Patent Description:
Aspects of the disclosure generally relate to a pressure sensing mat configured to aid in the prevention of pressure injuries, otherwise known as decubitus ulcers.

Pressure injuries, otherwise known as decubitus ulcers, pressure ulcers or bedsores, are lesions developed when a localized area of soft tissue of a subject is compressed between a bony prominence and an external surface for a prolonged time. Pressure injuries could appear in various areas of the body, such as elbows, knees, pelvis, lower back, and ankles. Development of pressure injuries are based on a combination of factors, such as, unrelieved pressure, friction, shearing forces, humidity, and temperature.

Patients lying in hospital beds and other surfaces often suffer from pressure injuries. Pressure injuries are a risk for patients in different hospital departments. For instance, pressure injuries may be in issue for patients lying on an operating table during an operation. Patients lying in hospital beds in other departments (e.g. intensive care unit, neo natal care unit, step down units, etc.) are also prone to pressure injuries. However, pressure injuries are not limited to hospitalized patients. Individuals confined to wheelchairs are prone to suffer from pressure injuries, especially in their pelvis, lower back, and ankles. Nursing and rehabilitation hope residents also can suffer from pressure injuries. Therefore, there is a relatively large number of settings within the hospital and in other environments where individuals may encounter problems with pressure injuries.

Although easily preventable or treatable if found early, if a pressure injury lingers, it becomes painful and treatment is both difficult and expensive. In many cases, pressure injuries can prove fatal, even under the auspices of medical care. According to one estimate, <NUM> million people suffer from pressure injuries in the United States each year, resulting in over <NUM>,<NUM> deaths annually. Pressure sensing mats have been utilized in hospital bed settings to aid in the prevention of pressure injuries. The pressure sensing mats use capacitive or resistive sensors to track the pressure exerted on different regions of the body of a patient lying in the hospital bed.

<CIT> discloses a flexible pressure-sensing pad and a method of manufacturing the same. The pad includes first electrode <NUM>' on first plastic film <NUM>' and second electrode <NUM>' on second plastic film <NUM>'. The first and second electrodes <NUM>' and <NUM>' are each comprised of sets of parallel electrodes that are oriented at right angles. Each of the parallel electrodes of each set have the same width.

<CIT> discloses a pressure-detection mat including conductive layers 3220a and 3220b supported by separate substrates 3210a and 3210b, respectively. This construction is shown in Fig. 2d.

According to one aspect of this disclosure, a pressure sensing mat is provided, which is subject of independent claim <NUM>. The pressure sensing mat includes a first portion and a second portion. The first portion includes a first conductive layer and a first non-conductive layer that is layered to the first conductive layer. The second portion includes a second conductive layer and a second non-conductive layer that is layered to the second conductive layer. The first conductive layer is continuous except for a plurality of discontinuities defining a plurality of conductive strips oriented in a first direction. The second conductive layer is continuous except for a plurality of discontinuities defining a plurality of conductive strips oriented in a second direction. The first portion includes a first end and a second end. Each conductive strip of the first plurality of conductive strips are formed as columns including a first column and a second column. The first column has a first width and is spaced apart from the first end by a first distance. The second column has a second width greater than the first width and is spaced apart from the first end by a second distance, greater than the first distance. The pressure sensing mat also includes an insulative layer disposed between the first and second portions. The pluralities of first and second conductive strips form a conductive strip matrix having a plurality of capacitors. Each of the capacitors of the plurality of capacitors is configured to provide a capacitance indicative of a pressure applied at each capacitor of the plurality of capacitors.

A pressure sensing mat system of the pressure sensing mat may include a nontransitory computer-readable medium having computer readable instructions stored thereon that is configured to be executed by a processor to receive capacitance data from the plurality of capacitors and determine capacitance based on the capacitance at each of the plurality of capacitors indicative of a pressure applied to the pressure sensing mat at each of its plurality of capacitors.

When the pressure sensing mat is used to detect a pressure of an individual, the first portion of the pressure sensor mat may be arranged to face towards the individual. The second end of the mat may be configured to be arranged beneath a head of the individual.

A number of columns may be disposed between the first column and the second column. A width of the first column and a width of the second column may differ. The width of each of the columns disposed between the first and second columns may increase monotonically from the first end to the second end.

The plurality of conductive strips of the first conductive layer may include a plurality of rows and the at least one conductive strip of the second conductive layer may include a plurality of columns. The plurality of rows and the plurality of columns may be arranged orthogonally to each other, and in other embodiments, in a non-parallel orientation with respect to each other.

The insulative layer may be comprised of a foam material.

The first non-conductive layer may be continuous except for a third plurality of discontinuities. The third plurality of discontinuities may correspond to the first plurality of discontinuities.

The first conductive layer may be disposed between the first non-conductive layer and the insulative layer.

The second non-conductive layer may be continuous except for a fourth plurality of discontinuities. The fourth plurality of discontinuities may correspond to the third plurality of discontinuities.

The second conductive layer may be disposed between the second non-conductive layer and the insulative layer.

According to another aspect of this disclosure, a pressure sensing mat is provided. The pressure sensing mat may include a first portion and a second portion. The first portion may include a first conductive layer that may be sandwiched between a first non-conductive layer and a non-conductive layer. The first non-conductive layer and the first conductive layer may define a first set of channels that may at least partially enclose a first conductive strip that may extend in a first direction. The second portion may include a second conductive layer that may be sandwiched between a third non-conductive layer and a fourth non-conductive layer. The third non-conductive layer and the second conductive layer may define a second set of channels that may at least partially enclose a second conductive strip that may extend in a second direction. The pressure sensing mat may include an insulative layer that may be disposed between the first portion and the second portion. The first conductive strip and the second conductive strip may form a capacitor that may be configured to provide a capacitance indicative of a pressure applied to the capacitor.

The first set of channels may at least partially enclose a third conductive strip and the second set of channels may at least partially enclose a fourth conductive strip. The third conductive strip and the fourth conductive strip may form a second capacitor that may be configured to provide a capacitance indicative of a pressure applied to the second capacitor. The first portion may include a first set of conductive leads.

The first portion may include a second set of conductive leads. The first conductive strip may be disposed in a left region of the first portion and the third conductive strip may be disposed in a right region of the first portion.

The first set of conductive leads may be disposed on a first side of the first portion and at least a portion of the second set of conductive leads may be disposed on a second side of the first portion, that may oppose the first side.

The first set of conductive leads may be formed by a third set of channels that may extend substantially in the second direction and may be defined by the first non-conductive layer and the first conductive layer.

The first set of conductive leads may be formed by a fourth set of channels that may extend in the first direction and may be defined by the first non-conductive layer and the first conductive layer.

The first set of conductive leads may be disposed in a connection region of the pressure sensor mat that may include a peripheral area and a medial area. The first set of conductive leads may include a first conductive lead and a second conductive lead. The first conductive lead may have a first length and may be disposed in the peripheral area. The second conductive lead may have a second length, that may be greater than the first length and may be disposed in the medial area.

The first set of conductive leads may include a number of conductive leads disposed between the first conductive lead and the second conductive lead. A length of the each of the conductive leads disposed between the first conductive lead and the second conductive lead may monotonically decrease from the peripheral area to the medial area.

The second set of conductive leads may include a first segment, a second segment, and a third segment. The first segment may be disposed on the second side of the first portion. The second segment may extend in the first direction from the first set of conductive leads. The third segment may extend from the second segment.

The first segment may be substantially orthogonal to the second segment.

At least one of the conductive leads of the first set of conductive leads has a first width and the first conductive strip has a second width that is greater than the first width.

The first conductive layer may have a first surface area and the first non-conductive layer may have a second surface area and the second non-conductive layer may have a third surface area. The first surface area may be greater than the second and third surface areas.

The first portion may have a first thickness and the first set of channels may have a first depth that may be less than the first thickness.

The first and second non-conductive layers may be laminated to the conductive layer.

The first conductive layer may be formed of copper.

The first conductive layer may have a surface resistivity of at least <NUM> ohms.

According to another aspect of this disclosure, a method of making the pressure sensing mat is provided, which is subject of the further independent claim. The method includes providing a first laminated sheet including the first non-conductive layer, a third non-conductive layer, and the first conductive layer sandwiched therebetween; providing a second laminated sheet including the second non-conductive layer, a fourth non-conductive layer, and the second conductive layer sandwiched therebetween; forming the first portion by removing portions of the first laminated sheet to define the first plurality of discontinuities to form the first plurality of conductive strips extending in the first direction by applying a laser to melt portions of the first laminated sheet; forming the second portion by removing portions of the second laminated sheet to define the second plurality of discontinuities to form the second plurality of conductive strips extending in the second direction; attaching the first portion to a first side of the insulative layer; and attaching the second portion to a second side of the insulative layer.

The removing steps may each include etching the first and second laminated layers. As one example, the etching may be accomplished by applying a laser to melt the portions of the first and second laminated layers.

As used in the specification and the appended claims, the singular form "a," "an," and "the" comprise plural referents unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.

The term "substantially" or "about" may be used herein to describe disclosed or claimed embodiments. The term "substantially" or "about" may modify a value or relative characteristic disclosed or claimed in the present disclosure. In such instances, "substantially" or "about" may signify that the value or relative characteristic it modifies is within ± <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or <NUM>% of the value or relative characteristic.

Aspects of the disclosure generally relate to a capacitive pressure sensing mat configured to aid in the prevention of pressure injuries. Other capacitive pressure sensing mats have been proposed. In one previous implementation, the pressure mat is composed of a matrix of knitted conductive fabric spaced apart by an insulator and connected by a woven ribbon to form a plurality of electrical capacitors. The knitted conductive fabric matrix is produced by standard processes associated with textile manufacturing. The material and manufacturing processes for these knitted conductive fabric pressure sensing mats may be costly thus requiring them to be reused several times to make their use economically feasible. Reusing the pressure mat may require the mat to be cleaned and sanitized after each use and may create sanitation issues of the mat is not sufficiently cleaned or sanitized between patients. Also, these knitted conductive fabric pressure sensing mats need to be specially designed and manufactured for different operating environments, e.g. intensive care units, operating rooms, nursing homes, wheelchairs. Therefore, in some instances, these pressure sensing mats do not provide a modular solution.

Pressure mats composed of knitted fabric may require individual calibration for accuracy and precision. Knitted fabrics include conductive threads or yarns that are relatively elastic and deformable. Available pressure mats are calibrated before use. During the calibration process, the capacitance of each sensor in the matrix is measured for one or more known pressures. The functional relationship between the known pressures and measured capacitance at each sensor is used to calibrate each sensor. Geometrical tolerances of knitted fabrics may have a relatively large range e.g., <NUM> to <NUM>, thereby adding variability to the capacitance measurements.

The capacitive pressure sensing mat of the present disclosure may be formed of spaced apart laminated conductive sheets. The geometrical tolerances of the laminated conductive sheets may have relatively smaller range e.g., <NUM> microns to <NUM> microns, than the knitted fabric matrix. Because the laminated conductive sheets have a narrower tolerance band as compared to pressure mats composed of knitted fabrics, calibration may be streamlined relative to sensing mats composed of knitted fabrics. In some instances, the use of laminated conductive sheets may obviate the need to calibrate every pressure mat before each pressure mat is used. As one example, a statistical analysis for a predetermined number of pressure mats may be used to determine the required frequency of calibrating the pressure mats composed of laminated conductive sheets. Decreasing the frequency and quantity of calibration processes may create efficiencies in manufacturing and may reduce costs.

One or more of the capacitive pressure sensing mats of the present disclosure may include relatively inelastic material such laminated conductive sheets that may mitigate relative movement between two or more layers and two or more sensors of the sheet as compared to known pressure mats composed of knitted fabrics. The knitted fabrics over time may begin to elongate and such elongation may reduce the useful life of the pressure mat. The relatively inelastic material of the pressure mat of the present disclosure may last longer by avoiding this potential issue.

Available pressure sensing mats are typically plugged into a power source and connected to a computer or controller to collect the measured data. One or more of the capacitive pressure sensing mats of the present disclosure may be configured for wireless power and communication. The capacitive pressure sensing mats of the present disclosure may be capable of communicating with a wireless network and powered by a rechargeable battery. The capacitive pressure sensing mats of the present disclosure may be configured to be disposable for use in the operating room. The pressure sensing mats of the present disclosure may be adaptable to a modular manufacturing method where the laminated sheet material may be cut to different sizes from the same stock material so that the laminated conductive sheets can be applied to many different use cases and settings. The pressure sensing mats disclosed in embodiments of the present disclosure provides one or more technical solutions to one or more of the technical drawbacks of the currently proposed pressure sensing mat.

Referring generally to the figures, a pressure sensing mat <NUM> is provided. The pressure sensing mat <NUM> may include a first portion <NUM> and a second portion <NUM>. An insulative layer <NUM> may be disposed between the first portion <NUM> and the second portion <NUM>. As shown in <FIG>, the first portion <NUM> may include a first conductive layer <NUM> that may be sandwiched between a first non-conductive layer <NUM> and a second non-conductive layer <NUM>. The first non-conductive layer <NUM> and the first conductive layer <NUM> may define a first set of channels <NUM>. The first set of channels <NUM> may at least partially enclose a first conductive strip <NUM>. As shown in <FIG>, the second portion <NUM> may include a second conductive layer <NUM> that may be sandwiched between a third non-conductive layer <NUM> and a fourth non-conductive layer <NUM>. The second conductive layer <NUM> and the third non-conductive layer <NUM> may define a second set of channels <NUM> that may at least partially enclose a second conductive strip <NUM> that may extend in a second direction. With the exception of the channels <NUM>, <NUM>, the first conductive layer <NUM> and the second conductive layer <NUM>, respectively, may be continuous. The first conductive strip <NUM> and the second conductive strip <NUM> may form a matrix of capacitors (e.g. a capacitor <NUM> that may be configured to measure capacitance indicative of a pressure applied to the capacitor <NUM>).

The first set of channels <NUM> may at least partially enclose a third conductive strip <NUM> and the second set of channels <NUM> may at least partially enclose a fourth conductive strip <NUM>. The third conductive strip <NUM> and the fourth conductive strip <NUM> may form another capacitor <NUM>. As one example, the first conductive strip <NUM> may be disposed within a left-side region of the first portion <NUM> and the third conductive strip <NUM> may be disposed in a right-side region of the first portion, when viewing the first conductive layer <NUM> in <FIG>.

The first portion <NUM> may include a first set of conductive leads <NUM> and a second set of conductive leads <NUM>. The first set of conductive leads <NUM> includes first conductive portions <NUM> and the second set of conductive leads <NUM> includes first conductive portions <NUM>. The driver <NUM> (as shown in <FIG>) is configured to supply voltage to the capacitors <NUM> through the first and second set of conductive leads <NUM> and <NUM>. The processor <NUM> (as shown in <FIG>) may be configured to measure the potential across the capacitors <NUM>, calculate impedance values for each capacitor <NUM>, and store the data in a data storage unit <NUM>.

The pressure sensor mat may include a first side <NUM>, a second side <NUM>, opposing the first side <NUM>, a first end <NUM>, and a second end <NUM>. The first end <NUM> and the second end <NUM> may extend between the first and second sides <NUM>, <NUM>. The first set of conductive leads <NUM> may be disposed on the first side <NUM> of the first portion <NUM>. At least a portion of the second set of conductive leads <NUM> may be disposed on the second side <NUM> of the first portion <NUM>. The first set of conductive leads <NUM> may be formed by a third set of channels <NUM> defined by the first conductive layer <NUM> and at least one of the first non-conductive layer <NUM> or the second non-conductive layer <NUM> that may extend in a direction parallel to the first side <NUM>, or second side <NUM>, or both. The first set of conductive leads <NUM> may be formed by a fourth set of channels <NUM> that may extend in a direction that is parallel the first end <NUM>, second end <NUM>, or both.

As shown in <FIG>, the pressure sensing mat <NUM> may include a connection region <NUM> that may be configured to engage or be connected with a connector (not illustrated). The connection region <NUM> may include a peripheral region 154a and a medial region 154b. The first set of conductive leads <NUM> may include a first conductive lead <NUM>, disposed in the peripheral region 154a, and a second conductive lead <NUM> that may be disposed in the medial region 154b. The first conductive lead <NUM> may be shorter than the second conductive lead <NUM>. A number of conductive leads may be disposed between the first conductive lead <NUM> and the second conductive lead <NUM>. A length of each of these additional conductive leads may monotonically decrease from the peripheral region 154a to the medial region 154b.

As shown in <FIG>, the second set of conductive leads <NUM> may include a first segment 134a, that may be disposed on the first side <NUM> of the first portion <NUM>, a second segment 134b, and a second segment 134c. The second segment 134b may extend in the first direction from the first segment 134a to the third segment 134c. The third segment 138c may extend between the second set of conductive leads <NUM> and the second segment 134b. As one example, the first segment 134a may be positioned substantially orthogonal to the second segment 134b. The conductive leads <NUM>, <NUM>, or the first conductive portions <NUM>, <NUM>, or both, may each have a width that is greater than a width of one or more of the conductive strips <NUM>, <NUM>, <NUM>, <NUM>.

In one or more embodiments, the conductive strips <NUM>, <NUM> of the first conductive layer <NUM> may be formed by columns and the conductive strips <NUM>, <NUM> of the second conductive layer <NUM> may be formed by rows. A width or a distance of each of the columns or conductive strips disposed between the conductive strips <NUM>, <NUM> may differ. As one example, the width of each of the columns or conductive strips disposed between the conductive strips <NUM>, <NUM> may monotonically increase between the first end <NUM> and the second end <NUM>. When the pressure sensing mat <NUM> is used to detect pressure applied by an individual, the first portion <NUM> may be arranged to face towards the occupant. As one example, the second end <NUM> may be arranged beneath the head area or beneath the head and neck area of the individual. Because an individual's head and neck area may move e.g., tilt up, slide side-to-side, or roll, relatively more than the rest of an occupant's body, the larger conductive strips disposed near the second end <NUM> may provide better resolution than the smaller conductive strips disposed near the first end <NUM>.

Reference is now made to the block diagram of <FIG>, showing an embodiment of a pressure sensing may system <NUM>. The system <NUM> may include at least one pressure sensing mat <NUM> including a plurality of sensors such as capacitors <NUM>, a driver <NUM>, a control unit <NUM> which may be connected to a power source <NUM>, a processor <NUM>, a data storage unit <NUM> and a display unit <NUM>. Power may be supplied via a power cord connected to a wall outlet, or via battery power, optionally rechargeable. Battery support also allows for movement of the bed without requiring a powering off of the system <NUM>. As a safety measure and for compliance tracking, caregiver authentication may be required via a shutdown guard <NUM> to confirm powering off of the control unit <NUM>, such as with entry of a caregiver's employee identification number. While the system identified in <FIG> is a capacitive sensor system, in other embodiments, other methods can be utilized, such as resistive or piezoresistive systems.

The capacitors <NUM> may be arranged at different locations on the pressure sensing mat <NUM>. In an example, the capacitors <NUM> may be arranged in a two-dimensional grid across the surface of the pressure sensor mat <NUM>. The driver <NUM> may be configured to supply voltage to the capacitors <NUM> in the pressure sensing mat <NUM>, and the processor <NUM> may measure the potential across the capacitors <NUM>, calculate impedance values for each capacitor <NUM>, and store the data in a data storage unit <NUM>. The stored data may be further processed, analyzed, and displayed on the display unit <NUM>, such as a computer screen, laptop, personal digital assistant (PDA), tablet device, mobile phone screen, printed sheet, or integrated display screen. Although presented in the block diagram of <FIG> as separate blocks, the system <NUM> may optionally be integrated into a stand-alone system.

Referring now to <FIG>, an individual care environment <NUM> may include a number of sub-systems 400a through <NUM> in communication with a common remote-control center <NUM>. The individual care environment <NUM> may be in a hospital, nursing home, home care or rehabilitative care environment, as examples. If the individual care environment <NUM> is a hospital, the common remote-control center <NUM> may be a nursing station. As shown in <FIG>, each of the sub-systems 400a-<NUM> includes a bed. The sub-systems 400a through <NUM> may be configured to communicate with the common remote-control center <NUM>, for example at a nursing station. This communication can be provided via wiring to a nurse call system, or alternatively via wireless communication (e.g., BLUETOOTH, ZIGBEE, Wi-Fi, cellular, etc.) to the nursing station. Alternatively, the sub-systems 400a-<NUM> may be located remotely from one another, for example each in an individual home, and the remote-control center <NUM> may be a manned observation station.

<FIG> illustrates a perspective view of a portion of the pressure sensing mat <NUM>. The first portion <NUM> is positioned above the second portion <NUM> and the insulative layer <NUM>. As one example, the first portion <NUM>, the second portion <NUM>, and the insulative layer <NUM> may be elongated and rectangular. The first portion <NUM> may include the first set of channels <NUM> that may at least partially enclose the first conductive strip <NUM>. The second portion <NUM> may include the second set of channels <NUM> that may at least partially enclose a second conductive strip <NUM>. The first conductive strip <NUM> may extend in the first direction, such as side-to-side, and the second conductive strip <NUM> may extend in the second direction, such as end-to-end. The dashed lines extending between the first portion <NUM> and the second portion <NUM> may represent a capacitor <NUM>. While one capacitor <NUM> is shown, a number of capacitors are formed at each point of intersection between the conductive strips in the first portion <NUM> and the conductive strips in the second portion <NUM>.

As one example, the insulative layer <NUM> may be formed by a non-conductive material. In other words, the material of the insulative layer <NUM> may not allow a flow of charge such as electrical current through or across the insulative layer <NUM>. The non-conductive material may be film comprised of a thermoplastic polyurethane (TPU), polyethylene terephthalate (PET), foam or other suitable material.

The first portion <NUM> and the second portion <NUM> may each be mechanically attached to the insulative layer <NUM> by an adhesive. As one example, a double-sided tape (DST) may be laid along either the insulative layer <NUM> or the first portion <NUM>, the second portion <NUM>, or both. The insulative layer <NUM> may then be laid on to the first and second portion <NUM>, <NUM> and vice-versa.

<FIG> illustrates the pressure sensing mat <NUM> according to one or more embodiments. As one example, the pressure sensing mat <NUM> may include one or more covers <NUM> that may be fixed directly to either the first portion <NUM> or the second portion <NUM>, or both. The cover <NUM> may be fixed to the first and second portions <NUM>, <NUM> by an adhesive such as double-sided tape (DST), liquid adhesive e.g. glue that may be applied as a spray or a number of beads. The adhesive may be applied to outer portions of the cover <NUM> or the first and second portions <NUM>, <NUM> or to inner portions of the same.

The covers <NUM> may be formed of a fabric or a polymeric material. As one example, the material of the covers <NUM> may be formed of a water-resistant material that is configured to prevent a liquid from penetrating through the cover <NUM> to the first and second portions <NUM>, <NUM>. If water or other liquid penetrates the cover <NUM>, the liquid may cause a short of one or more of the capacitors <NUM>. As one example, the cover <NUM> may be composed of polytetrafluoroethylene (PTFE) or expanded PTFE. A water-resistant cover <NUM> may be useful when the pressure sensing mat <NUM> is used by burn patients or within an operating room environment where liquids from the patient's body or otherwise may be deposited on the cover <NUM>.

As another example, one or more of the covers <NUM> may extend the longevity of the pressure sensing mat <NUM>.

<FIG> illustrates a top view of the first conductive layer <NUM>. The first conductive layer <NUM> may define the first set of channels <NUM> that may enclose the first conductive strip <NUM> and the third conductive strip <NUM>. The first set of channels <NUM> are depicted by the black lines disposed on either side and the ends of the conductive strips <NUM>, <NUM>. The first conductive strip <NUM> may have a width W1 and the third conductive strip <NUM> may have a width W3 that may be greater than the first width. At least one of the conductive strips disposed between the first conductive strip <NUM> and the third conductive strip <NUM> may have a width W2. The second width W2 may be less than the third width W3 and greater than the first width W1. The first conductive strip <NUM> may be spaced apart from the first end <NUM> by a first distance L1, one of the conductive strips disposed between the first and third conductive strips <NUM>, <NUM> may be spaced apart by a second distance L2, and the second conductive strip <NUM> may be spaced apart from the first end <NUM> by a third distance L3. The third distance L3 and the second distance L2 may each be greater than the first distance L1.

The first conductive layer <NUM> may include a right region A1 and a left-region A2, as represented by dashed lines on the left side and right side of <FIG>. As mentioned above, the left-region A2 may include wider conductive strips than conductive strips within the right-region A1. As such, the left-region A2 may be positioned beneath the occupant's head or neck region.

<FIG> illustrates a detailed view of the connecting region <NUM> of the first portion <NUM>. The connecting region <NUM> includes a first conductive portions <NUM>, <NUM>. The first conductive portions <NUM>, <NUM> may include the peripheral portions 154a and a medial portion 154b disposed therebetween. The first conductive lead <NUM> may be disposed near the peripheral portion 154a and the second conductive lead <NUM> may be disposed near the medial portion 154b. The conductive leads <NUM>, <NUM> and a number of other conductive leads of the first conductive portions <NUM> are depicted as the white lines arranged vertically and disposed between channels of the fourth set of channels <NUM>, depicted as black lines adjacent to the vertical white lines. The first conductive portions <NUM> may be formed by a sixth set of channels <NUM> depicted as vertical black lines disposed in within the dashed lines enclosing the first conductive portions <NUM>.

The fifth set of channels <NUM> and the second set of conductive leads <NUM> may extend between the first conductive portions <NUM> and a number of the conductive strips. As an example, the outermost channels of the fifth set of channels <NUM> may extend to the conductive strip that is positioned furthermost from the connection region <NUM>. And the innermost channels of the fifth set of channels <NUM> may extend to the conductive strip positioned at a medial portion of the first portion <NUM>, such as the conductive strip on the line W2.

The third segment 134c of first set of conductive leads <NUM> may extend between the first conductive portions <NUM> and the second segment 134b of the first set of conductive leads <NUM>. The channels, represented by the black lines, and the conductive leads <NUM> of the third segment 134c may be positioned orthogonally with respect the channels of the second segment 134b of the conductive leads <NUM>. As an example, the channels and the conductive leads <NUM> of the first segment 134c positioned near a periphery of the pressure sensing mat <NUM> may have the same length as the channels of conductive leads <NUM> of the first segment 134c positioned closer to the conductive strips.

The outer most channels and conductive leads of the third segment 134c of first set of conductive leads <NUM> may extend to a conductive strip disposed towards a medial portion of the first portion <NUM>, such as the conductive strip to the right of the line W2. And the innermost channels and conductive leads of the third segment 134c of first set of conductive leads <NUM> may extend to a conductive strip positioned closest to the first end <NUM>, such as the first conductive strip <NUM>.

<FIG> illustrates a detailed view of portions of the first set of conductive leads <NUM>. The first segment 134a of the first conductive leads may extend along and may be disposed between the first side <NUM> and the conductive strips. The second segment 134b may extend between the third segment 134c and the first segment 134a.

<FIG> illustrates a top plan view of the second portion <NUM>. The second portion may include a right region A3 and a left region A4. The right region A3 may be disposed below or above the right region A1 of the first portion <NUM> and the left region A4 may be disposed below or above the left region A1.

The second portion <NUM> may include the second set of channels <NUM> that may enclose the conductive strips of the second portion <NUM>. Each of the conductive strips may extend between a channel disposed closest to the second end <NUM> and a third set of conductive leads <NUM>. The conductive strip positioned closest to the second side <NUM>, such as the second conductive strip <NUM>, may have a length L4 and the conductive strip positioned closest to the first side <NUM> may have a length L5, which may be greater than the length L4.

<FIG> illustrates a detailed view taken along the lines 5A in <FIG>. The second portion <NUM> may include a connector region <NUM> that may include a third set of conductive leads <NUM>. Each of the conductive leads of the first set <NUM> may be formed by a seventh set of channels <NUM>. The third set of conductive leads <NUM> may include a third conductive lead <NUM> and a fourth conductive lead <NUM>. In one or more embodiments, the third conductive lead <NUM> may be connected to the second conductive strip <NUM> and the fourth conductive lead <NUM> may be connected to the conductive strip disposed closes to the first side <NUM>. The fourth conductive lead <NUM> may have a length that is less than a length of the third conductive lead <NUM>.

The third set of conductive leads <NUM> may be formed by an eighth set of channels <NUM> and may include a first conductive lead <NUM> and a second conductive lead <NUM>. The first conductive lead <NUM> may be connected to the third conductive lead <NUM> and the second conductive lead <NUM> may be connected to the fourth conductive lead <NUM>. The first conductive lead <NUM>, the second conductive lead <NUM>, and the conductive leads disposed therebetween may each include end portions that may be positioned substantially orthogonal to the third conductive lead <NUM>, the fourth conductive lead <NUM>, or both.

In one or more embodiments, the conductive leads <NUM>, <NUM> and the conductive leads <NUM>, <NUM>, each of the first portion <NUM>, may have a width that is less than a width of the conductive leads <NUM> and conductive leads <NUM> of the second portion <NUM>.

During operation of the pressure sensing mat <NUM>, voltage may be applied through the conductive leads <NUM>, <NUM>, <NUM> to the conductive leads <NUM>, <NUM>, <NUM>, and to the conductive strips <NUM>, <NUM>, <NUM>, <NUM>. With the applied voltage, the capacitors <NUM> may be formed between the first portion <NUM> and the second portion <NUM>. Capacitance measurements from each of the capacitors <NUM> may be made by processor <NUM> through one or more of the conductive strips <NUM>, <NUM>, <NUM>, <NUM> to the adjoining conductive leads <NUM>, <NUM>, <NUM> and to the conductive leads <NUM>, <NUM>, <NUM>.

<FIG> illustrates an exploded view of either the first portion <NUM> or the second portion <NUM> prior to forming (e.g., etching) the channels. The non-conductive layer <NUM>, <NUM> positioned above the conductive layer <NUM>, <NUM>, may be layered and adhered to a top surface of the conductive layer <NUM>, <NUM> and the non-conductive layer <NUM>, <NUM> may be layered and adhered to a bottom surface of the conductive layer <NUM>. The non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may be permanently assembled to the conductive layer <NUM>, <NUM> by applying heat, pressure, welding, adhesive, or some combination thereof.

In one or more embodiments, the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may be smaller than the conductive layer <NUM>, <NUM>. In other words, a surface area of the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may be smaller than a surface area of the conductive layer <NUM>, <NUM>. Because the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> have a smaller surface area than the surface area of the conductive layer <NUM>, <NUM>, a portion of the conductive layer <NUM>, <NUM> may be exposed. The exposed portions may be referred to as a first bare bar <NUM> (<FIG>) in the first portion <NUM> and a second bare bar <NUM> in the second portion <NUM> (<FIG>). The first bare bar <NUM> and the second bare bar may be used to test one or more electrical properties of the first portion <NUM> and the second portion <NUM>.

As an example, the electrical measurement devices may engage one or more of the bare bars <NUM>, <NUM> to measure resistance, conductivity or other electric characteristic of the conductive layers <NUM>, <NUM>. The bare bars <NUM>, <NUM> may be positioned near a periphery of the first and second portions <NUM>, <NUM>, respectively. Positioning the bare bars <NUM>, <NUM> near the periphery may provide measurement points without disassembling the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> from the conductive layers <NUM>, <NUM>.

<FIG> illustrates a partial-perspective view of the pressure sensing mat <NUM>. To better portray the layers of the mat, a corner of the pressure sensing mat <NUM> is fanned out to show at least some of the layers of the pressure sending mat <NUM>.

<FIG> illustrates a partial cross-sectional view of the pressure sensing mat <NUM> taken along the lines 7A in <FIG> and <FIG> illustrates a partial cross-sectional view of the pressure sensing mat <NUM> taken along the lines 7B in <FIG>. <FIG> are each magnified to better illustrate the layers of the mat. As illustrated the covers <NUM> may each form the top and bottom surfaces of the mat. As previously mentioned, the covers <NUM> may not be used for all configurations of the mat <NUM>. The covers <NUM> may lie along the first non-conductive layers <NUM> and the fourth non-conductive layer <NUM>, respectively.

The first conductive layer <NUM> and the second conductive layer <NUM> may each be at least partially formed of a conductive metal or alloy material. As one example, the conductive layers <NUM>, <NUM> may each be formed by a laminated copper material, such as <NUM> copper laminated. The laminated copper material may have a thickness ranging between <NUM> microns and <NUM> microns. As one example, Table <NUM> provides material properties of the <NUM> copper laminated material. In one or more embodiments, the conductive layers <NUM>, <NUM> may each be formed of or include silver, aluminum, or other suitable conductive materials.

The first and second non-conductive layers <NUM>, <NUM> may be laminated to the first conductive layer <NUM> and the third and fourth non-conductive layers <NUM>, <NUM> may be laminated to the second conductive layer <NUM>. As an example, the conductive layers <NUM>, <NUM> may be coated by a non-conductive film. As another example, the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may each be composed of a plastic or polymeric material such as a thermoplastic polyurethane (TPU), or polyethylene terephthalate (PET), or some combination thereof. One or more of the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may have a thickness that is approximately half of the thickness of the copper material. For example, the copper material may have a thickness of <NUM> microns while the thickness of the non-conducive layers <NUM>, <NUM>, <NUM>, <NUM> may have thickness of <NUM> microns.

The thickness of the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may be increased to provide a number of advantages. As an example, increasing the thickness of the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may prevent tearing or cracking of the conductive layers <NUM>, <NUM>, to increase the durability and the useful life of the mat <NUM>. As another example, the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> having a thickness in the range mentioned above may prevent or reduce noise associated with the copper material moving as the occupant moves along the mat. Much like a bag of chips or other food packaged in a metallic foil, the conductive layers <NUM>, <NUM>, without the non-conductive layers tend to generate noise as the occupant moves on the mat. This noise may be an annoyance for the patient or another positioned near the mat. One or more of the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> may mitigate this noise.

The insulative layer <NUM> may be sandwiched between the first portion <NUM> and the second portion <NUM> and may have a thickness that may be exponentially greater than the thickness of the first or second portions <NUM>, <NUM>. As an example, the insulative layer <NUM> may have a thickness that ranges between <NUM> to <NUM>.

Each of the channels <NUM>, <NUM> may have a width ranging between <NUM> and <NUM>. As the width of the channels increases, the size of pixels may increase. In one or more embodiments, the channels <NUM>, <NUM> may extend through at least one of the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> of each portion <NUM>, <NUM> and through the conductive layers <NUM>, <NUM>. In one or more embodiments, the surface defining the channels <NUM> may lie along the insulative layer <NUM> instead of being layered with the uppermost cover <NUM>. Such a position may provide a waterproof or at least a water-resistant barrier between the outermost portions of the matt <NUM> and the conductive layer <NUM>.

While the cross-sectional views of <FIG> only illustrate the first set of channels <NUM> that form the third conductive strip <NUM> and the second set of channels <NUM> the form the fourth conductive strip <NUM>, the configurations illustrated equally apply to the other channels that form the sets of signal detecting leads, signal receiving leads, and other conductive strips.

The channels <NUM>, <NUM> may be formed by a laser etching process. The process may include providing and extending the laminated conductive material along a work surface. The laminated conductive material may be pre-cut to a predetermined size and shape or the laminated material may be a portion of a coil of the laminated conductive material. The laminated conductive material may be fixtured or held in place by a number of vacuums disposed along the work surface. The suction devices may be configured to apply a predetermined pressure of vacuum so that the laminated conductive material is held relatively flat across the work surface. One or more lasers may then be applied to remove or etch the laminated conductive material to form the channels. As another example, one of the lasers may cut portions of the laminated conductive material from the coil or cut peripheral portions of the material to a required length and width.

The width, length, position and depth of the channels may be measured by a coordinate measuring machine or other suitable measurement device. As another example, electrical resistance across a number of sections or an entirety of a test sample of one of the portions <NUM>, <NUM> may be measured. The measured electrical resistance of the tested sample may be compared to a master sample having a known electrical resistance. The resistance measurement device may be attached to a portion of the conductive layer <NUM>, <NUM> that is not covered or laminated by non-conductive layers <NUM>, <NUM>, <NUM>, <NUM>.

As an example, the laser be a fiber laser system a CO<NUM> laser system, or another suitable laser system. The laser beam may move across the laminated conductive material between two or more known reference coordinates at a number of velocities. As the beam of the laser approaches a predetermined position requiring a change in direction, the velocity of the laser may be decreased. However, as the velocity of the laser decreases, a number of adjustments may be required including but not limited to the power or focal point of the laser.

<FIG> illustrates a detailed view of a portion of the pressure sensing mat. The top and bottom covers <NUM> are shown as curled away from the first portion <NUM> and the second portion <NUM>. The first portion <NUM> and the second portion <NUM> are each shown as curled away from the insulative layer <NUM>. For purposes of clarity, the non-conductive layers <NUM>, <NUM>, <NUM>, <NUM> are not shown curled away from the conductive layers <NUM>, <NUM>.

<FIG> illustrates a perspective view of an exemplary connector. As one example, the connector may be a flat flex connector <NUM>. The connector <NUM> may include a housing <NUM> and a number of connector leads that may be fixed to the signal receiving leads of the first and second portions <NUM>, <NUM>.

<FIG> illustrates a perspective view of another exemplary connector. As one example the connector may be a flexible printed circuit connector <NUM>. The connector <NUM> may include a number of leads <NUM> that may be disposed on a substrate <NUM>. The leads may include a number of connection points <NUM> that may be fixed to the signal receiving leads of the first and second portions <NUM>, <NUM>.

Claim 1:
A pressure sensing mat (<NUM>) comprising:
a first portion (<NUM>) including a first conductive layer (<NUM>) contacting a first non-conductive layer (<NUM>), wherein the first conductive layer (<NUM>) is continuous except for a first plurality of discontinuities (<NUM>) defining a first plurality of conductive strips (<NUM>) oriented in a first direction, wherein the first portion includes a first end (<NUM>) and a second end (<NUM>), wherein each conductive strip of the first plurality of conductive strips (<NUM>) are formed as columns including first and second columns, wherein the first column has a first width and is spaced apart from the first end by a first distance and the second column has a second width greater than the first width and is spaced apart from the first end by a second distance, greater than the first distance;
a second portion (<NUM>) including a second conductive layer (<NUM>) layered to a second non-conductive layer (<NUM>), wherein the second conductive layer (<NUM>) is continuous except for a second plurality of discontinuities (<NUM>) defining a second plurality of conductive strips (<NUM>) oriented in a second direction; and
an insulative layer (<NUM>) disposed between the first portion (<NUM>) and the second portion (<NUM>), wherein the first plurality of conductive strips (<NUM>) and the second plurality of conductive strips (<NUM>) form a conductive strip matrix having a plurality of capacitors wherein each capacitors of the plurality of capacitors (<NUM>) are configured to provide a capacitance indicative of a pressure applied at each capacitor of the plurality of capacitors (<NUM>).