitudinal direction; the seat element comprising two edges longitudinal lateral edges; a longitudinal central plane extending between and midway between the two lateral longitudinal edges; a first side of the seat element being located on one side of the longitudinal central plane, a second side being located on the other side of the longitudinal central plane; the seat element comprising a first capacitive sensor with coplanar interdigital electrodes arranged on the first side and a second capacitive sensor with coplanar interdigital electrodes arranged on the second side; the second capacitive sensor being distant 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 equal to 40 millimeters.Advantageously, when the second and third capacitive sensors are separated by this first distance, the capacitance values ​​that they generate make it possible to detect the torsion positions of the body regardless of the size of the seat and the morphology of the occupant.

[0008] The features set out in the following paragraphs may optionally be implemented. They may be implemented independently of one another or in combination with one another: - The seat element comprises 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 back of the seat. - The first capacitive sensor is separated from the second capacitive sensor by a second distance of between 50 millimeters and 150 millimeters, preferably by a second distance equal to 80 millimeters; this second distance being measured in a transverse direction. - It further comprises a third capacitive sensor with coplanar interdigitated electrodes arranged on the first side of the longitudinal central plane, and the third capacitive sensor is distant from the first capacitive sensor in the longitudinal direction by a third distance of 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 back of the occupant of the seat around a horizontal axis regardless of the size of the seat and the morphology of the occupant of the seat. - It further comprises a fourth capacitive sensor with coplanar interdigitated electrodes arranged on the second side of the longitudinal central plane; the fourth capacitive sensor being distant from the third capacitive sensor in the longitudinal direction by a fourth distance of between 30 millimeters and 50 millimeters, and preferably by a fourth distance equal to 40 millimeters. -The fourth capacitive sensor is distant from the third capacitive sensor by a fifth distance of between 50 millimeters and 150 millimeters, and preferably by a fifth distance equal to 80 millimeters; said fifth distance being measured in a transverse direction. The removable seat cushion is intended to be mounted on a seat comprising a headrest and at least one rod fixed to the backrest and to the headrest, and in which the seat cushion comprises at least one opening intended to receive the at least one rod for fixing the headrest, the seat cushion having a front edge bordering the opening and extending on the front face of the seat backrest, and the first capacitive sensor is located at a sixth distance from said front edge; the sixth distance being between 200 and 300 millimeters, and preferably the sixth distance being equal to 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 comprises a support portion intended to bear against the upper face of the backrest, the support portion comprising 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 sixth distance from the front end of said support portion; the sixth distance being between 200 and 220 millimeters, and preferably the sixth distance being equal to 210 millimeters. - The seat element comprises 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 seat face suitable for receiving an occupant; the removable seat cushion being intended to be placed on the seat face of the seat of the seat. - The seat element comprises a third capacitive sensor with coplanar interdigital electrodes arranged on the first side and a fourth capacitive sensor with coplanar interdigital electrodes arranged on the second side; the third capacitive sensor being distant from the fourth capacitive sensor in a longitudinal direction by a fourth distance of 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 articulated to the seat, the backrest having a front face, a rear face and an upper 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 of between 200 and 300 millimeters, and preferably at a sixth distance of 250 millimeters from the edge located between the upper face and the front face, when the seat element is fixed to the seat. Brief description of the figures

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

[0011] [Fig.2] is a schematic 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 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, the spatial positioning indications such as front, rear, top, bottom, upper, lower, horizontal, vertical etc. are to be interpreted according to the usual position of use of a seat in a vehicle as well as the usual position of a removable cushion arranged on the seat. The forward direction being the direction of a vehicle moving forward. These usual positions are illustrated in [Fig.l]. In particular, the front face of a backrest is the face on which the back of an occupant of the seat rests.

[0017] [Fig. 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 comprises a seat face 5 intended to receive the buttocks and part of the legs of an occupant of the seat.

[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 back cushion 16, that is to say that 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 covering 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.

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

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

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

[0025] The removable cushion 16 comprises a first capacitive sensor 36 with coplanar interdigital electrodes and a second capacitive sensor 42 with coplanar interdigital electrodes, hereinafter called first and second capacitive sensors.

[0026] The first capacitive sensor 36 and the second capacitive sensor 42 are arranged between the covering 19 and the mattress when the mattress comprises a layer of foam. Alternatively, the first capacitive sensor 36 and the second capacitive sensor 42 are arranged between two layers of foam when the mattress comprises two layers of foam. The first capacitive sensor and the second capacitive sensor extend in 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 distant from the second capacitive sensor 42 in 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. meters. In the embodiment shown, the first capacitive sensor 36 is closer to the upper transverse edge 20 of the pad than the second capacitive sensor 42. Advantageously, when the first and second capacitive sensors are separated by this first distance D1, the capacitance values ​​that they generate make it possible to detect the torsion positions of the body regardless of the size of the seat and the morphology of the occupant. A "torsion position" is a pivoting of the body around a vertical axis located at the level of the spine and any resulting poor posture of the pelvis. Such a torsion can, for example, result from the fact that a driver holds the steering wheel with only one hand or that a person sitting on an office chair crosses one leg over the other. The offset between the positioning of the first capacitive sensor and the positioning of the second capacitive sensor allows very effective detection of poor posture, when the removable cushion is arranged on seat backs of different sizes and for people with different morphologies.

[0029] Preferably, the first capacitive sensor 36 is spaced in 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 carry out the measurements along the longitudinal direction Y, as seen in [Fig.2],

[0031] Preferably, the seat cushion further comprises a third capacitive sensor 38 with coplanar interdigital electrodes arranged between the covering 19 and the mattress or between two layers of foam of the mattress. 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 in the longitudinal direction X.

[0032] Preferably, the third capacitive sensor 38 is spaced from the first capacitive sensor 36 in 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 middle of the capacitive sensors is used to carry out the distance measurements in the longitudinal direction X in the present application as visible 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 back of the occupant of the seat around a horizontal axis regardless of the seat size and the morphology of the seat occupant. Morphology refers to the general shape of people. It includes a person's 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 capacitive sensor 40 with coplanar interdigital electrodes arranged between the covering 19 and the mattress or between two layers of foam of the mattress. 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 distant from the third capacitive sensor 38 in a longitudinal direction X, by a fourth distance D4 of between 30 millimeters and 50 millimeters. Preferably, the fourth distance D4 is equal to 40 millimeters. In the embodiment shown in [Fig.2] as an 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 distant from the second capacitive sensor 42, in a longitudinal direction X, by the third distance D3.

[0036] Preferably, the fourth capacitive sensor 40 is spaced in the transverse direction Y from the third capacitive sensor 38 by a fifth distance D5. The fifth distance is between 50 millimeters and 150 millimeters. Preferably, the fifth distance is equal to 80 millimeters.

[0037] Also preferably, 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 of between 200 and 300 millimeters from the front edge 30 of the opening 28 of the cushion. Preferably, the sixth distance D6 is equal to 250 millimeters. This positioning of the first capacitive sensor 36 makes it possible to detect a movement or a more pronounced pressure of the shoulder blade of an occupant of the seat.

[0039] Preferably, the four capacitive sensors are identical. An example of the first capacitive sensor 36 suitable for being arranged 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 fingers integral with the rod. The fingers extend perpendicular to the rod. The fingers are spaced apart from each other in a comb-shaped 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 rods, fingers, and spacings between the rods and fingers of a capacitive sensor that can be arranged in the removable pad is described in the patent application published under number FR 3 126 776.

[0041] The first electrode 44 is connected to a voltage source via an electrical connection wire 48. The voltage source generates a voltage of, for example, 5 volts. The second electrode 46 is connected to a ground via an electrical connection 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 electrode and the second electrode 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 trunk part, of a seat occupant leaning against the seat cushion from the received capacitance values.

[0045] The controller 52 may be a programmable device that uses software or a specific integrated circuit (ASIC). The controller comprises a memory and executable code for implementing a method for detecting a rotation of a portion of the trunk of a seat occupant from the capacitance values ​​received from the capacitive sensors previously described. The memory comprises a random access memory, denoted RAM, and a read only memory denoted ROM. The memory may comprise executable code for implementing a method for detecting a rotation of a portion of the trunk of a seat occupant as described in the patent application published on August 26, 2022 in the name of the applicant under the number FR 3120124, as well as several ranges of variation of capacitance values ​​as described in this patent application. Ranges of variation of capacitance values ​​may be predefined during a learning phase.

[0046] The removable cushion 16 may include comfort equipment 54 arranged in the cushion between the covering 19 and a layer of foam or between two layers of foam of the mattress. The comfort equipment 54 comprises, 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 upon command from the seat occupant or when it detects poor positioning of the seat occupant.

[0048] Eight comfort features 54 have been shown in [Fig.2]. Alternatively, the removable cushion comprises 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 for connecting to a seat electrical wire harness.

[0050] [Fig. 4] represents a first variant of the seat element according to the first embodiment. According to this first variant, the seat element only comprises the first capacitive sensor 36 and the second capacitive sensor 42. The first capacitive sensor 36 is distant from the second capacitive sensor 42 in a longitudinal direction X, by the first distance DI. In the embodiment shown as an example in [Fig. 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 located at the positions of the third capacitive sensor 38 and the fourth capacitive sensor 40.

[0051] As a variant, the removable cushion is suitable for covering both the front face 8 of the backrest and the seat face 5 of the seat base and the capacitive sensors are arranged only on the part of the cushion intended to come to bear against the backrest of the seat.

[0052] [Fig. 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 notches. It is placed on the upper face 13 of the seat. It is fixed to the back for example by attachment cords.

[0053] The removable cushion 56 comprises a support portion 60 intended to bear against the upper face 13 of the seat. This support portion 60 has the shape of a transverse strip of the mattress. The support portion 60 comprises a front end 62 intended to be arranged between the upper face 13 and the front face 8 of the backrest. In this variant, the first capacitive sensor 36 is located at a sixth distance D6 of 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 reasons of simplification, [Fig.5] represents only the first capacitive sensor but the removable cushion 56 comprises two, three or four capacitive sensors.

[0055] [Fig. 6] shows a seat element according to a second embodiment. This seat element is a removable seat cushion 66, that is to say that the removable cushion is intended to be placed on the seat face 5 of the seat of the seat. This removable cushion comprises at least one mattress 18 and a covering 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 relative to a new reference (X', Y') illustrated in [Fig. 6]. The removable seat cushion 66 extends in 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 in the transverse direction Y. The removable cushion 16 further has two lateral longitudinal edges 71, 73 extending in the longitudinal direction X'.

[0057] In the same way as for the seat element according to the first embodiment, a longitudinal central plane (X',Z') is defined perpendicular to the median plane of the seat cushion. The longitudinal central plane (X',Z') is not shown. It intersects the center of the seat cushion 66 along a central straight line X' 1. The central straight line X' 1 is parallel to the lateral longitudinal edges 71, 73. The central straight line X' 1 is located in the center, that is to say 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 straight line X' 1, for example on the left, is called "first side 72" of the cushion, and the side of the cushion located on the other side of the central straight line X' 1, for example on the right, is called "second side 74".

[0058] Preferably, the removable seat cushion 66 comprises a first capacitive sensor 76 with coplanar interdigital electrodes and a second capacitive sensor 82 with coplanar interdigital 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 covering 19. The first capacitive sensor and the second capacitive sensor extend in the transverse direction Y. They are suitable for measuring capacitance values. The first capacitive sensor 76 is arranged on the first side 72 of the removable seat cushion. The second capacitive sensor 82 is arranged on the second side 74 of the central line X' 1 of the cushion.

[0060] The first capacitive sensor 76 is distant from the second capacitive sensor 42 according to the longitudinal direction X' by 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 interdigital electrodes and a fourth capacitive sensor 80 with coplanar interdigital electrodes arranged between the covering 19 and a foam layer of the mattress or between two foam layers of the mattress. 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 spaced from the fourth capacitive sensor in 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 which are identical or similar to the technical elements of the seat element according to the first embodiment bear the same references and will not be described a second time.

Claims

Claims

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 covering (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 longitudinal central 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 longitudinal central plane, a second side (34; 74) being located on the other side of the longitudinal central plane; the seat element comprising a first capacitive sensor (36; 76) with coplanar interdigital electrodes arranged on the first side (32; 72) and a second capacitive sensor (42; 82) with coplanar interdigital electrodes arranged on the second side (34; 74); the second capacitive sensor (42;82) being distant from the first capacitive sensor (36; 76) in a longitudinal direction (X; X') by a first distance (DI; D1') of between 30 millimeters and 50 millimeters and preferably by a first distance (D1; D1') equal to 40 millimeters.;

2. A 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 back (6) articulated to the seat, the back (6) having a front face (8) suitable for receiving the back of an occupant; the removable back cushion being intended to be placed on the front face (8) of the back of the seat (2).

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

4. Seat element (16, 56) according to any one of claims 2 and 3, which further comprises a third capacitive sensor (38) with coplanar interdigitated electrodes arranged on the first side (32) of the longitudinal central plane, and in which the third capacitive sensor (38) is distant from the first capacitive sensor (36) in the longitudinal direction by a third distance (D3) of between 250 millimeters and 290 millimeters. meters, and preferably a third distance equal to 270 millimeters.

5. Seat element (16, 56) according to claim 4, which further comprises a fourth capacitive sensor (40) with coplanar interdigitated electrodes arranged on the second side (34) of the longitudinal central plane (X, Z); the fourth capacitive sensor (40) being distant from the third capacitive sensor (38) in the longitudinal direction (X) by a fourth distance (D4) of 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, in which the fourth capacitive sensor (40) is distant from the third capacitive sensor (38) by a fifth distance (D5) of between 50 millimeters and 150 millimeters, and preferably by a fifth distance equal to 80 millimeters; said fifth distance (D5) being measured in a transverse direction (Y).

7. A 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) comprising a headrest (12) and at least one rod (14) fixed to the backrest and to the headrest, and wherein the seat cushion (16) comprises at least one opening (28) intended to receive the 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 seatback, 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. A 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 bearing portion (60) intended to bear against the upper face (13) of the backrest, the bearing portion (60) comprising 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 bearing portion; the sixth distance being between 200 and 220 millimeters, and preferably the sixth distance (D6) being equal to 210 millimeters.

9. A seat element (66) according to claim 1, wherein the seat element seat (66) comprises 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 seat face (5) suitable for receiving an occupant; the removable seat cushion being intended to be placed on the seat face (5) of the seat of the seat (2).

10. Seat element (66) according to claim 9, wherein the seat element comprises a third capacitive sensor (78) with coplanar interdigital electrodes arranged on the first side (72) and a fourth capacitive sensor (80) with coplanar interdigital electrodes arranged on the second side (74); the third capacitive sensor being distant from the fourth capacitive sensor in a longitudinal direction (X') by a fourth distance (D4') of between 30 millimeters and 50 millimeters and, preferably, by a fourth distance (D4') equal to 40 millimeters.

11. Seat (2) in particular a 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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