KR20100085969A - Sensor assembly comprising a capacitive proximity sensor - Google Patents

Abstract

A sensor assembly comprises a capacitive proximity sensor (1) mounted to a shaped surface of a body, such as the internal surface of a vehicle bumper, to sense the presence of external objects. The sensor comprises a dielectric film substrate (2) having front and rear major surfaces that, in use, face respectively outwards and inwards of the body, a sensor conductor (6) on the front major surface, and a guard conductor on the rear major surface to provide an electrical shield for the sensor conductor. The surface to which the sensor (1) is mounted is one that does not provide a substantially flat area for direct attachment of the sensor, at least in the sensor conductor region, and, with a view to ensuring the correct functioning of the sensor, the sensor mounting is designed to inhibit the ingress and retention of water/dirt between the sensor and the shaped surface, and to enable a major part of the sensor substrate to be maintained in a substantially flat condition at least in the sensor conductor region.

Description

Sensor assembly with capacitive proximity sensor {SENSOR ASSEMBLY COMPRISING A CAPACITIVE PROXIMITY SENSOR}

Cross Reference to Related Application

This application claims the priority of British Patent Application No. 0719807.0, filed October 10, 2007, the disclosure content of which is incorporated herein by reference in its entirety.

The present invention relates to mounting a capacitive proximity sensor on a body for detecting the presence of an external object. The present invention more specifically (but not exclusively) relates to the mounting of capacitive proximity sensors in vehicles, in particular in vehicle bumpers.

Proximity sensors have been used in a variety of industrial applications to detect the presence of materials and to avoid collisions with articles. In one application, a proximity sensor is installed on the rear and / or bumper of the vehicle, providing a warning signal when the vehicle approaches an object when the vehicle is retracted, so that the driver still conveniently positions the vehicle close to the object. Make sure that the crash is safely avoided.

International Patent Publication WO 01/08925 (AB Automotive Electronics Ltd.) is a vehicle in which two strips of metal or other conductive material are insulated from each other and provided inside the bumper of a vehicle. A capacitive proximity sensor is described. One strip facing outwards from the vehicle is called a sensor plate, and the other strip facing inwards towards the vehicle is called a guard plate. Two plates are connected to the control unit. The control unit monitors the changes that occur in the capacitance between the sensor plate and the (electrical) ground when the vehicle approaches an external object, and displays an indication of the distance between the object and the sensor plate (and thus the vehicle). To provide.

British Patent Publication No. 2 400 666 (also ABS Automotive Electronics ltd.) Is directed to screen-printing the sensor plate and the guard plate with conductive ink on opposite sides of the plastic film substrate or to the plastic film substrate. Reference is made to the manufacture of capacitive proximity sensors of the type described in WO 01/08925 by forming sensor plates and guard plates from laminated aluminum foil. British Patent Publication No. 2 400 666 further describes the use of a retaining system to hold a sensor in a vehicle bumper without the need for adhesives.

The present invention relates to a capacitive proximity sensor of the type in which the sensor conductor and the guard conductor are arranged on opposite sides of the dielectric film substrate. Sensors of that type offer the advantage that they can be manufactured in a cost effective manner in the form of flat sheets which are relatively easy to store and handle. The sensor may be a flat support surface and a surface that is somewhat non-planar because the sensor is flexible (most typically, this surface will be a surface with only one axis of curvature but also with limited curvature about the second axis). Can be applied relatively easily as well). However, in order to ensure as much as possible avoiding the formation of folds and creases in the sensor substrate, which can interfere with the sensor's correct function and durability, such sensors are curved in more complex shapes (eg, inside of some vehicle bumpers). Care is required when applied to a support surface having a (ie concavely curved) inner surface. Folds and creases in the sensor substrate can cause dirt and / or water to invade and be retained between the sensor and the support surface. In particular, the accumulation of water between the sensor conductor and the support surface can affect the capacitive function of the sensor, while the accumulation of dust somewhere between the sensor and the support surface can cause the surface of the sensor to wear out and cause the sensor to malfunction. Can be. There is an additional risk that when water is retained between the sensor and the support surface the sensor will be damaged as a result of water freezing.

One method of reducing the number of folds and creases formed in the sensor substrate when applied to the shaped support surface is tapered cutouts at appropriate points on the substrate to make it easier to conform the substrate to the shape of the support surface. to make a tapered cut. This increases the complexity of the attachment process because the shape and location of the cutout must be carefully selected in view of the shape of the support surface to achieve the desired result and to avoid introducing too many weak points in the sensor substrate.

The present invention is directed to providing a system for attaching a capacitive proximity sensor to a support surface that makes it possible to avoid such problems and is robust enough to withstand the forces and environmental conditions that may be encountered in use. In certain cases where the sensor must be attached to the rear of the vehicle or to the vehicle bumper, the attachment system can monitor temperature changes and exposure to dust and / or water and / or oil as well as forces caused by normal use of the vehicle. It must be able to withstand the environmental conditions it may contain.

The present invention relates to a sensor assembly comprising a capacitive proximity sensor mounted to a surface of a body for sensing the presence of an external object. The sensor comprises front and rear major surfaces facing the outside and inside of the body, respectively, in use, sensor conductors on the front major surface, and guard conductors on the rear major surface providing electrical shields for the sensor conductors. And a dielectric film substrate having the same. The invention also relates to a situation in which the surface of the body on which the sensor is mounted does not provide a substantially flat area for direct attachment of the sensor at least in the sensor conductor zone. According to the invention, the sensor is mounted on a surface, which inhibits ingress and retention of water / dust between the sensor and the surface (at least during normal use) and keeps the sensor substantially flat at least in the sensor conductor zone. Is provided.

In connection with the present disclosure and when applied to the surface of the body, the term “substantially flat” means that the surface is non-planar but still causes the sensor to adhere to the surface without folding and / or crimping at least in the sensor conductor region. To the extent only non-planar. Thus, when applied to a surface, “substantially flat” may include a surface having a single axis of curvature and may even include some surface that also has a limited curvature about a second axis. When applied to a sensor, the term “substantially flat” includes the case where the sensor is non-planar but only non-planar to the extent that it does not fold and / or fold in the sensor conductor region.

In general, the sensor is mounted to a support surface that does not allow direct attachment at least in the sensor conductor zone without the formation of creases and / or folds in the sensor. Nevertheless, the sensor remains substantially flat at least in the sensor conductor zone and is inhibited (at least during normal use) of water / dust ingress between the sensor and the support surface. In some cases, in normal use, it may be possible to allow the passage of water (eg, rainwater) between the sensor and the support surface without affecting the sensor's performance. This may be the case, for example, with a superguard conductor in the sensor as described in British Patent Publication No. 2,374,422.

In an embodiment, the surface of the body may be an inner surface and / or may be curved inwardly (ie concavely curved). The surface may for example be a curved inner surface of the bumper of the vehicle, in which case the use of the present invention increases the range of vehicle bumpers in which the capacitive proximity sensor may be conveniently employed. In some embodiments, the sensor can be easily employed in a vehicle bumper that is curved about two axes (eg, vertical axis and horizontal axis). In other words, the sensor can be employed in bumpers that have a compound curvature, as well as bumpers that are substantially flat or curved about a single axis only. Advantageously, when the sensor further comprises a superguard conductor on the front major surface of the substrate, the sensor mount allows the superguard conductor to be positioned relatively close to the curved inner surface of the bumper. The sensor assembly may be provided to the vehicle bumper after manufacture, but may also be included during the bumper manufacturing process.

The present invention provides a capacitive proximity sensor mounted on a surface of a body for sensing the presence of an external object, the sensor comprising: front and rear major surfaces directed toward and outside the body, respectively, in use, and sensor conductors on the front major surface; A dielectric film substrate having a guard conductor on the rear major surface that provides an electrical shield for the sensor conductor, wherein the bend line allows the sensor to bend to shape the sensor for attachment to the surface of the body; It further provides this pre-formed capacitive proximity sensor. The sensor according to this aspect of the invention can be mounted to the vehicle bumper using, for example, mechanical attachment means such that the sensor closely follows the shape of the bumper.

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a vehicle bumper assembly, the method comprising providing a dielectric film substrate having a sensor conductor on the front major surface and a guard conductor on the rear major surface providing an electrical shield for the sensor conductor. step; Providing a vehicle bumper, wherein the inwardly curved inner surface of the vehicle bumper is shaped so as not to provide a substantially flat area for at least the direct attachment of the sensor in the sensor conductor zone; Positioning the sensor inside the bumper with the front and rear major surfaces of the sensor facing towards and away from the bumper, respectively; And mounting the sensor to the inner curved surface of the bumper in such a manner that ingress and retention of water / dust between the sensor and the bumper is suppressed but the sensor remains at least substantially flat in the sensor conductor region. Provide additional methods.

According to yet another aspect of the present invention, there is provided a method of manufacturing a vehicle bumper assembly, comprising: providing a vehicle bumper; Providing a capacitive proximity sensor comprising a dielectric film substrate having a sensor conductor on the front major surface and a guard conductor on the rear major surface providing an electrical shield for the sensor conductor; Providing a former shaped to fit the curved inner surface of the bumper; Positioning the sensor on the former with the rear major surface of the sensor facing the former; And inserting the former into the bumper to position the sensor on the inner surface of the bumper. The former may be an infill for the bumper that remains in place inside the bumper after the sensor is positioned on the inner surface of the bumper.

Accordingly, the present invention provides a capacitive proximity sensor mounted on a shaped surface of a body for sensing the presence of an external object, the sensor comprising front and rear major surfaces respectively facing outward and inward of the body and a front major surface in use. A dielectric film substrate having a sensor conductor on and a guard conductor on the rear major surface providing an electrical shield for the sensor conductor, wherein the sensor is positioned on the former shaped to fit the shaped surface of the body; The former also provides a capacitive proximity sensor that can be used to position the sensor on the shaped surface.

For illustrative purposes only, a sensor assembly according to the present invention will be described with reference to the accompanying drawings.

1 is a schematic plan view of a main surface of a capacitive proximity sensor;
2 is a schematic enlarged cross-sectional view of the sensor, taken at line 2-2 of FIG.
3 is a schematic plan view of a sensor mounted on an inner surface of a vehicle bumper;
4 is a schematic cross-sectional view taken at line 4-4 of FIG.
5 shows a sensor similar to that of FIG. 3 but mounted in an alternative manner on the inner surface of the vehicle bumper.
6 is a schematic cross sectional view taken at line 6-6 of FIG.
7 is a schematic plan view of a capacitive proximity sensor of the type shown in FIGS. 1 and 2 with a differently shaped substrate.
8 is a schematic cross-sectional view of the sensor of FIG. 7 mounted on the inner surface of the bumper, taken at lines 8-8.
9 is a schematic longitudinal cross-sectional view of the assembly of FIG. 8.
10 shows a sensor similar to that of FIG. 3, but mounted in an alternative manner on the inner surface of the vehicle bumper.
FIG. 11 is a schematic cross sectional view taken at line 11-11 of FIG. 10;
FIG. 12 is a view similar to that of FIG. 11, but showing the sensor mounted in an alternative manner on the inner surface of the vehicle bumper. FIG.
13 and 14 are views similar to those of FIGS. 3 and 4, respectively, but showing sensors mounted in an alternative manner on the inner surface of the vehicle bumper.
15 is a schematic plan view of another capacitive proximity sensor of the type shown in FIGS. 1 and 2;
FIG. 16 is a schematic exploded cross-sectional view of the sensor of FIG. 15 mounted on the inner surface of the bumper, taken at lines 16-16.
FIG. 17 is a schematic diagram of a method of mounting a sensor of the type shown in FIG. 1 to a vehicle bumper; FIG.
18-20 are schematic cross-sectional views illustrating components of another sensor assembly in accordance with the present invention.

The term "film substrate" as used herein refers to an article having extensions in two directions, at least five times, more preferably at least five extensions in which the extension is essentially perpendicular to the two directions. Refers to an article exceeding ten times. More generally, the term "film" is used herein to refer to a flexible sheet-like material, as well as film, as well as sheeting, foil, strip, laminate, ribbon ( ribbon) and the like.

As used herein, the term "dielectric" refers to a material having a specific bulk resistivity of at least 1 x 10 ¹² Ωcm, more preferably at least 1 x 10 ¹³ Ωcm, measured according to ASTM D 257. As used herein, the term “electrically-conductive” refers to a material having a surface resistivity of less than 1 Ω / cm 2 measured according to ASTM B193-01.

The capacitive proximity sensor 1 of FIGS. 1 and 2 comprises a dielectric film substrate layer 2 whose periphery shape is determined by the intended position of the sensor as described further below. In FIG. 1, the substrate layer 2 is schematically shown as being generally rectangular in shape.

The front major surface of the substrate layer 2 shown in FIG. 1 supports the sensor conductor 6 and the superguard conductor 7 electrically insulated from each other by the interposed substrate material on the surface of the substrate layer. The superguard conductor 7 essentially comprises a flat electrically-conductive strip extending along the length of the substrate layer 2. The sensor conductor 6 exhibits a more complex design and consists essentially of several selectively planarized conductive strips 6a extending parallel to each other along the length of the substrate layer 2 and adjacent to both ends of the strip 6a. Thus, several additional parallel (but shorter) selectively planarized electrically-conductive strips 6b form a lobe type region. The strips 6a, 6b of the sensor conductors are connected together in two lobe zones by an electrically-conductive strip 6c extending at an angle across the entire array of strips 6a, 6b. It will be appreciated that the specific shape and number of strips 6a, 6b, 6c shown in FIG. 1 are not absolute and can be varied. In FIG. 2 both the sensor conductor 6 and the superguard conductor 7 are shown as attached to the substrate layer 2 by adhesives 6 ′ and 7 ′, respectively.

The rear major surface of the substrate layer 2, which is not visible in FIG. 1, supports the guard conductor 8 in the form of an electrically-conductive layer, which is preferably the area occupied by the sensor conductor 6 on the other side. At least covers an area of the substrate corresponding in size. In the sensor shown in FIGS. 1 and 2, the guard conductor 8 essentially completely covers the rear surface of the substrate layer 2 to which the guard conductor is attached (in this case by the adhesive 8a). The guard conductor 8 is electrically insulated from the sensor and the superguard conductors 6, 7 by the interposed dielectric substrate layer 2.

As described so far, the substrate layer 2 with the sensor conductor 6, the guard conductor 8 and the superguard conductor 7 is attached to any suitable surface of the body, for example inside the bumper of the vehicle. And function as a capacitive proximity sensor. For that purpose, in the case of a vehicle bumper, the substrate layer has the front major surface (i.e. the surface supporting the sensors and superguard conductors 6, 7) of FIG. 1 facing outward from the vehicle and the rear major surface (i.e. the guard). The surface supporting the conductors 8) is located in an inward facing direction towards the vehicle. Conductors 6, 7, 8 are connected to an electronic control unit (not shown) that can monitor changes in capacitance between the sensor conductor 6 and the (electrical) ground as the vehicle approaches external objects. This provides the driver with an indication of the distance between the object and the sensor conductor (and thus the vehicle). During the monitoring process, the guard conductor 8 acts as a shield which reduces the sensitivity of the sensor conductor 6 to anything behind the sensor conductor in the direction of the vehicle body while the electrical signal is superguarded. The guard conductor 8 applied to the conductor 7 makes it even more prominent to minimize the effect on the signal from the sensor conductor 6 of water droplets passing on the outside of the bumper in rainy conditions. Further information regarding the operation of this type of capacitive proximity sensor can be found, for example, from the aforementioned WO 01/08925 and British Patent Publication No. 2 400 666, and British Patent Publication No. 2 374 422 (also Available from ATV Automotive Electronics, Inc.). The measurement and processing of signals from capacitive proximity sensors is described, for example, in WO 02/19524 (also ATV Automotive Electronics).

The entire sensor 1 can be encased in a protective cover film (not shown) if necessary.

In some cases, especially when the surface of the body on which the sensor 1 is to be mounted is substantially flat or if it is not flat, it has a relatively simple shape (eg curved in only one direction and / or relatively few irregularities). It may be possible to apply the sensor directly to the surface, for example using an adhesive applied over the entire front surface of the sensor. In most cases, however, the surface on which the sensor will be mounted will have a more complex shape (eg, the surface may be curved in two orthogonal directions and / or have irregularities such as protruding ribs). Significant care will be required to prevent the formation of creases and creases in the sensor substrate layer 2 when the sensor is applied directly to the surface. In many cases, for example, in the use of sensors on concavely curved surfaces inside the vehicle bumper, folds and / or corrugations are formed in the substrate layer 2 or shaped appropriately for the substrate layer. It may not be possible to apply the sensor directly to the surface without making any cuts. As has already been described, in particular the area of the sensor conductor 6, because for example water and / or dust can penetrate and be retained between the sensor 6 and the support surface, which can interfere with the correct function and durability of the sensor. Folds and / or folds of the substrate layer 2 in are undesirable. Cutting the substrate layer 2 so that the substrate layer fits the support surface may result in more satisfactory results, but is complex, time consuming and expensive.

3 and 4 show that the sensor 1 has a shaped surface of the body without the formation of folds and / or folds in the substrate layer 2 and without having to cut the substrate layer 2 so that it can be fitted to the surface. One way it can be attached is shown. In the example shown in FIGS. 3 and 4, the sensor 1 is attached to the inner surface 10 of the vehicle bumper 11, but it will be appreciated that the sensor may be attached in a similar manner to other shaped surfaces.

In the assembly of FIGS. 3 and 4, the sensor 1 is attached to the inner surface 10 of the vehicle bumper 11 only at the periphery 12 of the substrate layer 2, and instead of following the inward curvature of the bumper surface, It extends substantially flat across the bend such that there is a gap 13 between the sensor and the bumper surface. The attachment of the periphery 12 of the sensor 1 to the bumper surface 10 may be any, taking into account the nature of the substrate layer 2 and the surface to which the substrate layer is attached (including, for example, by adhesive or welding). It may be carried out in a suitable manner. In certain cases where the substrate layer 2 is a polymer film, suitable adhesives for attaching the periphery 12 of the sensor 1 to the bumper surface 10 include hot melt adhesives, for example, St. Paul, Minn. Adhesives available under the trade name "Jet-melt ™ 3748 Adhesive" from 3M Company; And moisture / chemically cured adhesives, such as the "Scotch-Weld ™ Structural Plastic Adhesives" and "Scotch-Weld ™ Polyurethane Reactive Ads" from 3M Company. Adhesives available as "Scotch-Weld ™ Polyurethane Reactive Adhesives" are included, while suitable welding includes ultrasonic welding, welding and laser welding. The attachment of the upper portion of the sensor periphery 12 to the bumper surface 10 should in particular form a seal that prevents water and / or dust from penetrating between the sensor and the bumper. Attachment of the rest of the sensor periphery 12 to the bumper surface may form a similar seal, but in some cases it may be sufficient or desirable to attach the rest of the sensor periphery to the bumper surface only at spaced locations.

5 and 6 show an assembly similar to that shown in FIGS. 3 and 4 except that the sensor 1 is mounted on a non-metallic carrier substrate 15 having a larger surface area, wherein The back surface is located adjacent to the carrier substrate. In this arrangement, it is the carrier substrate rather than the sensor substrate layer 2 that is attached to the inner surface 10 of the vehicle bumper 11 at the perimeter 16. Such an arrangement may be desirable if the size, shape or material of the sensor substrate layer 2 does not allow easy attachment of the sensor 1 directly to the bumper. The carrier substrate 15 can be, for example, a flexible film, rigid injection-molded component, machined component or extruded polymer sheet.

According to a change applicable to the assemblies of FIGS. 3 and 4 and 5 and 6, the sensor 1 (or the larger substrate 15 on which the sensor is mounted) is formed at its periphery (the inner surface of the bumper 11). 10) It is not attached directly. Instead, the sensor is attached to the bumper by an attachment strip having a flexible zone extending along its length, in which the strip can be bent to ensure accurate positioning of the sensor. An embodiment of that change is shown in FIGS. 18-20.

In the embodiment shown in FIG. 18, the sensor 1 is connected to the inner surface of the vehicle bumper 11 by an attachment strip 60 comprising two parts 61, 62 mechanically interlocked along the length of the strip. 10) is attached. Mechanical interlocking includes a re-closable fastener 63 that allows the sensor 1 to be attached to and removed from the bumper 11 as needed. In addition, hinges 64 are formed in the attachment strip 60, one along each side of the fastener 63, providing increased flexibility. The reclosable fastener 63 may be of any suitable type, an example being a "press-to-close zipper" which is well known for use in plastic storage bags.

One portion 61 of the attachment strip 60 is foamed around the periphery of the sensor 1 (or, in the case of the assemblies shown in FIGS. 5 and 6, the periphery of the larger substrate 15 on which the sensor is mounted). It is fixed by the tape 65. The other part 62 of the attachment strip 60 is selected to ensure that the sensor 1 extends substantially flat across the curve of the bumper as described above with reference to FIGS. 3 to 6. Is secured by foam tape 66 at an appropriate location on the inner surface 10 of the < RTI ID = 0.0 > The hinge 64 of the attachment strip 60 provides additional flexibility to make it possible to accommodate the bends of the bumper, including the bends of the end sections of the bumper even in the case of a lot of attachment strips. Depending on the shape of the sensor 1 and / or bumper 11, it may not be necessary for the attachment strip 60 to extend around the entire periphery of the sensor, in some cases for example the upper part of the periphery of the sensor. Thus it may be sufficient to provide the attachment strip 60 only.

Attachment strip 60 may be formed from any suitable polymeric material, for example by extrusion. If the hinge 64 itself imparts sufficient flexibility to the attachment strip 60 to enable the attachment strip to receive the bends of the bumper 11, it is necessary to remove the sensor 1 from the bumper if necessary. Closable fastener 63 may be omitted. Foam tapes 65 and 66 used to secure the attachment strip 60 to the sensor and to the bumper may be replaced with any suitable alternative, including, for example, other types of adhesive tapes, adhesive layers, and welding. As described above with reference to FIGS. 3 and 4, the attachment of the upper portion of the sensor periphery to the bumper surface 10 should in particular form a seal that prevents water and / or dust from penetrating between the sensor and the bumper. .

FIG. 19 illustrates a modification of the attachment system of FIG. 18. In this case, a portion 62 of the attachment strip 60 is formed with a guide channel 70 directly opposite the foam tape 66, with an applicator roller (not shown) formed on the foam tape 66. Can be positioned to apply to the inner surface 10 of the bumper 11. In addition, the side 71 of the guide channel adjacent the reclosable fastener 63 protrudes above the fastener to allow moisture to penetrate into the space between the sensor 1 and the bumper 11 between the two parts of the fastener. Lips 72 are formed that reduce the risk. The use of the guide channel 70 is not limited to the attachment strip 60 including the reclosable fastener, and similar guide channels can be used for the attachment strip without the reclosable fastener, FIGS. 5 and FIG. It will be appreciated that it may also be used for the substrate 15 of the assembly shown in FIG. 6. In these cases, the lip 72 would not be needed.

In the embodiment shown in FIG. 20, the reclosable fasteners 63 of FIGS. 18 and 19 are omitted, and the attachment strip 60, which is now a one-piece component, is shown in the attachment strip 60. A hinge section 75 is formed that folds in half along its length, thereby reducing the area of the inner surface 10 of the bumper 11 occupied by the attachment strip.

7 to 9 show other ways in which the capacitive proximity sensor 1 of the type shown in FIGS. 1 and 2 can be attached to the inner surface 10 of the vehicle bumper 11 or to another shaped surface. Illustrated. Even in this case, the sensor 1 is mounted (e.g., laminated) on the carrier substrate 20 with the rear surface of the sensor positioned adjacent to the carrier substrate. The carrier substrate 20 is characterized in that the carrier substrate is specially shaped and the bend line 21 is pre-formed in the carrier substrate so that the carrier substrate can conform to the shape of the bumper in both the vertical and horizontal directions, 5 and 6 are different from the carrier substrate. The bend line 21 is arranged to lie outside the area of the carrier substrate occupied by the sensor conductor 6 (and preferably outside the area occupied by the sensor 1 or at the edge of that area). The carrier substrate (and possibly the entirety of the sensor or at least a major part of the sensor) remains substantially flat, allowing the carrier substrate to conform closely to the shape of the bumper. The carrier substrate 20 may be attached to the bumper surface 10 by adhesive or by welding as described above with reference to FIGS. 3-6. Alternatively, since the carrier substrate 20 in this case can very closely follow the shape of the bumper, it may be possible to use a clip 22 or some other form of mechanical attachment means to secure the carrier substrate to the bumper. Can be. The mechanical attachment means 22 is formed as an integral part of the bumper 11 and arranged to be located in the pre-formed attachment hole 23 of the carrier substrate 20, thereby facilitating attachment of the sensor 1 to the bumper. Can be.

The arrangement shown in FIGS. 7 to 9 creates a small gap between the inner surface 10 of the bumper 11 and the sensor 1, which arrangement allows the bumper configuration to allow water and / or dust to enter the gap. It is appropriate when reducing the risks to be retained. The configuration of the bumper may in some cases allow the passage of water (typically rain) through the gap, but this may be particularly acceptable where the sensor 1 comprises a superguard conductor as described above.

10 and 11 illustrate the use of a pre-formed support 25 for the sensor 1, which supports on one side 26 to fit the inner surface 10 of the bumper 11 and on the other side. It is shaped to provide a substantially flat surface 27 on which the sensor 1 is mounted. The support 25 may be formed from any suitable material, preferably a closed cell polymer foam material, from which the desired shape may be provided. Suitable materials are polyethylene, polyurethane and polystyrene foams. The support may be formed in a mold having the same shape as the bumper 11 or by machining. The support 25 can then be attached to the inner surface 10 of the bumper 11 by an adhesive, and the sensor 1 can likewise be adhesively bonded to the support. Alternatively, the sensor 1 may first be attached to the bumper (eg, as described above with reference to FIGS. 3 and 4) and then the support material may be injected into the gap between the sensor and the bumper.

Depending on the internal shape of the bumper 11, in some cases the pre-formed support 25 of FIGS. 10 and 11 may be omitted and a sufficiently thick layer of compressible material, for example polymer foam, may be applied to the front face of the sensor 1. It may be possible to laminate so that the sensor fits smoothly inside the bumper. This type of arrangement may be appropriate when the inner surface of the bumper is substantially flat, except for the presence of some irregularities such as ribs that are standing upright.

FIG. 12 shows a further modification of the arrangement shown in FIGS. 3 and 4, wherein the sensor 1 is a bumper surface 10 at the periphery of the sensor by means of adhesive foam strips 30, which may be continuous or several pieces. ) Is attached. As shown, the foam strip 30 extends around the perimeter of the sensor but this is not absolute. If necessary, an additional foam strip 31 can be located in the gap 13 between the sensor 1 and the bumper 11 to provide further support to the sensor. If desired, a similar foam strip 31 may be provided in the gap 13 between the sensor 1 and the bumper 11 in the arrangement shown in FIGS. 3 to 6. Foam strips 30 and 31 may be commercially available adhesive foam tapes, for example.

Further use of a foam strip to attach the sensor 1 to the bumper 11 is shown in FIGS. 13 and 14. In this case, a wider adhesive foam tape 35 is employed across the upper part of the sensor 1 in the area where the sensor conductor 6 is located, attaching the sensor to the inner surface 10 of the bumper. The foam tape 35 suppresses the ingress and retention of water / dust between the sensor and the bumper surface 10 in the region of the sensor conductor and also keeps that region of the sensor substantially flat. On the other hand, the lower part of the sensor extends downwardly toward the lower part of the bumper, substantially freely hanging along the contour of the bumper surface 10. If necessary, the lower part of the sensor 1 may be attached to the bumper surface 10 but only in spaced positions 36. Attachment at these spaced locations 36 may be made by adhesive foam tape patches or in any other suitable manner.

15 and 16 show a modification of the arrangement shown in FIGS. 13 and 14, wherein a reinforcing strip 40 is further provided along the top of the sensor 1 on the rear major surface of the sensor. The reinforcing strip 40 advantageously acts to bend the sensor into the bumper and to assist the attachment of the sensor to the bumper surface 10 through the foam tape 35. As shown in FIG. 15, the reinforcing strip extends beyond the sensor at each end to provide locations where the sensor can be independently attached to the bumper 11. FIG. 16 shows an exploded cross-sectional view of the sensor of FIG. 15 with vehicle bumper 11, in addition to reinforcing strip 40, foam tape 35, strip 40, sensor 1 and foam tape 35. Shows adhesive layers 42, 43, 44 that are attached to each other and to the bumper. 16 also shows an adhesive tape patch 46 that attaches the lower portion of the sensor 1 to the bumper 11 and the adhesive 44 on the foam tape 35 until the sensor 1 is in place in the bumper. ), A release liner 45 is shown.

FIG. 17 shows a method of mounting a sensor 1 of the type shown in FIGS. 1 and 2 on the inner surface 10 of the vehicle bumper 11. The method requires the use of a former 50, wherein the front face 51 of the former is shaped to correspond to the shape of the inner surface 10 of the bumper. The former 50 may be shaped in a mold having the same shape as the bumper 11 or by machining. The sensor 1 is located on the front face 51 of the former 50 with the rear major surface of the sensor (ie guard conductor 8) adjacent to the front face 51, where the sensor is of any suitable type. In a manner such as, for example, by a relatively low-strength adhesive. Because the front face 51 is convex, it is easier to adhesively position the sensor to this front face than to the inner curved side of the bumper 11, and if necessary the procedure is a placement point on the front face 51. Can be assisted by providing them. When it is necessary to attach the sensor 1 to the inner surface 10 of the bumper 11, the front major surface of the sensor or the inner surface of the bumper is coated with an adhesive and the former 50 is subsequently inserted into the bumper to require the sensor. Put it in a position where it Since the shape of the front face 51 of the former corresponds to the shape of the inner surface 10 of the bumper, accurate placement of the sensor 1 can be achieved relatively easily. The former 50 is then withdrawn and separated from the sensor 1 relatively easily since the sensor is now attached to the bumper 11 by a stronger adhesive.

The former 50 is preferably reusable and the former is formed from a low cost material that can be easily molded into the internal shape of the bumper. Advantageously, the front face of the former has at least some degree of elasticity to assist in attaching the sensor 1 without forming noticeable folds and / or folds. Suitable materials for the former are acrylonitrile-butadiene-styrene (ABS) copolymers. It is further advantageous if the sensor 1 can be stored on the former 50 in the required shape before use.

Alternatively, the former 50 may be a foam infill intended to remain inside the bumper, in which case the bond between the former and the sensor will have a permanent nature.

In the method shown in FIG. 17, the adhesive can be applied to the front face of the sensor 1 well before the sensor is positioned in the bumper 11, in which case the adhesive is applied to the inner surface of the bumper ( It can be protected by a release liner that is removed only when it is about to be attached to 10).

In each of the above-described arrangements, the superguard conductor 7 on top of the sensor 1 is still located relatively close to the inner surface of the bumper, which eventually affects the sensor of water droplets passing on the outside of the bumper in rainy conditions. It can still perform the intended function of minimizing.

Although the above description relates in particular to the attachment of the sensor 1 to the inner surface of the vehicle, there are many other situations where a capacitive proximity sensor may be used and may need to be attached to the shaped surface. For example, in the case of vehicles, proximity sensors may be placed on any non-conductive panel, such as door panels and bonnet lids, for the purpose of detecting impending collisions and operating appropriate safety devices (eg airbags). Can be used for Capacitive proximity sensors can be used on moving objects, such as robot arms, to control movement and prevent collisions, or to detect detectors (e.g., to approach a person or object) to respond to moving objects. Sensor for controlling the automatic door). Capacitive proximity sensors can also be used to detect whether space is occupied, for example to determine whether an individual seat is occupied in a vehicle and, if necessary, to activate a warning signal indicating that the seat belt is not being used. Can be. A further use of the capacitive proximity sensor is as a touch sensor that is activated when a person or object comes in contact directly or through a thin insulator layer. Many other uses will be apparent to those skilled in the art, and the specific uses described above are provided by way of example only.

Claims (34)

A sensor assembly comprising a capacitive proximity sensor mounted on a surface of a body to detect the presence of an external object, the sensor assembly comprising:
(i) The sensor is a guard on the rear major surface which provides, in use, front and rear major surfaces respectively facing the outside and inside of the body, the sensor conductors on the front major surface, and an electrical shield for the sensor conductors. ) A dielectric film substrate having a conductor;
(ii) the surface of the body is shaped to provide at least a substantially flat area for direct attachment of the sensor in the sensor conductor zone;
(iii) a sensor assembly such that ingress and retention of water / dust between the sensor and the surface is suppressed and the sensor is kept at least substantially flat in the sensor conductor region. The sensor assembly of claim 1, wherein the surface of the body is an inner surface of the body. The sensor assembly of claim 1, wherein the surface of the body is curved inwardly. The sensor assembly of claim 1, wherein the body is a vehicle bumper and the surface of the body is an inner surface that is curved inwardly of the bumper. 5. The sensor assembly of claim 4, wherein the sensor substrate is attached directly to the inner surface of the bumper at the periphery of the sensor substrate in such a way that the sensor substrate extends substantially flat across the inward curvature of the inner surface. The inner surface of the bumper at the periphery of the carrier substrate according to claim 4, wherein the sensor substrate is mounted on the carrier substrate, the carrier substrate extending in a substantially flat state across the inward curvature of the inner surface. Directly attached sensor assembly. 7. The sensor assembly of claim 5 or 6, wherein the attachment of the upper portion of the periphery of the sensor / carrier substrate to the inner surface of the bumper forms a seal that inhibits the ingress of water / dust between the sensor and the bumper. . 8. The sensor assembly of claim 7, wherein the remaining portion of the periphery of the sensor / carrier substrate is attached to the inner surface of the bumper at spaced locations. The sensor assembly of claim 5, wherein the sensor / carrier substrate is welded or adhesively bonded to the inner surface of the bumper. The sensor assembly of claim 4, comprising a sensor support attached to the interior of the bumper, the support being shaped to fit on the inner surface of the bumper on one side and to have a flat surface on which the sensor is mounted on the other side. The sensor assembly of claim 10, wherein the support comprises a foam material. The sensor assembly of claim 4, wherein the sensor is attached to the inner surface of the bumper by foam material. 13. The sensor assembly of claim 12, wherein the front major surface of the sensor is laminated to a layer of foam material attached to the inner surface of the bumper. The sensor assembly of claim 12, wherein the sensor is attached to the inner surface of the bumper by at least one foam strip at the perimeter of the sensor substrate. 15. The sensor assembly of claim 14, wherein the foam strip in the upper portion of the sensor substrate forms a seal that inhibits ingress of water / dust between the sensor and the bumper. The sensor assembly of claim 15, wherein the lower portion of the sensor is attached to the inner surface of the bumper at spaced locations. The sensor assembly of claim 12, wherein the foam is adhesively attached to the sensor and to the inner surface of the bumper. The sensor assembly of claim 4, wherein the sensor substrate is bent to follow an inwardly curved portion of the inner surface while maintaining the sensor conductor region substantially flat. 19. The sensor assembly of claim 18, wherein the sensor is attached to the inner surface of the bumper by mechanical attachment means. 20. The sensor assembly of claim 19, wherein the mechanical attachment means is located in a pre-formed opening of the sensor substrate. The sensor assembly of claim 4, wherein the sensor mount includes a reclosable mechanical fastener, whereby the sensor can be removed from and repositioned from the vehicle bumper. 5. The longitudinally-extending hinge of claim 4, wherein the sensor mount includes an attachment strip extending along the periphery of the sensor and connecting the sensor to the inner surface of the bumper, the attachment strip being the center to allow the attachment strip to bend. Sensor assembly with zones. The sensor assembly of claim 22, wherein the attachment strip is welded or adhesively bonded to the inner surface of the bumper and / or to the sensor. A capacitive proximity sensor mounted on the surface of the body to detect the presence of foreign objects,
The sensor comprises a dielectric film substrate having front and rear major surfaces respectively facing outward and inward of the body, a sensor conductor on the front major surface, and a guard conductor on the rear major surface providing an electrical shield for the sensor conductor; ,
And the sensor substrate is pre-formed with a bend line that allows the sensor to bend to shape the sensor for attachment to the surface of the body. 25. The sensor of claim 24, wherein the bend line is located outside of the region of the substrate where the sensor conductor is located. 26. The sensor of claim 24 or 25, wherein the sensor substrate is provided with a pre-formed opening that allows the sensor to be attached to the surface of the body. A method of manufacturing a vehicle bumper assembly,
(i) providing a capacitive proximity sensor comprising a dielectric film substrate having a sensor conductor on the front major surface and a guard conductor on the rear major surface providing an electrical shield for the sensor conductor;
(ii) providing a vehicle bumper, wherein the inwardly curved inner surface of the vehicle bumper is shaped to provide at least a substantially flat area for direct attachment of the sensor in the sensor conductor zone;
(iii) positioning the sensor inside the bumper with the front and rear major surfaces of the sensor facing towards and away from the bumper, respectively; And
(iv) mounting the sensor to the inner curved surface of the bumper in such a way that ingress and retention of water / dust between the sensor and the bumper is suppressed but the sensor remains substantially flat at least in the sensor conductor region;
How to include. A method of manufacturing a vehicle bumper assembly,
(i) providing a vehicle bumper;
(ii) providing a capacitive proximity sensor comprising a dielectric film substrate having a sensor conductor on the front major surface and a guard conductor on the rear major surface providing an electrical shield for the sensor conductor;
(iii) providing a former shaped to fit the curved inner surface of the bumper;
(iv) positioning the sensor on the former with the rear major surface of the sensor facing the former; And
(v) inserting the former into the bumper to position the sensor on the inner surface of the bumper
How to include. 29. The method of claim 28 including withdrawing the former from the bumper after the sensor is positioned on the inner surface of the bumper. 30. The method of claim 28 or 29, wherein the sensor is attached to the inner surface of the bumper by an adhesive. 31. The method of any of claims 28-30, wherein the adhesive is applied to the front major surface of the sensor, the adhesive is protected with a release liner, and the release liner is removed before the sensor is positioned on the inner surface of the bumper. Removing the method. A capacitive proximity sensor mounted on a shaped surface of the body to detect the presence of foreign objects,
The sensor comprises a dielectric film substrate having front and rear major surfaces respectively facing outward and inward of the body, a sensor conductor on the front major surface, and a guard conductor on the rear major surface providing an electrical shield for the sensor conductor; ,
A sensor is positioned on the shaped former to fit the shaped surface of the body, whereby the former can be used to position the sensor on the shaped surface. 33. The sensor of claim 32, wherein the sensor is mounted to the curved inner surface of the vehicle bumper and the former is an infill for the bumper. 5. The sensor assembly of claim 4, wherein the sensor further comprises a superguard conductor on the front major surface of the substrate, wherein the sensor mount is such that the superguard conductor is positioned relatively close to the inner surface curved inside of the bumper.

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