Seat element and motor vehicle seat

Abstract

The invention relates to a seat element (16) comprising a cushion (18) and a cover arranged around the cushion, the seat element comprising two longitudinal side edges (24, 26), a first side (32) of the seat element being located on one side of a longitudinal center plane and a second side (34) being located on the other side of the longitudinal center plane, the seat element comprises a first coplanar interdigital electrode capacitive sensor (36) disposed on a first side (32) and a second coplanar interdigital electrode capacitive sensor (42) disposed on a second side (34), the second capacitive sensor (42) being a first distance (D1) from the first capacitive sensor (36) in the longitudinal direction (X), the first distance (D1) being between 30 mm and 50 mm.

Description

Technical Field

[0001] The present invention relates to a seat element and a seat comprising the seat element. In particular, the present invention relates to a detachable seat cushion which can be attached to and rest on a backrest or a seat cushion. Background Art

[0002] Some people sit improperly in a chair or seat, such as an office chair, medical chair, or car seat. This improper posture can lead to back pain.

[0003] Specifically, during long drives, drivers often hunch over in their seats due to fatigue or decreased muscle tone. Some drivers twist their spines when driving with one hand or turning to their seatmates. These postures are not ergonomic and may cause back pain. Some cars may be equipped with seats with posture detection. For cars that are not equipped with this function, seat elements with this function (e.g., removable cushions) can be installed on the seats.

[0004] The seat element must not only adapt to people of different body shapes, but also to seats of different sizes. In the motor vehicle sector in particular, the removable cushion is preferably suitable for class A, class B or class C vehicle seats. SUMMARY OF THE INVENTION

[0006] A first object of the present invention is to provide a seat element which is able to detect poor postures of seat occupants of different morphologies, regardless of the size of the seat in which it is installed.

[0007] A second object of the present invention is to provide a seat element capable of detecting rotation of an occupant's torso or pelvis, in particular rotation about a vertical axis. Summary of the invention

[0008] The object of the present invention is to provide a seat element of a seat, in particular a seat element of a motor vehicle seat; the seat element includes a cushion and a cover arranged around the cushion, and the seat element extends in a transverse direction and a longitudinal direction; the seat element includes two longitudinal side edges; a longitudinal center plane extending between and in the middle of the two longitudinal side edges; a first side of the seat element is located on one side of the longitudinal center plane, and a second side thereof is located on the other side of the longitudinal center plane; the seat element includes 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 is at a first distance from the first capacitive sensor in the longitudinal direction, the first distance is between 30 mm and 50 mm, and preferably, the first distance is 40 mm.

[0009] Advantageously, when the second and third capacitive sensors are spaced at the first distance, the capacitance values ​​generated by these sensors are capable of detecting the torsional position of the body regardless of the seat size and occupant morphology.

[0010] The features disclosed in the following paragraphs can be implemented selectively. They can be implemented independently of each other or in combination with each other:

[0011] - the seat element comprises a removable backrest pad intended to be placed on a seat comprising a seat cushion and a backrest hinged on the seat cushion, the backrest having a front surface suitable for receiving the back of an occupant, the removable backrest pad intended to be placed on the front surface of the backrest of the seat.

[0012] The first capacitive sensor is at a second distance from the second capacitive sensor, the second distance being between 50 mm and 150 mm, preferably 80 mm, the second distance being measured in the transverse direction.

[0013] - It also includes a third coplanar interdigitated electrode capacitive sensor arranged on the first side of the longitudinal center plane, and the third capacitive sensor is separated from the first capacitive sensor by a third distance in the longitudinal direction, the third distance being between 250 mm and 290 mm, and preferably, the third distance is equal to 270 mm.

[0014] Advantageously, when the first and third capacitive sensors are spaced this distance apart, the capacitance values ​​produced by these sensors are capable of detecting bending of the seat occupant's back about a horizontal axis regardless of seat size and occupant morphology.

[0015] - It also includes a fourth coplanar interdigitated electrode capacitive sensor arranged on the second side of the longitudinal center plane, the fourth capacitive sensor being at a fourth distance from the third capacitive sensor in the longitudinal direction, the fourth distance being between 30 mm and 50 mm, and preferably, the fourth distance being equal to 40 mm.

[0016] The fourth capacitive sensor is at a fifth distance from the third capacitive sensor, the fifth distance being between 50 mm and 150 mm, and preferably being 80 mm, the fifth distance being measured in the transverse direction.

[0017] A removable seat cushion is intended to be mounted on a seat comprising a headrest and at least one rod attached to the backrest and the headrest, and wherein the seat cushion comprises at least one opening for receiving at least one headrest attachment rod, the seat cushion having a front edge adjacent to the opening and extending beyond the front surface of the seat back, and the first capacitive sensor is located at a sixth distance from the front edge; the sixth distance is between 200 mm and 300 mm, and preferably, the sixth distance is equal to 250 mm.

[0018] Advantageously, such positioning of the first capacitive sensor enables it to detect more significant movement or pressure of the seat occupant's shoulder blades.

[0019] -A removable seat cushion intended to be mounted on a backrest comprising an upper surface, and wherein the removable seat cushion comprises a load-bearing portion intended to rest against the upper surface of the backrest, the load-bearing portion comprising a front end intended to be arranged between the upper surface and the front surface of the backrest, and wherein the first capacitive sensor is located at a sixth distance from the front end of the load-bearing portion, the sixth distance being between 200 mm and 220 mm, and preferably, the sixth distance is equal to 210 mm.

[0020] - The seat element comprises a removable seat cushion intended to be placed on a seat comprising a seat cushion and a backrest hinged on the seat cushion, the seat cushion having a cushion surface suitable for receiving an occupant, the removable seat cushion intended to be placed on a cushion surface of the seat cushion of the seat.

[0021] - 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 spaced apart from the fourth capacitive sensor by a fourth distance in the longitudinal direction, the fourth distance being between 30 mm and 50 mm, and preferably, the fourth distance D4' being equal to 40 mm.

[0022] The invention also relates to a seat, in particular a motor vehicle seat, comprising a seat cushion and a backrest hinged on the seat cushion, the backrest having a front surface, a rear surface and an upper surface, the seat comprising a seat element having any of the above-mentioned features, and, when the seat element is attached to the seat, the first capacitive sensor is located at a sixth distance from the edge between the upper surface and the front surface, the sixth distance being between 200 mm and 300 mm, and preferably, the sixth distance is 250 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] [ Figure 1 ] is a perspective view of a seat with a seat element according to the first embodiment placed on the seat;

[0024] [ Figure 2 ] is a schematic cross-sectional view of a seat element according to a first embodiment, wherein the cross section is taken along a mid-plane of the seat element;

[0025] [ Figure 3 ] is a schematic front view of an example of a capacitive sensor arranged in a seat element according to the present invention;

[0026] [ Figure 4 ] is a schematic cross-sectional view of a first variant of the seat element according to the first embodiment; and

[0027] [ Figure 5 ] is a perspective view of a seat with a second variant of the seat element according to the first embodiment located on the seat;

[0028] [ Figure 6 ] is a top view of a seat equipped with a seat element according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0029] In the following description, spatial orientation indications, such as front, rear, top, bottom, up, down, horizontal, vertical, etc., should be interpreted according to the usual use position of the seat in the vehicle and the usual position of the removable cushion arranged on the seat. The front direction is the direction in which the vehicle travels forward. These common positions are as follows: Figure 1 Specifically, the front surface of the backrest is the surface against which the back of the seat occupant rests.

[0030] Figure 1 An example of a seat 2 according to the invention is shown. The seat 2 comprises a seat cushion 4, a backrest 6 hinged on the seat cushion and a headrest 12 attached to the backrest by means of a rod 14.

[0031] The seat cushion 4 has a seat cushion surface 5 which is designed to accommodate the buttocks and part of the legs of a seat occupant.

[0032] The backrest 6 further comprises a front surface 8 , a rear surface 9 , two side surfaces 10 , a lower surface 11 hinged to the seat cushion and an upper surface 13 opposite the lower surface.

[0033] The seat element according to the first embodiment of the invention is a removable backrest cushion 16, that is to say a removable cushion intended to be placed on the front surface 8 of the seat back. The removable cushion 16 comprises at least one padding 18 and a cover 19 arranged around the padding. The padding 18 comprises a layer of foam or padding. The padding may also comprise multiple layers of foam or padding.

[0034] See also Figure 2 , the removable cushion 16 extends in a longitudinal direction X and in 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 in the transverse direction Y. The removable cushion 16 also includes two longitudinal side edges 24, 26 extending in the longitudinal direction X.

[0035] exist Figure 1 and 2 In the illustrated embodiment, the removable cushion 16 also includes two openings 28 or recesses for receiving the headrest rods 14. When the removable cushion 16 is installed on the seat back, the openings have a front edge 30 on the front side 8 of the back and a rear edge 31 on the rear side 9 of the back.

[0036] For ease of description, a longitudinal center plane (X, Z) is defined, which is perpendicular to the mid-plane of the cushion. It intersects the center of the removable cushion along a center line X1. The center line X1 is parallel to the longitudinal side edges 24, 26. The center line X1 is located in the center, that is, midway between the two longitudinal side edges 24, 26. For ease of description, the "first side 32" of the cushion is the side of the cushion located on one side of the longitudinal center plane (X, Z), such as the left side, and the "second side 34" is the side of the cushion located on the other side of the longitudinal center plane, such as the right side.

[0037] Figure 2 An example of a cross-sectional view of a removable cushion 16 according to a first embodiment of the present invention is schematically shown.

[0038] The removable mat 16 includes a first coplanar interdigitated electrode capacitive sensor 36 and a second coplanar interdigitated electrode capacitive sensor 42, hereinafter referred to as first and second capacitive sensors.

[0039] When the pad has a foam layer, the first capacitive sensor 36 and the second capacitive sensor 42 are arranged between the cover 19 and the pad. Alternatively, when the pad has two foam layers, the first capacitive sensor 36 and the second capacitive sensor 42 are arranged between the two foam layers. The first capacitive sensor and the second capacitive sensor extend in the transverse direction Y. They are suitable for measuring capacitance values.

[0040] The first capacitive sensor 36 is located on the first side 32 of the longitudinal center plane (X, Z). The second capacitive sensor 42 is located on the second side 34 of the longitudinal center plane (X, Z).

[0041] The first capacitive sensor 36 is spaced apart from the second capacitive sensor 42 by a first distance D1 between 30 and 50 mm in the longitudinal direction X. Preferably, the first distance D1 is equal to 40 mm. In the illustrated embodiment, the first capacitive sensor 36 is closer to the upper lateral edge 20 of the mat than the second capacitive sensor 42.

[0042] Advantageously, when the first and second capacitive sensors are separated by a first distance D1, the capacitance values ​​they generate enable detection of a torsional position of the body, regardless of the seat size and the morphology of the occupant. The term "twisted position" refers to the rotation of the body around the vertical axis of the spine and the resulting misalignment of the pelvis. Such a torsion may be caused by a driver holding the steering wheel with one hand or a person sitting in an office chair crossing one leg over the other. When the removable cushion is arranged on seat backs of different sizes and for people of different morphologies, the offset between the positioning of the first capacitive sensor and the positioning of the second capacitive sensor enables efficient detection of bad posture.

[0043] Preferably, the first capacitive sensor 36 and the second capacitive sensor 42 are separated by a second distance D2 in the transverse direction Y. The second distance is between 50 and 150 mm. Preferably, the second distance is equal to 80 mm.

[0044] The end of the capacitive sensor toward the center of the seat cushion is used to measure along the longitudinal direction Y. Figure 2 shown.

[0045] Preferably, the seat pad further comprises a third coplanar interdigitated electrode capacitive sensor 38 disposed between the cover 19 and the cushion or between two foam layers of the cushion. The third capacitive sensor 38 is located on the first side 34 of the longitudinal center plane (X, Z).

[0046] Preferably, the first capacitive sensor 36 and the third capacitive sensor 38 are aligned with each other along a first straight line X2 extending in the longitudinal direction X.

[0047] Preferably, the third capacitive sensor 38 is spaced apart from the first capacitive sensor 36 by a third distance D3 in the longitudinal direction X. The third distance D3 is between 250 and 290 mm. Preferably, the third distance D3 is equal to 270 mm. Figure 2 As shown, in the present application, the middle part of the capacitive sensor is used for distance measurement along the longitudinal direction X.

[0048] When the first and third capacitive sensors are spaced this distance apart, the capacitance values ​​produced by these sensors can detect the bending of the seat occupant's back about a horizontal axis, regardless of the seat size and the morphology of the seat occupant. The morphology refers to the general shape of a person. It includes the height and width of a person.

[0049] Advantageously, such positioning of the third capacitive sensor 38 enables detection of more significant movement or pressure of the pelvic portion of the seat occupant.

[0050] Preferably, the removable cushion 16 further comprises a fourth coplanar interdigitated electrode capacitive sensor 40 disposed between the cover 19 and the pad or between two foam layers of the pad. The fourth capacitive sensor 40 is located on the second side 34 of the longitudinal center plane (X, Z).

[0051] Preferably, the fourth capacitive sensor 40 is spaced apart from the third capacitive sensor 38 by a fourth distance D4 in the longitudinal direction X, and the distance is between 30 mm and 50 mm. Preferably, the fourth distance D4 is equal to 40 mm. Figure 2 In the illustrated embodiment, the fourth capacitive sensor 40 is closer to the lower lateral edge 22 of the mat than the third capacitive sensor 38 .

[0052] Preferably, the fourth capacitive sensor 40 is aligned with the second capacitive sensor 42 along a straight line X3 extending in the longitudinal direction X. Preferably, the fourth capacitive sensor 40 is spaced apart from the second capacitive sensor 42 along the longitudinal direction X by a third distance D3.

[0053] Preferably, the fourth capacitive sensor 40 is spaced apart from the third capacitive sensor 38 by a fifth distance D5 in the transverse direction Y. The fifth distance is between 50 mm and 150 mm. Preferably, the fifth distance is equal to 80 mm.

[0054] Also preferably, the fifth distance D5 is equal to the second distance D2.

[0055] In the illustrated embodiment, the first capacitive sensor 36 is closer to the upper lateral edge 20 than the second capacitive sensor 42. The first capacitive sensor 36 is located at a sixth distance D6 from the front edge 30 of the cushion opening 28, the sixth distance D6 being between 200 and 300 millimeters. Preferably, the sixth distance D6 is equal to 250 millimeters. This positioning of the first capacitive sensor 36 enables detection of more significant movement or pressure of the shoulder blades of the seat occupant.

[0056] Preferably, all four capacitive sensors are identical. Figure 3 An example of a first capacitive sensor 36 that can be disposed in the removable cushion 16 is shown.

[0057] 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 a finger attached to the rod. The finger extends perpendicular to the rod. The fingers are spaced apart in a comb-like configuration. The second electrode is positioned relative to the first electrode so that the fingers of the second electrode are between the fingers of the first electrode. An example of the dimensions of the rods and fingers of a capacitive sensor that can be arranged in a detachable mat and the spacing between the rods and fingers is disclosed in the patent application with the publication number FR 3126 776.

[0058] The first electrode 44 is connected to a voltage source via an electrical connection line 48. The voltage source generates a voltage of, for example, 5 V. The second electrode 46 is grounded via the electrical connection line 48.

[0059] The first capacitive sensor 36, the second capacitive sensor 42, the third capacitive sensor 38, the fourth capacitive sensor 40 and the electrical connection lines 48 are arranged on a flexible support 50. The flexible support 50 rests on the foam or padding layer.

[0060] The removable cushion 16 may include a controller 52. The controller 52 may be placed in a pocket 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 electrical connections 48.

[0061] The controller is configured to periodically receive capacitance values ​​from the capacitance sensor.The controller is configured to detect rotation of a body part (particularly a part of the torso) of a seat occupant resting on the seat cushion from the received capacitance values.

[0062] The controller 52 can be a device programmable using software or an application-specific integrated circuit (ASIC). The controller includes a memory and an executable code for implementing a method for detecting rotation of a seat occupant's torso portion from a capacitance value received from a previously disclosed capacitance sensor. The memory includes a random access memory (denoted as RAM) and a read-only memory (denoted as ROM). The memory may include an executable code for implementing a method for detecting rotation of a seat occupant's torso portion, as disclosed in patent application number FR 3120124 published in the name of the applicant on August 26, 2022, and several ranges of capacitance values ​​as disclosed in the present patent application. The range of capacitance value variation can be preset during the learning phase.

[0063] The removable cushion 16 may include a comfort device 54 arranged in the cushion between the cover 19 and the foam layer or between two foam layers of the cushion. The comfort device 54 includes, for example, a vibration device or a pneumatic device that performs a massage function, a ventilation actuator, and a heating device.

[0064] The comfort devices 54 are connected to the controller 52. The controller 52 controls the operation of the comfort devices according to the seat occupant's commands or when incorrect positioning of the seat occupant is detected.

[0065] Figure 2 Eight comfort devices 54 are shown. Alternatively, the removable cushions may include a different number of comfort functions.

[0066] Alternatively, the removable cushion 16 does not include a controller. The electrical connection line 48 is connected to a connector for connecting to a seat cable harness.

[0067] Figure 4 A first variant of the seat element according to the first embodiment is shown. According to this first variant, the seat element comprises only a first capacitive sensor 36 and a second capacitive sensor 42. The first capacitive sensor 36 is spaced a first distance D1 from the second capacitive sensor 42 in the longitudinal direction X. Figure 4 In the embodiment shown by way of example in FIG. 1 , the first capacitive sensor 36 and the second capacitive sensor 42 are located at the upper part of the backrest. Alternatively, the first capacitive sensor and the second capacitive sensor are located at the lower part of the backrest. Then, they are located at the position of the third capacitive sensor 38 and the fourth capacitive sensor 40.

[0068] Alternatively, a removable cushion is designed to cover the front surface 8 of the backrest and the cushion surface 5 of the seat cushion, and the capacitive sensor is arranged only on the cushion portion designed to rest on the seat back.

[0069] Figure 5 A second variant of the seat element according to the first embodiment is shown. According to this first alternative, the seat element is a removable backrest cushion 56, which is identical or similar to the removable cushion 16 according to the first embodiment, except that the removable cushion has no opening 28 or recess. It is placed on the upper surface 13 of the seat. It is attached to the backrest, for example by a tether.

[0070] The removable cushion 56 comprises a bearing portion 60 designed to be supported on the upper surface 13 of the seat. The shape of this bearing portion 60 is similar to the transverse strip of the cushion. The bearing portion 60 comprises a front end 62, which is intended to be arranged between the upper surface 13 and the front surface 8 of the backrest. In this alternative, the first capacitive sensor 36 is located at a sixth distance D6 from the front end 62 of the bearing portion 60, the sixth distance D6 being between 200 and 300 millimeters. Preferably, at the sixth distance D6 from the front end of the bearing portion 60, the sixth distance D6 is 250 millimeters.

[0071] The other technical features of the detachable cushion according to the second alternative are the same as those of the detachable cushion according to the first embodiment, and will not be described in detail. Figure 5 Only a first capacitive sensor is shown, but the removable pad 56 may include two, three or four capacitive sensors.

[0072] Figure 6 A seat element according to a second embodiment is shown. The seat element is a removable seat cushion 66, that is to say a removable cushion intended to be placed on the cushion surface of a seat cushion. The removable cushion comprises at least one padding 18 and a cover 19 arranged around the padding. The padding 18 comprises a layer of foam or filler. The padding may also comprise a plurality of layers of foam or filler.

[0073] The detachable seat cushion 66 is relative to Figure 6 The new coordinate system (X', Y') shown in FIG. 1 is defined. The removable seat cushion 66 extends in a longitudinal direction X' and in a transverse direction Y' perpendicular to the longitudinal direction X'. The removable cushion comprises a front transverse edge 69 and a rear transverse edge 70 extending in the transverse direction Y. The removable cushion 16 also comprises two longitudinal side edges 71, 73 extending in the longitudinal direction X'.

[0074] As with the seat element of the first embodiment, a longitudinal center plane (X', Z') is defined that is perpendicular to the midplane of the seat cushion. The longitudinal center plane (X', Z') is not shown. It intersects the center of the seat cushion 66 along the center line X'1. The center line X'1 is parallel to the longitudinal side edges 71, 73. The center line X'1 is located in the center, i.e., midway between the two longitudinal side edges 71, 73 of the seat cushion. For ease of description, the "first side 72" of the cushion is the side of the cushion that is located on one side of the center line X'1, such as the left side, and the "second side 74" is the side of the cushion that is located on the other side of the center line X'1, such as the right side.

[0075] Preferably, the detachable seat cushion 66 includes a first coplanar interdigitated electrode capacitive sensor 76 and a second coplanar interdigitated electrode capacitive sensor 82, hereinafter referred to as the first capacitive sensor and the second capacitive sensor, respectively.

[0076] The first capacitive sensor and the second capacitive sensor are arranged between the pad 19 and the cover 18. 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 detachable seat cushion. The second capacitive sensor 82 is arranged on the second side 74 of the center straight line X'1 of the cushion.

[0077] The first capacitive sensor 76 is spaced apart from the second capacitive sensor 38 by a first distance D'1 in the longitudinal direction X'. The first distance D'1 is between 30 and 50 mm. Preferably, the first distance D'1 is equal to 40 mm.

[0078] Preferably, the seat cushion 66 includes a third coplanar interdigitated electrode capacitive sensor 78 and a fourth coplanar interdigitated electrode capacitive sensor 80, which are arranged between the cover 19 and the foam layer of the cushion or between the two foam layers of the cushion. The third capacitive sensor 78 is located on the first side 72 of the center line X'1. The fourth capacitive sensor 80 is located on the second side 74 of the center line Z1.

[0079] The third capacitive sensor is spaced apart from the fourth capacitive sensor by a fourth distance D4' in the longitudinal direction X', and the distance is between 30 mm and 50 mm. Preferably, the fourth distance D4' is equal to 40 mm.

[0080] Technical elements of the seat element of the second embodiment that are identical or similar to those of the seat element of the first embodiment have the same reference numerals and will not be disclosed repeatedly.

Claims

1. A seat element (16, 56; 66) for a motor vehicle seat, the seat element comprising a cushion (18) and a cover (19) arranged around the cushion, the seat element extending in a transverse direction (Y; Y') and in a longitudinal direction (X; X'), the seat element comprising two longitudinal side edges (24, 26; 71, 73), a longitudinal center plane ((X, Z); (X', Z')) extending between and in the middle of the two longitudinal side edges, a first side (32; 72) of the seat element being located on one side of the longitudinal center plane and a second side (34; 74) being located on the other side of the longitudinal center plane, characterized in that The seat element comprises a first coplanar interdigitated electrode capacitive sensor (36; 76) arranged on the first side (32; 72) and a second coplanar interdigitated electrode capacitive sensor (42; 82) arranged on the second side (34; 74), the second capacitive sensor (42; 82) being spaced a first distance (D1; D'1) from the first capacitive sensor (36; 76) in a longitudinal direction (X; X'), the first distance being between 30 mm and 50 mm.

2. The seat element (16, 56) according to claim 1, characterized in that The seat element comprises a removable backrest cushion (16) intended to be placed on a seat, the seat (2) comprising a seat cushion (4) and a backrest (6) hinged on the seat cushion, the backrest (6) having a front surface (8) suitable for receiving the back of an occupant, the removable backrest cushion intended to be placed on the front surface (8) of the backrest of the seat (2).

3. The seat element (16, 56) according to claim 2, characterized in that The first capacitive sensor (36) is spaced a second distance (D2) from the second capacitive sensor (42), the second distance being between 50 mm and 150 mm, the second distance (D2) being measured in a transverse direction (Y).

4. The 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 center plane, and wherein, The third capacitive sensor (38) is spaced a third distance (D3) from the first capacitive sensor (36) in the longitudinal direction, and the third distance is between 250 mm and 290 mm.

5. The seat element (16, 56) according to claim 2 further comprises a fourth coplanar interdigitated electrode capacitive sensor (40) arranged on the second side (34) of the longitudinal center plane (X, Z), the fourth capacitive sensor (40) being separated from the third capacitive sensor (38) by a fourth distance (D4) in the longitudinal direction (X), the fourth distance being between 30 mm and 50 mm.

6. Seat element (16, 56) according to claim 5, characterized in that It also includes a third coplanar interdigitated electrode capacitive sensor (38) arranged on the first side (32) of the longitudinal center plane, and wherein the third capacitive sensor (38) is separated from the first capacitive sensor (36) by a third distance (D3) in the longitudinal direction, the third distance (D3) is between 250 mm and 290 mm, and preferably, the third distance is equal to 270 mm, and wherein the fourth capacitive sensor (40) is separated from the third capacitive sensor (38) by a fifth distance (D5), the fifth distance is between 50 mm and 150 mm, and the fifth distance (D5) is measured in the transverse direction (Y).

7. The seat element (16, 56) according to claim 2, characterized in that A removable seat cushion (16) is intended to be mounted on a seat (2) comprising a headrest (12) and at least one rod (14) attached to the backrest and the headrest, and wherein the seat cushion (16) comprises at least one opening (28) for receiving at least one headrest attachment rod (14), the seat cushion (16) having a front edge (30) adjacent to the opening (28) and extending beyond a front surface (8) of the seat back, and wherein the first capacitive sensor (36) is located at a sixth distance (D6) from the front edge (30), the sixth distance being between 200 mm and 300 mm.

8. The seat element (56) according to claim 2, characterized in that A removable seat cushion (56) is intended to be mounted on a backrest (6) including an upper surface (13), and wherein the removable seat cushion (56) includes a load-bearing portion (60) intended to abut against the upper surface (13) of the backrest, the load-bearing portion (60) including a front end (62) intended to be arranged between the upper surface (13) and the front surface (8) of the backrest, and wherein the first capacitive sensor (36) is located at a sixth distance (D6) from the front end (62) of the load-bearing portion, the sixth distance being between 200 mm and 220 mm.

9. The seat element (66) according to claim 1, characterized in that The seat element (66) comprises a removable seat cushion, which is intended to be placed on a seat, the seat (2) comprising a seat cushion (4) and a backrest (6) hinged on the seat cushion, the seat cushion (4) having a seat cushion surface (5) suitable for receiving an occupant, the removable seat cushion being intended to be placed on the seat cushion surface (5) of the seat cushion of the seat (2).

10. Seat element (66) according to claim 9, characterized in that The seat element comprises a third coplanar interdigitated electrode capacitive sensor (78) disposed on the first side (72) and a fourth coplanar interdigitated electrode capacitive sensor (80) disposed on the second side (74), the third capacitive sensor being spaced a fourth distance (D4') from the fourth capacitive sensor in a longitudinal direction (X'), the fourth distance being between 30 mm and 50 mm.

11. The seat element (66) according to claim 1, characterized in that The first distance (D1; D'1) is equal to 40 mm.

12. Seat element (66) according to claim 3, characterized in that The second distance (D2) is equal to 80 mm.

13. Seat element (66) according to claim 4, characterized in that The third distance (D3) is equal to 270 mm.

14. The seat element (66) according to claim 5, characterized in that The fourth distance (D4) is equal to 40 mm.

15. Seat element (66) according to claim 6, characterized in that The fifth distance is equal to 80 mm.

16. Seat element (66) according to claim 7, characterized in that The sixth distance (D6) is equal to 250 mm.

17. Seat element (66) according to claim 8, characterized in that The sixth distance (D6) is equal to 210 mm.

18. Seat element (66) according to claim 8, characterized in that The fourth distance (D4') is equal to 40 mm.

19. A seat (2), in particular a motor vehicle seat, comprising a seat cushion (4) and a backrest (6) hinged to the seat cushion, the backrest (6) having a front surface (8), a rear surface (9) and an upper surface (13); the seat comprising a seat element (16, 56) according to any one of claims 2 to 18, and wherein: When the seat element is attached to the seat, the first capacitive sensor (36) is located at a sixth distance (D6) from the edge between the upper surface (13) and the front surface (8), the sixth distance being between 200 mm and 300 mm, and preferably, the sixth distance is 250 mm.

Images