Patent Description:
Currently, tire pressure sensors may be provided in vehicle tires. Such sensors may be used to automatically monitor tire pressure, and a warning (e.g., a warning light) may be provided to the driver when low pressure is detected. Other aspects of the tire, however, may require manual monitoring and failure to adequately monitor such aspects may cause issues relating to safety. Accordingly, improved monitoring of vehicle tires may be desired.

<CIT> concerns a tire wear detection device that includes a pair of electrodes that are connected to an inner peripheral surface of a tire in a state where the electrodes are separated and insulated from each other.

<CIT> relates to measuring thickness of a material by transmitting an oscillating signal from a first pad, through the material, to a second pad, and measuring the signal reflected back to the first pad.

<CIT> discusses an "active integrated circuit transponder", mounted in or on a vehicle tire.

<CIT>) describes a module arranged at a rim of a wheel or at an inner side of a tire, having a battery, a carrier and an electrically conductive connection provided between the components.

According to the invention there is provided a tire monitoring system according to claim <NUM> and a method providing a tire monitoring system in line with claim <NUM>. According to some embodiments of inventive concepts, a tire monitoring system includes first and second sensor elements, a circuit board, and a housing. The circuitry board includes control circuitry coupled with at least one of the first and second sensor elements, wherein the control circuitry is configured to generate tire tread information based on an electrical response of at least one of the first and second sensor elements. The housing includes a housing material that surrounds the circuit board in a direction parallel with respect to a surface of the circuit board.

According to some other embodiments of inventive concepts, a method provides a tire monitoring system. First and second sensor elements are provided, and a circuit board is provided including control circuitry coupled with at least one of the first and second sensor elements. The control circuitry is configured to generate tire tread information based on an electrical response of at least one of the first and second sensor elements. A housing is formed on the circuit board using a housing material that surrounds the circuit board in a direction parallel with respect to a surface of the circuit board.

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate certain non-limiting embodiments of inventive concepts. In the drawings:.

According to some embodiments of inventive concepts, tire tread monitoring systems (TTMS) may be used to monitor vehicle tire tread wear. A tire tread monitoring system according to such embodiments may use a sensor including two electrodes that may be formed, for example, by printing or other means on a rigid or flexible dielectric substrate. There may be different ways to package such tread wear sensors for tire deployment. One approach for Tire Pressure Monitoring Systems TPMS is a package scheme like the one presented by VDO (http://www. com/passenger-cars/tire-pressure-monitoring-systems-tpms/the-vdo-redi-sensor/). In this approach, the TPMS sensors, battery, sense electronics and RF communications are all housed inside a small carrier roughly <NUM> inch in diameter as shown in <FIG> including a carrier and a lid. The lid is placed over the contents of the carrier and sealed, and this "package" is then placed inside a rubber mount (shown in <FIG>) that is attached to the inside surface of the tire by an adhesive. The base of the package carrier may thus be mounted adjacent to the inside surface of the tire. According to some embodiments of inventive concepts, a tread wear sensor may be mounted in the same carrier and share the power management and RF communications hardware used for TPMS. According to some embodiments of inventive concepts, methods may be provided to integrate tire tread wear and pressure monitoring systems. <CIT> ("Structures and Methods Providing Sensor-Package Integration") discusses integration of a tread sensor into a standard tire pressure monitoring system (TPMS) style package similar to that described by VDO.

Tread wear sensor structures/designs and methods according to some embodiments disclosed herein may enable integration with a tire pressure monitor into a carrier/package.

According to some embodiments, the tread wear sensor may be placed at the base of the carrier (also referred to as the bottom of the carrier) to position the sensor close to the inner tire surface. In some TPMS designs, the battery may be placed at the bottom of the carrier. According to some embodiments, the tread wear sensor (e.g., the tread wear sensor elements) may be positioned between the battery and a base of the carrier. This design may position the tread wear sensor close to the tire surface (e.g., as close as possible) and may reduce/avoid RF (radio frequency) interference from the battery and/or electronics in the package. According to some embodiments, an epoxy or similar underfill or potting material may be used underneath and/or above the tread wear sensor to secure the tread wear sensor. In addition, this underfill/potting material may protect the tread wear sensor from harsh operating conditions including varying humidity and/or mechanical shock/vibration. The orientation of the tread wear sensor could be either upward facing or downward facing.

<FIG> is a cross-sectional/side view of a tread wear sensor (labeled "sensor") mounted inside the carrier of <FIG>. As shown, the tread wear sensor may be provided adjacent a base of the carrier, and an underfill/potting material may be provided on the tread wear sensor. Moreover, sensor leads (e.g., pigtail sensor leads) from the sensor may extend through the underfill/potting material to provide electrical coupling with control circuitry. <FIG> is a top view of the tread wear sensor of <FIG> in the carrier. For purposes of illustration, the tread wear sensor is shown through the underfill/potting material in <FIG>, but it will be understood that the underfill/potting material may cover the tread wear sensor (except for the pigtail sensor leads).

<FIG> is a cross-sectional/side view of the tread wear sensor mounted inside the carrier of <FIG> with a battery and printed circuit board PCB. The pigtail sensor leads ("leads") of the tread wear sensor may extend out of the carrier and may wrap around the battery and printed circuit board PCB. The leads of the tread wear sensor may then be attached to the PCB by soldering (surface mount technology), conductive epoxy, or by a connector or socket. It may be useful to include additional dielectric shielding (not shown in <FIG>) between the battery and the tread wear sensor. According to some embodiments, the underfill/potting material may provide adequate dielectric shielding, but in other embodiments, different/additional layers may be added.

Additional modifications to the tread wear sensor may further facilitate integration with the tire pressure monitor in the final package. According to some embodiments, the tread wear sensor may be encapsulated by applying a thin Kapton, PET (polyethylene terephthalate), or other layer over the top surface of the tread wear sensor after printing. This encapsulation may extend down the length of the leads but leave exposed the ends of the leads for subsequent electrical connection. Metal vias or feedthroughs may be provided in the tread wear sensor substrate (e.g., Kapton), particularly at the ends of the leads to improve subsequent electrical connection. These metal vias/feedthroughs may allow electrical and mechanical interface to the printed traces from either the top or bottom side of the sensor substrate. This may provide a thick, mechanically robust metal layer for connection either by solder, conductive epoxies or socket connectors, allowing for electrical connection from either side of the substrate. In addition, a metal layer may be provided on the backside of the sensor substrate (away from the carrier base and the tire surface) to provide an effective RF ground plane. This ground plane layer may be continuous or discontinuous based on RF characteristics of the sensor.

According to some embodiments, the sensor elements may be provided on a flexible sensor substrate, and mounted so that the sensor elements are between the flexible sensor substrate and the carrier base, and so that the sensor elements are between the flexible sensor substrate and the inner surface of the tire. Moreover, a metal layer may be provided (e.g., as an RF ground plane) on the backside of the sensor substrate so that the sensor substrate is between the metal layer and the sensor elements. In such embodiments, the sensor elements may be between the backside metal layer and the carrier base, and between the backside metal layer and the inner surface of the tire.

A lid (e.g., as shown in <FIG>) may be provided over the carrier of <FIG> to seal the tread wear sensor, battery, and PCB within the carrier/lid package, and the carrier base may be mounted on an inside surface of the tire to be monitored. The structure of <FIG> may thus be used to provide an integrated tread wear sensor and pressure monitor. While one PCB is shown in <FIG> for purposes of illustration, control circuitry may be provided using one or a plurality of PCBs. Moreover, a pressure sensor (e.g., a micro-electro-mechanical-system MEMS pressure sensor) may be provided (inside the carrier/lid package) with the PCB (e.g., mounted on the PCB) to provide tire pressure monitoring. Components of the integrated tire monitoring system are illustrated in the block diagram of <FIG>.

As shown in <FIG>, circuitry may be provided in/on the printed circuit board to provide controller <NUM>, wireless interface <NUM>, and/or pressure sensor <NUM>. Controller <NUM> and/or wireless interface <NUM> may be implemented using one or more integrated circuit devices that may be mounted (soldered) on PCB (or otherwise coupled with PCB). Moreover, pressure sensor <NUM> may be a MEMS pressure sensor that is provided as a discrete device on/in the PCB, and/or pressure sensor <NUM> may be integrated with circuits used to provide controller <NUM> and/or wireless interface <NUM>. As shown in <FIG>, battery <NUM> may be positioned between the PCB and tread wear sensor <NUM> in the carrier, with the tread wear sensor positioned between battery <NUM> and the base of the carrier (which is mounted to the inside surface of the tire).

Controller <NUM> (also referred to as a control circuit or control circuitry) may thus generate tire pressure information based on signals received from pressure sensor <NUM>, and controller <NUM> may thus generate tread wear information based on signals received from tread wear sensor <NUM>. The tire pressure information and/or tread wear information may thus be transmitted through wireless communication interface <NUM> (also referred to as a wireless interface circuit or wireless interface circuitry) to a receiver in the vehicle that provides the information to a controller in the vehicle. The wireless interface <NUM> may thus provide wireless communication (e.g., radio communication) with a receiver in the vehicle to facilitate wireless transmission of tire pressure and/or tread wear information from the spinning tire to the vehicle controller. The wireless interface <NUM> may also receive information (e.g., instructions) from a transmitter in the vehicle, such as instructions to transmit tire pressure and/or tread wear information. While pressure and tire wear sensors are discussed by way of example, other sensors (e.g., a temperature sensor) may also be included in the tire monitoring system. With a temperature sensor, for example, controller <NUM> may generate tire temperature information based on signals received from the temperature sensor, and controller <NUM> may transmit such temperature information through wireless communication interface <NUM> to the receiver in the vehicle.

Operations of the tire monitoring system may be performed by controller <NUM> and/or wireless communication interface <NUM>. For example, controller <NUM> may control wireless communication interface <NUM> to transmit communications (e.g., tread wear and/or tire pressure information) through wireless communication interface <NUM> over a radio interface to a vehicle receiver and/or to receive communications (e.g., requests for information) through wireless communication interface <NUM> from a vehicle transmitter over a radio interface. Moreover, modules may be stored in memory, and these modules may provide instructions so that when instructions of a module are executed by controller <NUM>, controller <NUM> performs respective operations (e.g., operations discussed below with respect to the claims).

<FIG> are schematic diagrams illustrating operation of a tread wear sensor according to some embodiments of inventive concepts. In the illustration of <FIG>, the tread wear sensor is shown on an inside surface of the tire without the other elements of <FIG>/<FIG> to more clearly illustrate operations thereof. Operation of the tread wear sensor is based on the mechanics of how electric fields interact with different materials. As shown in <FIG> and <FIG>, the tread wear sensor (TWS) includes two electrically conductive sensor elements (also referred to as sensor electrodes) side-by-side and very close to each other, and the two sensor elements are positioned adjacent to the inside of the tire as shown in <FIG>. As shown in <FIG>, the carrier base may be between the sensor elements and the inside surface of the tire, but the carrier has been omitted from <FIG> for each of illustration.

The controller <NUM> may thus apply an oscillating electrical voltage to one of the sensor elements while the other sensor element is grounded to generate an electrical field between the two sensor elements (shown as arcs in <FIG>). While most of the electric field may pass directly between edges of the sensor elements, some of the electric field arcs from the face of one electrode to the face of the other electrode through the tire tread (shown by arcs in <FIG>). The tire rubber and tread structure interfere with this "fringing field," and by measuring this interference through the electrical response of the grounded sensor element, the controller <NUM> may thus determine a thickness of the tire above the tread wear sensor.

According to embodiments, a modification of the above disclosed integration scheme is presented where the tread sensor (also referred to as a tread wear sensor), its associated electronics, battery and communications chips are molded inside a rubber mount having outer dimensions similar to those shown in the "boot" of <FIG>, instead of placing the sensor inside a plastic housing including a lid and carrier of <FIG>. Aspects of such embodiments are discussed below:
A custom Printed Circuit PC Board is illustrated in <FIG> according to some examples. The custom PC board may include source electronic signal and sense, computation, RF data transmission and power management circuitry. Such circuitry may be provided using one or more discrete and/or integrated circuit (IC) electronic devices interconnected using conductive traces of the PC board. The PCB of <FIG> may provide circuitry as discussed above with respect to PCB of <FIG> and/or controller <NUM> of <FIG>.

The sensor is illustrated in <FIG> according to some examples. The sensor interfaces with the tire and is electrically connected to the PCB of <FIG>. As shown, the sensor includes two electrodes (Electrode <NUM> and Electrode <NUM>) on a dielectric substrate, and the sensor may be mounted on an inside surface of the tire (opposite a tread block) so that the electrodes are between the dielectric substrate and the inside surface of the tire. The sensor (e.g., tread wear sensor or a tread monitoring sensor) of <FIG> may be provided using structures as discussed above, for example, with respect to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and/or 7B.

The battery of <FIG> may be a coin style battery according to some examples. The power source for the sensor may be a coin cell battery but could be another stored energy device. The battery of <FIG> may be used as discussed above with respect to the battery of <FIG> and <FIG>.

A rubber housing or "boot" according to some embodiments of inventive concepts is illustrated in <FIG>, <FIG>, <FIG> and/or <NUM>. The housing may be a rubber housing specific to the tread sensor components of <FIG>, the rubber housing may be a shared housing for a TPMS system as shown in <FIG>, and/or the rubber housing may be made of compliant materials other than rubber.

According to some embodiments, a tire tread monitoring system (TTMS) may be mounted and/or encased inside a rubber housing (housing) or "boot. " The components encased in the housing may include the sensor, a battery and a PCB that includes circuitry for sensor drive and sense, power management and RF communication. The PCB may also include temperature, humidity, and/or pressure sensors. In embodiments of <FIG> and <FIG>, the sensor electrodes may be encased flush with the surface of the housing such that the sensor electrodes directly contact the tire surface upon mounting. In other embodiments, the electrodes might be fully encased in the housing and not directly in contact with the tire surface. As also shown in <FIG>, the battery may be mounted directly above the sensor and below the PCB. In another embodiment, the battery may by mounted above the PCB or to the side depending on the battery size and shape. <FIG> shows top and bottom views of the housing with the TPMS unit installed. <FIG> shows a cross section of some embodiments that do not include a TPMS unit.

In some illustrated embodiments, the housing may also provide a housing for a tire pressure monitoring sensor (TPMS). In other embodiments, there may be no TPMS and the housing may house only the tire tread sensor elements. In <FIG>, the housing is shown to have a round shape but the shape may vary depending on sizes and shapes of tire tread sensor components.

According to some embodiments, the TTMS may measure tire tread and transmit tread data via Radio Frequency RF signaling outside the tire to an RF receiver. The RF receiver could be a component of a vehicle or a stand-alone mobile receiver. In some other embodiments, the TTMS may transmit data directly to the integrated TPMS system whereby the TPMS system collects the tread data, and retransmits the data to either a vehicle mounted receiver or mobile device, so that the TPMS system acts as a repeater. The TPMS system may simply act as a repeater or may collect the data, compile it with pressure and/or temperature data and transmit it to either a vehicle mounted receiver or mobile device.

<FIG> is a cross sectional view of a sensor housing including a TPMS unit according to some embodiments. <FIG> provides top and bottom views of the sensor housing of <FIG> including a TPMS unit according to some embodiments. <FIG> is a cross sectional view of a sensor housing that includes only the TTMS components (without TPMS components) according to some embodiments. <FIG> is a cross sectional view of a sensor housing mounted inside a tire according to some embodiments.

The housing of <FIG> is formed by molding the housing material on/around the PCBand the sensor (including sensor substrate and sensor electrodes) and optionally the battery. As shown, the housing material may extend between portions of the PCB and battery, between portions of the battery and the sensor, and/or between portions of the PCB and sensor. According to some other embodiments, the PCB, the battery, and/or the sensor may be bonded before forming the housing. For example, a bonding material (different than the housing material) may be used to bond the PCB, the battery, and/or the sensor, and then a molding process (e.g., an injection molding process) may be used to form the housing (also referred to as a boot).

As shown, the housing may include a recess to accept a tire pressure monitoring system TPMS (or portions thereof) that may be provided after forming the housing. A wireless communicative coupling may be provided between the TPMS and the PCB, or an electrical coupling may be provided through the housing between the TPMS and the PCB. With an electrical coupling, for example, a wireless communication interface of TPMS may be used to transmit tread wear information generated by PCB, and/or power may be provided from TPMS to PCB so that a battery is not required in the housing. According to some other embodiments, TPMS, a wireless interface, and/or a power source may be provided separate from the housing, and an electrical coupling with the PCB may be provided through the housing.

The tire monitoring system of <FIG> thus includes first and second sensor elements 1201a and 1201b, a printed circuit board PCB <NUM>, and a housing <NUM>. The circuit board <NUM> includes control circuitry coupled with at least one of the first and second sensor elements 1201a and/or 1201b, where the control circuitry is configured to generate tire tread information based on an electrical response of at least one of the first and second sensor elements.

The housing <NUM> includes a housing material that surrounds the printed circuit board <NUM> in a direction parallel with respect to a surface of the circuit board. The housing material, for example, may be a compliant housing material, such as rubber, and the housing material is molded around the printed circuit board <NUM>.

In addition, a power source <NUM> (e.g., a battery) may be coupled with the printed circuit board, wherein the housing material surrounds the power source (e.g., battery) in the direction parallel with respect to the surface of the printed circuit board <NUM>. The power source may be between the printed circuit board <NUM> and at least one of the first and second sensor elements 1201a and/or 1201b.

According to some embodiments, the housing material of housing <NUM> may define a base adapted to provide an interface with an inside surface of a tire, and respective surfaces of the first and second sensor elements 1201a and 1201b may be exposed through the base of the housing material. According to some other embodiments, the housing material may define a base adapted to provide an interface with an inside surface of a tire, and respective surfaces of the first and second sensor elements 1201a and 1201b adjacent the base may be covered by the housing material.

A wireless communication interface may be provided on the printed circuit board <NUM>, and the wireless communication interface may be coupled with control circuitry on the printed circuit board <NUM>. The wireless communication interface may be configured to wirelessly transmit the tread wear information to a remote receiver. For example, at a least portion of the control circuitry and/or at least a portion of the wireless communication interface may be provided using one or more integrated circuit electronic devices mounted on the printed circuit board <NUM>.

A pressure sensor may also be coupled with the control circuitry, wherein the control circuitry is configured to generate tire pressure information based on an electrical response of the pressure sensor, and wherein the wireless communication interface is configured to wirelessly transmit the tire pressure information to the remote receiver. The pressure sensor, for example, may be provided as a MEMS based pressure sensor on printed circuit board <NUM> and/or in TPMS unit <NUM>.

As shown, sensor elements 1201a and 1201b may be provided on a dielectric sensor substrate <NUM>, and the housing material and a material of the dielectric sensor substrate may be different. Moreover, at least a portion of the dielectric sensor substrate <NUM> may be between the printed circuit board <NUM> and at least one of the first and second sensor elements 1201a and/or 1201b. As discussed with respect to <FIG> and <FIG>, first and second leads may extend through the housing material, wherein the first lead provides electrical coupling between the first sensor element 1201a and the printed circuit board <NUM>, and wherein the second lead provides electrical coupling between the second sensor element 1201b and the printed circuit board <NUM>.

Claim 1:
A tire monitoring system comprising:
first and second sensor elements (1201a, 1201b);
a circuit board (<NUM>) including control circuitry coupled with at least one of the first and second sensor elements, wherein the control circuitry is configured to generate tire tread information based on an electrical response of at least one of the first and second sensor elements;
a housing (<NUM>) comprising a housing material that surrounds the circuit board in a direction parallel with respect to a surface of the circuit board; and characterised in that the housing material being molded on and/or around the first and second sensor elements and the circuit board.