JP7518851B2 - Apparatus and method for detecting visual impairment configurations - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No. 16/360,913, filed Mar. 21, 2019, and entitled "Apparatus and Method for Detecting Visually Impaired Configurations," the disclosure of which is incorporated herein by reference in its entirety.

The present disclosure relates generally to an apparatus for detecting the presence of a difficult-to-see structure behind an opaque solid surface, and more specifically to an apparatus for locating beams and studs behind walls and joists below floors.

Locating difficult to see features such as beams, studs, joists and other elements behind walls and below floors is a common challenge faced during construction, repair and remodeling activities. For example, a desire often arises to cut or drill into a wall, floor or other supporting surface while avoiding underlying supporting elements to create an opening in the surface. In these instances, it may be desired to know the location of the supporting element before beginning in order to avoid cutting or drilling into the supporting element. In other cases, it may be desired to fasten a heavy object such as a painting or shelf to a supporting element by the supporting surface. In these instances, it may often be desired to attach a fastener that penetrates the supporting surface that is aligned with the underlying supporting element. However, the presence of the wall, floor or supporting surface in a fixed location makes it impossible to visually detect the location of the supporting element.

A variety of basic techniques have been employed in the past with limited success to address the problem of locating underlying structures obscured by an overlying surface. These techniques include driving a small pivoting claw through the overlying surface until an underlying support element is encountered, and then creating a hole in the surface that does not indicate the location of the underlying support element. A less destructive technique involves tapping the overlying surface to detect an audible change in the sound emanating from the surface when a support element is present below or behind the area of the surface being tapped. However, this technique is ineffective because the accuracy of the results is highly dependent on the judgment and skill of the person tapping and listening to locate the underlying support element, and because the sound generated by the tapping is highly sensitive to the type and density of the surface being tested.

Magnetic detectors have also been employed to locate hard-to-see support elements, with the detector relying on the presence of metal fasteners, such as nails and screws, in the walls and support elements to trigger a detector response. However, because the metal fasteners are spaced at discrete locations along the length of the support, the magnetic detector may pass over a length of the support where no fasteners are located, thereby failing to detect the presence of hard-to-see support elements.

Electrical sensors have also been employed to detect difficult-to-see structures behind opaque surfaces. These detectors sense changes in capacitance of the surface being tested due to the presence of structures located behind, under, or within the surface being tested. These capacitance changes are detectable across a variety of surfaces, such as wood, sheetrock, stucco, gypsum, etc., and do not rely on the presence of metal fasteners within the surface or difficult-to-see structures for sensor activation. However, conventional electrical detectors can suffer from significant shortcomings. Conventional difficult-to-see structure detectors can have difficulty accurately compensating for the thickness and density of the surface being detected, which adversely affects accuracy.

The present disclosure advantageously addresses one or more of the above-mentioned deficiencies in the field of detecting difficult to see structures by providing a difficult to see structure detector that is accurate, simple to use, and inexpensive to manufacture. The detector can be used by placing a device against a surface to be tested and reading the location of all structures present below the surface on which the device is placed. The detector can accurately indicate across a variety of surface materials and thicknesses of the surface.

Additional aspects and advantages will become apparent from the following detailed description of the preferred embodiments, which proceeds with reference to the accompanying drawings.

FIG. 13 illustrates an advanced hard-to-see configuration detector positioned on a portion of sheetrock to detect hard-to-see configurations, according to one embodiment. FIG. 2 is a perspective view of the low vision configuration detector of FIG. 1; 2 is a diagram showing the sensor plate of the hard-to-see-configuration detector of FIG. 1 and an activated indicator that signals the location of a hidden hard-to-see-configuration. FIG. 2 is a diagram of a circuit of a hard-to-see configuration detector according to one embodiment. FIG. 2 is a diagram of a controller of a hard-to-see configuration detector according to one embodiment. 1 is a cross-sectional view of a low-vision configuration detector including a housing, with a light pipe and button, and a printed circuit board, according to one embodiment. FIG. 2 is a diagram of a prior art low-vision detector disposed on a relatively thinner surface. FIG. 2 is a diagram of a prior art low-vision detector disposed on a relatively thicker surface. FIG. 2 is a side view of a prior art low-vision detector showing the main sensing field zones for several sensor plates; FIG. 2 illustrates a bottom front view of a prior art low-vision detector, showing the main sensing field zones for several sensor plates. 1 is a flow diagram of a method for detecting low vision configurations behind a surface according to one embodiment. FIG. 1 is a diagram of a prior art plate configuration for a hard-to-see detector with a common plate. FIG. 13 is a diagram of the plate configuration for a hard-to-see detector with a shortened common plate. FIG. 13 illustrates the electric field lines for the prior art plate configuration of FIG. FIG. 14 illustrates the electric field lines for the plate configuration of FIG. 13. FIG. 13 illustrates electric field lines for a sensor plate array having multiple common plates. 1 is a flow chart illustrating a method for detecting difficult-to-see configurations behind a surface with a plate configuration with a shortened ground plane, according to one embodiment. FIG. 13 shows the electric field lines for a sensor plate array with narrow end plates. FIG. 13 illustrates electric field lines for a sensor plate array having trapezoidal end plates. FIG. 13 illustrates a hard-to-see configuration detector positioned on a portion of sheet rock to detect hard-to-see configurations, according to one embodiment. FIG. 21 is a perspective view of the low vision configuration detector of FIG. 20 . FIG. 21 illustrates the sensor plate of the hard-to-see-feature detector of FIG. 20 with an activated indicator that signals the location of a hidden hard-to-see feature. FIG. 2 is a diagram of a circuit of a hard-to-see configuration detector according to one embodiment. FIG. 2 is a diagram of a controller of a hard-to-see configuration detector according to one embodiment. 1 illustrates the routing of sensor plate traces for a low-vision configuration detector according to one embodiment, in the illustrated embodiment, each of the multiple sensor plate traces has a substantially similar trace length, and the traces are surrounded by active shielding. FIG. 13 is a diagram of a sensor plate configuration of a low vision configuration detector according to another embodiment. 1 is a cross-sectional view of a low-vision configuration detector including a housing, with a light pipe and a button and a printed circuit board, according to one embodiment. FIG. 2 shows a sensor plate group having four sensor plates. FIG. 2 shows a sensor plate group having six sensor plates. FIG. 2 is a diagram of a prior art low-vision detector disposed on a relatively thinner surface. FIG. 2 is a diagram of a prior art low-vision detector disposed on a relatively thicker surface. FIG. 2 is a side view of a prior art low-vision detector showing the main sensing field zones for several sensor plates; 1 depicts a bottom front view of a prior art low-vision detector showing the main sensing field zones for several sensor plates; FIG. 1 is a side view of a chassis of a core device of a surface-matched low-vision configuration detector according to one embodiment. FIG. 35 is a perspective view of the chassis of the core device of FIG. 34. 1 is a flow diagram of a method for detecting low vision configurations behind a surface according to one embodiment. FIG. 1 illustrates two different printed circuit boards in a stacked configuration. FIG. 1 illustrates a prior art arrangement for routing sensor plate traces from a controller to a sensor plate and protecting the sensor plate traces. FIG. 2 is a cross-sectional view of a low-vision configuration detector according to one embodiment, showing the electric field pattern. FIG. 13 is a cross-sectional view of a low-vision configuration detector according to another embodiment, showing the electric field pattern. FIG. 2 is a diagram of a sensor plate cluster including an active shielding core, eight sensor plates, an active shielding plate, and a common plate. FIG. 2 is a diagram of a sensor plate cluster including an active shielding core, eight sensor plates, and an active shielding plate. FIG. 43 is a side view of a low-vision configuration detector including a sensor plate cluster similar to the sensor plate cluster depicted in FIG. 42, disposed on a surface, according to one embodiment. FIG. 1 is a diagram of a sensor plate cluster including eleven sensor plates, an active shield plate, and a common plate, where the edge sensor plates have a smaller area than the sensor plates not present at the edges. FIG. 45 is a side view of a low-vision configuration detector including a sensor plate cluster similar to the sensor plate cluster depicted in FIG. 44, disposed on a surface, according to one embodiment. FIG. 13 is a side view of a low-vision configuration detector disposed on a surface, according to another embodiment. 1 is a diagram of a plate configuration for a low vision configuration detector according to an embodiment of the present disclosure. 1 is a diagram of a plate configuration for a low vision configuration detector according to an embodiment of the present disclosure. 1 is a diagram of a plate configuration for a low vision configuration detector according to an embodiment of the present disclosure.

In the following description, reference is made to the accompanying drawings, which form a part hereof. The drawings are presented to illustrate certain exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the techniques and embodiments described herein, with the understanding that the various disclosed embodiments can be modified and other embodiments can be used without departing from the spirit and scope of the disclosure. Therefore, the following detailed description is not to be taken in a limiting sense.

Many currently available stud detectors (e.g., stud detectors) use capacitance to detect studs behind a surface. Capacitance is an electrical quantity of an object's ability to hold or accumulate charge. A common form of energy storage device is a parallel plate capacitor, whose capacitance is approximately equal to the equation C = εr εo A/d, where A is the overlapping area of the parallel plates, d is the distance between the plates, εr is the static relative permittivity (or dielectric constant of the material between the plates), and εo is a constant. Dielectric materials are electrical insulators that can be polarized by applying an electric field. When an insulator is placed in an electric field, the molecules are displaced from their average equilibrium positions, causing dielectric polarization. Due to dielectric polarization, positive charges move toward the negative edge of the electric field and negative charges move in the opposite direction.

The dielectric constant of air (εr) is 1, while most rigid non-conductive materials have a dielectric constant greater than 1. In general, the dielectric constant at which conventional capacitance sensors can function is the variation of the dielectric constant of the non-conductive material solids.

When the sensor plate on the low-vision configuration detector is placed in a position on a wall where there is no support behind the wall, the detector measures the capacitance between the wall and the air behind the wall. When the detector is placed in a position where there is a support behind the wall, the detector measures the capacitance between the wall and the support behind it. The support has a higher dielectric constant than air. As a result, the detector indicates an increase in capacitance, which can then be used to activate an indication system.

Currently available hard-to-see detectors typically have a set of identical sensor plates arranged in a linear fashion (see, for example, FIG. 10). Each of the sensor plates takes a sensor reading for a surface. The sensor readings are then compared. The sensor plate with the highest sensor reading is determined to be at the location of the hard-to-see structure. However, sensor plates near the edge of the group may not respond to the hard-to-see structure in the same way as sensor plates near the center. This problem may be particularly evident when the hard-to-see detector moves from a thinner surface to a thinner or less dense surface to a thicker or more dense surface.

Ideally, in the absence of a hard-to-see feature, the sensor plates on the thicker surface would have similar sensor readings to each other since they are all on the same surface. However, the sensor readings of the sensor plates near the edges may produce higher readings than the sensor plates near the center. The sensor plates at the edges are isolated when creating an electric field above the group of sensor plates. As a result, the sensor plates near the edges may respond with disproportionately high readings when placed on the thicker surface. Thus, it may be difficult for the controller to determine whether the sensor reading is high due to the presence of a hard-to-see feature or because the detector is placed on a thicker surface. The present disclosure provides a solution.

In a low-vision configuration detector having multiple sensor plates, it is desirable for each sensor plate to have a similar response to the same low-vision configuration. To ensure similar responses from each sensor plate, appropriate geometry and placement of the sensor plates can ensure equal response to low-vision configurations. Improving shielding of the sensor plate traces can also improve performance. Additionally, improving electrical coupling of the user to the sensing circuitry can improve performance. A mechanism that ensures that the sensor plate is flat relative to the surface can also improve performance.

The present disclosure is directed to a low-vision configuration detector and a method for detecting a low-vision configuration detector. In an exemplary embodiment, the low-vision configuration detector includes a group of sensor plates, a multi-layer printed circuit board (PCB), sensing circuitry, a controller, a display circuitry, a power controller, and/or a housing.

The disclosed embodiments facilitate maintaining uniform or nearly uniform electric field lines generated by a group of sensor plates. Specifically, the electric fields of the two end sensor plates in a group of sensor plates are substantially similar to the electric fields of the non-end sensor plates. The electric fields generated by the end and non-end sensor plates can be oriented transverse to one another.

The disclosed embodiments allow for more accurate identification of the location of difficult-to-see features. The disclosed embodiments also allow for instantaneous and accurate readings across a variety of surfaces having different dielectric constants. Additionally, the currently disclosed embodiments improve the ability to instantaneously and accurately read across different surface thicknesses.

The disclosed embodiments also create a detector that is easier to use. Many prior art detectors require more steps, more time, and more skill to realign the unit to various surfaces to measure the position of difficult-to-see features. The disclosed embodiments provide more reliable sensor readings. The sensor reading from the sensor plate has the ability to self-adjust to the surface being detected to provide more reliable readings and detect features deeper. Surface thickness induced reading errors in the sensor reading are significantly reduced. By eliminating reading errors in this way, the disclosed embodiments can detect objects deeper.

In some embodiments, it may be desirable for each sensor plate in a set of sensor plates to have a response similar to that of the other sensor plates. For example, in one embodiment, it may be desirable for the response from each sensor plate in a group of sensor plates to be similar to the response from each other sensor plate in the group. In some embodiments, similar response may mean that when a hard-to-see feature detector is placed on or against a first surface and readings are recorded to form a first set of readings, and a hard-to-see feature detector is placed against a second surface (e.g., a thicker surface, a denser surface, etc.) and a second set of readings is recorded, the difference between the first set of readings and the second set of readings may be similar for each of the corresponding sensor plates.

Otherwise, each of the sensor plates of an embodiment of the hard-to-see configuration detector can generate a similar reading when placed against a first surface and away from any support structure. For example, the reading can be 100. Then, if the hard-to-see configuration detector is placed against another surface away from the support structure, etc., and has a different, e.g., density, thickness, dielectric constant, etc., each sensor plate of the hard-to-see configuration detector can generate a similar value, such as 150, and the difference in values generated by each sensor plate can be 50, such that the difference in values generated by each sensor plate of the sensor plate group is essentially equal in the absence of the hard-to-see configuration (e.g., support structure, etc.). Thus, any variation in the values (or difference in values) generated by the group of sensor plates can be attributed to the presence of the hard-to-see configuration (e.g., support structure, etc.).

In a typical embodiment, the presence of a support structure, e.g., a framework stud, behind the surface on which the low-visibility detector is placed can result in distinct differences in the readings of each sensor plate that overlays the support structure behind the surface. For example, a first sensor plate that detects a framework stud behind the surface can generate an increase in reading of, e.g., 50. Each sensor plate that passes through or overlies the framework stud can similarly generate an increase in reading of similar magnitude. Furthermore, each sensor plate can generate a similar degree of change while a particular sensor plate is over the support structure. Furthermore, support structures having different properties, e.g., density, thickness, material, etc., can generate characteristic changes, and each such characteristic change can be similar for each sensor plate. Thus, the low-visibility detector can be useful both in identifying the presence of a support structure and, to some extent, in distinguishing between support structures that have substantial differences. For example, steel provides a much stronger signal than wood, and in some embodiments, it is possible to distinguish between wood and steel.

The sensor plates of an embodiment may have a rectangular, trapezoidal, triangular, or complex geometric shape (e.g., asymmetric, irregular) to generate a more uniform sensor field among the multiple sensor plates in the sensor plate group. In other words, the shape of each sensor plate in the sensor plate group may be formed to generate a similar signal response in each sensor plate in the sensor group. The asymmetric or irregular shape of at least some of the sensor plates may allow for achieving a similar response across each of the sensor plates by allowing better tuning for a more similar response. For example, in an embodiment where the sensor plate group includes multiple sensor plates arranged generally in a row, the sensor plates near the center of the row may be of a uniform (or nearly uniform) rectangular shape, while each sensor plate successively distal to either side of the central rectangular sensor plate may take on a different shape to "tune" the signal field across the collection of sensor plates to be more uniform than would result from using a single geometric shape exclusively for all of the sensor plates. The preferred shape of each sensor plate, and the preferred configuration of the assembly of sensor plates in a sensor plate group, may be identified through prototype testing by methods known to those skilled in the art, including physical prototype testing and computer-based simulation testing.

For example, the shape of the sensor plate may be determined by testing physical prototypes by cutting sensor plates of various shapes and testing them. To find the desired sensor plate shape, various shapes can be tested in various conditions, such as with various surface thicknesses and on surfaces with various dielectric constants. The results of the various tests may then need to be compared to determine the magnitude of variation in the sensor plate readings. In some embodiments, a sensor plate design that minimizes the variation in readings across the various test conditions can be selected. While the process of testing physical prototypes to determine an ideal sensor plate design can be effective, in some embodiments it can be unusually taxing.

Simulation testing is another example of how to determine the sensor plate geometry. In some embodiments, the sensor plate geometries may be determined by simulating them in software, such as by simulating electrostatic fields using finite element analysis software. Other approaches to analyzing the fields to determine the plate geometry may include Method of Moments (MoM) approaches, Finite Difference Time Domain (FDTD) approaches, etc. Available software can be used to perform these functions. As a non-limiting example, finite element analysis can be used to find the sensor plate geometry that provides the most similar response across all of the target conditions.

In some embodiments, different simulation models can be constructed to represent different target conditions. For example, it may be beneficial to run models with three different surface thicknesses, each with three different dielectric constants, which would total nine different models. In this way, nine different target conditions can be tested. Each model may be tested individually to determine the simulated readings on the sensor plate. The results of the various simulation tests can then be compared to determine the magnitude of the change in the sensor plate readings. In some embodiments, a sensor plate design that minimizes the change in readings can be selected. Various sensor plate geometries may be tested to determine a design that minimizes the change in the sensor plate readings across each of the target conditions.

In some embodiments, one approach to prototyping and/or simulation testing may be to split the sensor plate into multiple parts and then simulate each part independently. Those skilled in the art will appreciate that the concept of superposition may be relied upon to combine the fields resulting from the parts by adding the fields together to obtain a total resulting field.

Prototyping and/or simulation testing can be used to identify an ideal shape (potentially including thickness and/or components) of the sensor plate and an ideal configuration of the sensor plate that, when used for the identified low vision configuration, will produce a uniform or near uniform and consistent signal response.

The present disclosure will now be described more fully with reference to the accompanying drawings. However, the present disclosure can be embodied in many other different forms. The present disclosure should not be construed as being limited to the embodiments described herein, but rather, these embodiments are provided solely to fully convey the full scope of the present disclosure to those skilled in the art.

Figure 1 shows a hard-to-see configuration detector 1 positioned on a portion of sheet rock 2 (or a similar surface) to detect hard-to-see configurations 3, according to one embodiment. Figure 2 is a perspective view of the hard-to-see configuration detector 1 of Figure 1. Figure 3 shows a sensor side of the hard-to-see configuration detector 1, including multiple sensor plates 5 and a shortened common plate 33.

Referring to Figures 1-3, generally and generally, the low vision configuration detector 1 includes three or more sensor plates 5, sensing circuitry (see Figure 4), one or more indicators 6, one or more proximity indicators 39, and a housing 19 that provides or houses a handle 14, an active shield plate 23, and a battery cover 28.

The three or more sensor plates 5 can each obtain a sensor reading that varies based on the proximity of the sensor plate 5 to one or more surrounding objects and the material properties of each of the one or more surrounding objects. The three or more sensor plates 5 can collectively produce a sensing field. Each individual sensor plate 5 of the three or more sensor plates 5 can produce a corresponding primary sensing field zone, which can be a three-dimensional geometric volume within the sensing field in which the individual sensor plate 5 contributes more strongly to the sensing field than any other of the three or more sensor plates 5. The three or more sensor plates 5 can all produce geometrically similar primary sensing field zones. A sensing circuit can be coupled to the three or more sensor plates 5 to measure the sensor readings of the three or more sensor plates 5.

Each sensor plate 5 forms a first end of a corresponding electric field. The electric field is generated or received at the sensor plate 5. A region of the common plate 33 can form a second end of the corresponding electric field for each sensor plate 5. The common plate 33 has a length that extends along one side of each sensor plate 5. The length of the common plate 33 is less than the overall length dimension of the sensor plate 5. In some embodiments, the common plate 33 is connected to a constant voltage. In some embodiments, the common plate 33 is connected to a circuit ground. In some embodiments, the common plate 33 is connected to an alternating signal.

In some embodiments, each sensor plate 5 may be part of a group 7 or array of sensor plates 5. Each group 7 may include more than one sensor plate 5 and may also include an active shield plate 23. The sensor plate 5 and the active shield plate 23 may be on different planes. Nevertheless, in some embodiments, the sensor plate 5 and the active shield plate 23 may be part of the same group 7 of sensor plates 5 if they are driven simultaneously. Each sensor plate 5 has a geometric shape defined by its shape. Each sensor plate 5 also has a perimeter. In some embodiments, the perimeter may be made up of multiple parts. In some embodiments, each part of the perimeter is an inner boundary 10 or an outer boundary 11. In some embodiments, if the sensor plate 5 has a part of its perimeter that is adjacent to the perimeter of the group 7, the part includes the outer boundary 11. In some embodiments, if the sensor plate 5 has a part of its perimeter that is not adjacent to the perimeter of the group 7, the part includes the inner boundary 10.

In an embodiment for sensing the position of the hard-to-see configuration 3, a current source can be used to drive the sensor plate 5 and the hard-to-see configuration detector 1 measures the time it takes for the sensor plate 5 to reach a threshold voltage, thereby obtaining a sensor reading. In other embodiments, a charge share mechanism or a sigma-delta converter is used to obtain the sensor reading. Other sensing circuits can also be employed. In other embodiments, a radio frequency signal is placed on the sensor plate 5 to obtain the sensor reading. In each of these embodiments, the signal driven on the sensor plate 5 is sensed.

In some embodiments, only one sensor plate 5 can be actuated at a time. In these embodiments, a single sensor plate 5 can be isolated when producing a sensing field.

In some embodiments, the group 7 of sensor plates 5 can all be driven simultaneously with the same signal. In these embodiments, the group 7 of sensor plates 5 can produce a sensing field. In some embodiments, multiple sensor plates 5 can each be driven simultaneously with the same signal, or only a single sensor plate 5 can be sensed. Advantageously, driving multiple sensor plates 5 simultaneously can produce field lines that go deeper into the poor vision configuration than driving only a single sensor plate 5. Deeper field lines allow for deeper sensing. In some embodiments, the group 7 of sensor plates 5 and the active shielding plate 23 can all be driven simultaneously with the same signal, and the group 7 of sensor plates 5 and the active shielding plate 23 can produce a sensing field together.

Each sensor plate 5 has a primary sensing field zone. In some embodiments, the primary sensing field zone is a three-dimensional geometric volume of the sensing field and associated field lines to which an individual sensor plate 5 is more sensitive than the active shield plate 23 (if present) or any other sensor plate 5. In some embodiments, it is desirable for each sensor plate 5 to have similar primary sensing field zones. In some embodiments, it is desirable for each sensor plate 5 to have geometrically similar primary sensing field zones and similar sensing fields within each primary sensing field zone.

Figure 3 shows 13 sensor plates 5 arranged in a linear fashion to form a sensor array 7. Each of the sensor plates 5 is rectangular. Each sensor plate is configured to obtain a sensor reading that varies based on the proximity of the sensor plate 5 to one or more surrounding objects and the material properties of each of the one or more surrounding objects.

In some embodiments, as depicted in FIG. 3, the sensor array 7 may include sensor plates 5 each having a similar geometric shape. In some embodiments, the distance between adjacent sensor plates 5 may be approximately 2.0 millimeters. As shown, a shortened common plate 33 extends along the sensor array 7 along one side of each sensor plate 5. The length of the shortened common plate 33 is less than the overall length dimension of the sensor array 7. In some embodiments, the shortened common plate 33 may not extend along the side of one or both end sensor plates.

In FIG. 3, the sensor plates 5 can collectively produce a sensing field. In some embodiments, the active shielding plate 23 can contribute to the sensing field. In the embodiment of FIG. 3, each sensor plate 5 can have a similar primary sensing zone. In this embodiment, the shortened common plate 33 causes each sensor plate 5 to have a primary sensing field zone that is more geometrically similar to the primary sensing field zone described in more detail with reference to FIGS. 12, 15, and 16. Similarly, each sensor plate 5 can also have a similar sensing field within each primary sensing field zone. As a result, a low-vision configuration detector 1 assembled with the configuration of FIG. 3 can provide improved performance. When the low-vision configuration detector 1 moves from a thin surface to a thicker surface, the sensor readings for each of the sensor plates 5 can have a similar increase in value.

In some embodiments, a sawtooth shaped edge or border can have the same effective edge as a straight edge without sawtooth. In some embodiments, an edge with a very thin curve can have the same effective edge as a straight edge without a thin curve. In some embodiments, a sensor plate 5 with a slot therein has the same effective geometry as a different equivalent sensor plate 5 without a slot. In some embodiments, a sensor plate 5 with a small hole therein can have the same effective geometry as an equivalent sensor plate 5 without a hole. Many other geometries are possible that can be effectively equivalent to other substantially equivalent geometries. Many other edges are possible that can be effectively equivalent to other substantially equivalent edges. If a geometry or edge has substantially equivalent properties to another geometry or edge, the two may be considered similar.

In one embodiment, the group 7 of sensor plates 5 is configured such that each sensor plate 5 in the group 7 has the same geometric shape. In one embodiment, each sensor plate 5 in the group 7 is radially symmetric.

The multiple indicators 6 can be toggled between inactive and active states to indicate the location of a range of relatively high sensor readings. An activated indicator 4 can indicate the location of the low-vision configuration 3. A proximity indicator 39 can indicate that the low-vision configuration detector 1 can be near the low-vision configuration 3.

In Figures 1-3, the indicator 6 is positioned on a layer above the sensor plate 5. In some embodiments, there may be an active shield plate 23 between the sensor plate 5 and the indicator 6 so that the indicator 6 does not interfere with the function of the sensor plate 5. In some embodiments, it may be desirable to position the indicator 6 on a layer above the sensor plate 5.

In some embodiments, a layer of protective agent is placed on the bottom of the housing of the hard-to-see configuration detector such that there is a layer of protective agent between the surface 2 (e.g., sheet rock) and the hard-to-see configuration detector 1. In some embodiments, the interior of the protective agent is substantially filled so that there are substantially no cavities in the protective agent. In some embodiments, the protective agent is different from felt, Velcro, cloth, or other materials that have cavities inside. The layer of protective agent can help protect the bottom of the hard-to-see configuration detector 1 from damage due to knocks, bumps, and abrasion. The protective agent can be made from a solid piece of material such as plastic or other non-conductive solid material. A solid layer of plastic can provide a low-friction surface on which the hard-to-see configuration detector 1 can slide across a wall. Although some embodiments of the hard-to-see configuration detector 1 do not require sliding operation, a low-friction surface can be beneficial to a user who may choose to move the position of the hard-to-see configuration detector 1 by sliding the hard-to-see configuration detector 1.

The protective layer of plastic can be applied by pressure sensitive adhesive, glue or other means. The layer of protective agent can be a complete layer covering the entire surface, or it can be another layer of plastic with a rectangular strip, a round piece or other geometric shape.

The protective agent, which is substantially filled to substantially eliminate voids, may generate less static charge than prior art solutions, which may advantageously provide more consistent sensor readings.

In one embodiment, the protective layer is UHMW-PE (ultra-high molecular weight polyethylene). Ultra-high molecular weight polyethylene has a low coefficient of friction. It also does not absorb much moisture, which may result in increased immunity from changes in humidity.

Figure 4 is a diagram of a circuit of a visually impaired configuration detector 1 according to one embodiment. The circuit includes a multiplexer 18, a power controller 20, a display circuit 25, a sensing circuit 27, and a controller 60.

The power controller 20 may include a power source 22 and an on-off button 24. The power source 22 may include an energy source for powering the indicator 6 as well as powering the capacitance-to-digital converter 21 and the controller 60. In some embodiments, the power source 22 may include a DC battery supply. The on-off switch 24 may be used to activate the controller 60 and other components of the low-vision configuration detector 1. In some embodiments, the on-off switch 24 includes a push button mechanism that activates the components of the low-vision configuration detector 1 for a selected period of time. In some embodiments, the push button activates the components and keeps them activated until the push button is released. In some embodiments, the on-off switch 24 includes a capacitance sensor that can sense the presence of a finger or thumb on the button. In some embodiments, the on-off switch 24 may include a toggle switch or other type of button or switch.

The display circuitry 25 may include one or more indicators 6 electrically coupled to the controller 60.

The sensing circuit 27 may include a voltage regulator 26 and a capacitance-to-digital converter 21. In one embodiment, as shown in FIG. 4, the sensing circuit 27 includes a plurality of sensors, a voltage regulator 26, and a capacitance-to-digital converter 21. The voltage regulator 26 can be used to adjust the output of the power controller 20 as desired. In one embodiment, the voltage regulator 26 can be located as close as possible to the capacitance-to-digital converter 21 to provide a battery power source 22 to the capacitance-to-digital converter 21. The sensing circuit 27 can be electrically coupled to the controller 60. One or more sensor plate traces 35 or conductive paths on a printed circuit board can connect the individual sensor plates 5 to the capacitance-to-digital converter 21. The connection of the sensor plates 5 to the capacitance-to-digital converter 21 can be made via a multiplexer 18. The multiplexer 18 can individually connect the sensor plates 5 to the capacitance-to-digital converter 21.

In some embodiments, the multiplexer 18 can connect a single sensor plate 5 to the sensing circuitry 27. In some embodiments, the multiplexer 18 can connect two or more adjacent sensor plates 5 to the sensing circuitry 27. In some embodiments, the multiplexer 18 can connect two or more non-adjacent sensor plates 5 to the sensing circuitry 27. In some embodiments, the multiplexer 18 is configured such that the sensing circuitry 27 measures the capacitance of one sensor plate 5. In some embodiments, the multiplexer 18 is configured such that the sensing circuitry 27 measures the aggregate capacitance of two or more sensor plates 5.

Each sensor plate 5 of group 7 can be independently connected to a capacitance-to-digital converter 21 via a multiplexer 18. In one embodiment, group 7 itself consists of a copper layer on a printed circuit board.

In one embodiment, a two layer printed circuit board is configured as sensor plate board 40 (see FIG. 6). In one embodiment, a first layer of sensor plate board 40 includes sensor plate 5 and a second layer of sensor plate board 40 includes a shield. In one embodiment, the shield comprises a layer of copper covering the entire surface of the second layer of the printed circuit board. In one embodiment, the copper layer is covered with a non-conductive layer of solder mask. In one embodiment, holes are present in the solder mask layer. In one embodiment, the holes in the solder mask layer include solder pads suitable for forming solder joints.

In one embodiment, a four layer printed circuit board is formed as an interconnect board with interconnects suitable for connecting circuit components. In one embodiment, the interconnect board is configured with four layers of interconnects suitable for interconnecting the sensing circuit 27, the controller 60, and the display circuit 25. In one embodiment, one side of the printed circuit board is configured for mounting components and a second side of the printed circuit board is configured with solder pads.

In some embodiments, the sensor plate 5 is disposed on a first printed circuit board. In some embodiments, the interconnect circuit is disposed on a second printed circuit board. In some embodiments, the first printed circuit board is bonded to the second printed circuit board.

In some embodiments, there are solder pads on the sensor plate board 40 that are complementary to the solder pads on the interconnect board. In some embodiments, the sensor plate board 40 and the interconnect board can be stacked on top of each other and bonded together. In some embodiments, the bonding agent that bonds the two printed circuit boards together can be solder. In some embodiments, the two printed circuit boards can be bonded together using solder paste. In some embodiments, the two printed circuit boards can be bonded together with solder, and the process of bonding the two printed circuit boards together can be a standard SMT (surface mount technology) process. The standard surface mount technology process can include using a stencil to place the solder paste in the desired location. The standard surface mount technology process can include placing one printed circuit board on top of the other. In some embodiments, pins can be used to ensure proper alignment of the two printed circuit boards. In some embodiments, the final step of the surface mount technology process can involve passing the stacked printed circuit boards through a reflow path.

In one embodiment, the sensor plate 5, shield and circuitry are located on a single printed circuit board. In one embodiment, a six layer printed circuit board is used. In one embodiment, the bottom six layer of printed circuit board is constructed with the sensor plate 5. The fifth layer can be the active shield. The top four layers can connect the balance of the circuitry.

In one embodiment, the sensor plate 5, shield, and circuitry are disposed on a single printed circuit board. In one embodiment, a four-layer printed circuit board is used. The first and second layers of the printed circuit board are configured with interconnect circuitry. In one embodiment, the bottom layer of the four layers of printed circuit board is configured with the sensor plate 5. The third layer can be an active shield.

The printed circuit board can be manufactured from a variety of suitable materials, such as FR-4, FR-406, or more advanced materials used in radio frequency circuits, such as Rogers 4003C. Rogers 4003C and other radio frequency class printed circuit boards can provide improved performance over wider temperature and humidity ranges.

As used herein, the term "module" may describe a unit that may perform any given functionality in accordance with one or more embodiments of the present invention. A module may be implemented using any form of hardware or software, or a combination thereof, such as, for example, one or more processors, controllers 60, application specific integrated circuits (ASICs), programmable logic arrays (PLAs), logic components, software routines, or other mechanisms.

The various processes for reading capacitance and converting the capacitance to a digital value, also known as capacitance-to-digital conversion, are well described in the prior art. The many different methods are not described here, and the reader is referred to the prior art for details of various capacitance-to-digital converter methods. One embodiment uses a sigma-delta capacitance-to-digital converter, such as that incorporated in Analog Devices, Inc.'s AD7747 integrated circuit. One embodiment uses a charge-sharing method of capacitance-to-digital conversion.

In one embodiment, the voltage regulator 26 may comprise an ADP150-2.8 from Analog Devices or an NCP702 from ON Semiconductor, which have very low noise. In one embodiment, the controller 60 may comprise a C8051F317 from Silicon Laboratories or any of a number of other microcontrollers.

When using the native sensor reading of the capacitance-to-digital converter 21 alone, detection of the low-vision configuration 3 may require a high degree of accuracy, and may require greater accuracy than the capacitance-to-digital converter 21 can provide. The native sensor reading is the raw value read from the capacitance-to-digital converter 21, which is the digital output of the capacitance-to-digital converter 21.

In some embodiments, native reads are performed multiple times and the multiple native read results are combined to generate a reading. In some embodiments, native reads are performed multiple times and the multiple native read results are combined using two or more native reads of different configurations to generate a reading. In some embodiments, native reads are performed multiple times and the multiple native read results are aggregated or averaged to generate a reading. In some embodiments, this improves the signal to noise ratio. Each native read may involve the reading of one sensor plate 5. If multiple sensor plates 5 are multiplexed to the capacitance to digital converter 21, a native read may also involve the reading of multiple sensor plates 5. In some embodiments, the multiple native reads are combined to generate a reading.

Summing or averaging multiple native readings can improve the signal-to-noise ratio, but may not reduce the nonlinearity effects of the capacitance-to-digital converter 21. An ideal capacitance-to-digital converter 21 is perfectly linear, meaning that its native sensor reading increases in direct proportion to increases in sensed capacitance. However, many capacitance-to-digital converters 21 are not perfectly linear, and changes in input capacitance may not be exactly proportional to increases in native reading. These nonlinearities can be reduced, but when a high degree of accuracy is desired, it is desirable to implement methods to reduce the nonlinearity effects.

In some embodiments, the adverse effects of nonlinearity can be mitigated by aggregating multiple native reads, with a slightly different configuration for each native read. In some embodiments, native reads are performed using two or more different configurations.

For example, bias current is one parameter that can be varied to produce different configurations. The bias current can be set to standard, standard + 20%, standard + 35% or standard + 50%. Different bias currents will produce different native sensor readings even if all other factors remain constant. Because each native reading has a different value, each native reading can possibly be subject to different nonlinearities. Perhaps instead of summing or multiplying, sensor readings subject to different nonlinearities can be summed or averaged to allow the nonlinearities to partially cancel each other out.

In some embodiments, there are two separate and independent capacitance-to-digital converters 21. In some embodiments, each capacitance-to-digital converter 21 may have a different nonlinearity. By utilizing both capacitance-to-digital converters 21, using the first converter for some of the readings and the second converter for some of the readings, the effect of any single nonlinearity can be mitigated.

In one embodiment, native readings are performed on each sensor plate 5 using 12 different configurations.

After completing the sensor readings, in some embodiments, two different calibration algorithms can be performed: the first is an individual plate calibration that adjusts for variations in individual sensor plates 5, and the second is a surface material calibration that adjusts the sensor reading to match the surface density/thickness. Other embodiments may use only one of these two calibration algorithms. Some embodiments may use the other calibration algorithm. In some embodiments, the calibration algorithms are performed by a calibration module.

In some embodiments, individual plate calibration is used first. With individual plate calibration, each sensor plate 5 can have an individual and unique calibration value. In some embodiments, after obtaining sensor readings, the individual plate calibration value is added or subtracted from each sensor reading. In other embodiments, the individual plate calibration can be performed using multiplication, division, or other mathematical functions. In some embodiments, the individual plate calibration value is stored in non-volatile memory. The individual plate calibration compensates for irregularities in the individual sensor plates 5, and the individual plate calibration is used to compensate for these irregularities. In some embodiments, after performing the individual plate calibration, if the sensor readings of the sensor plate are obtained while the hard-to-see configuration detector 1 is on a surface 2 similar to the surface 2 on which the hard-to-see configuration detector 1 is calibrated, the sensor readings will likely have the same calibration value. For example, if the low vision configuration 3 is not present and sensor readings are taken on ½ inch (½", 12.7 mm) sheetrock 2, producing individual calibration values for the ½ inch sheetrock 2, then after performing the individual board calibration, it is believed that all of the sensor readings can be corrected to a common value. If the sensor readings are taken on a thicker material (e.g., 5/8 inch (5/8") sheetrock 2), a thinner material (e.g., 3/8 inch (3/8") sheetrock 2), or a different material (e.g., 3/4 inch (3/4") plywood), there may be some error in the values. The face material configuration may help correct this error.

In some embodiments, face material configurations can be used.

In one embodiment, after calibrating the sensor readings of the sensor plates, the hard-to-see configuration detector 1 determines whether hard-to-see configuration 3 is present. In one embodiment, the lowest sensor plate reading is subtracted from the highest sensor plate reading. If this difference is greater than a threshold, it is determined that hard-to-see configuration 3 is present.

If it is determined that no hard-to-see configuration 3 is present, all indicators 6 can be deactivated. If a hard-to-see configuration 3 is present, the hard-to-see configuration detector 1 begins the process of determining the position and width of the hard-to-see configuration 3.

In some embodiments, pattern matching can be used to determine which light emitting diodes to activate. In some embodiments, a pattern matching module is used to determine the location of the low vision configuration 3. The pattern matching module compares the calibrated and scaled sensor readings from the sensor plate 5 to several predefined patterns. The pattern matching module determines which of the predefined patterns best matches the sensor readings. The set of indicators 6 corresponding to the best matching pattern is then activated. Additional details regarding pattern matching are discussed in the prior art, such as U.S. Pat. No. 8,884,633. Such details will not be repeated here, and instead the reader is encouraged to refer directly to such details.

In some embodiments, the low vision configuration detector 1 includes a single capacitance-to-digital converter 21. In some embodiments, the sensor plates 5 can be individually connected to the capacitance-to-digital converter 21. In some embodiments, the sensor plates 5 can be individually connected to the capacitance-to-digital converter 21 via the multiplexer 18. In some embodiments, more than one sensor plate 5 can be connected to the capacitance-to-digital converter 21 at a time. In some embodiments, multiple adjacent sensor plates 5 can be electrically connected to the capacitance-to-digital converter 21. In some embodiments, multiple non-adjacent sensor plates 5 can be connected to the capacitance-to-digital converter 21. Because the sensor readings from each sensor plate 5 are equally subject to variations in the capacitance-to-digital converter 21, connecting the sensor plates 5 to a single capacitance-to-digital converter 21 using the multiplexer 18 can improve the consistency of the sensor readings of the sensor plates 5. Factors that can affect the sensor readings from the capacitance-to-digital converter 21 can include, but are not limited to, process variations, temperature variations, voltage variations, electrical noise, and aging.

In some embodiments, the sensor plate traces 35 are routed such that each of the multiple sensor plate traces 35 has substantially equal capacitance, resistance, and inductance. In some embodiments, it is desirable for each sensor plate trace 35 to have the same electrical properties so that each sensor plate 5 can respond equally to the same detectable entity.

In some embodiments, each of the sensor plate traces 35 from the capacitance-to-digital converter 21 to the respective sensor plate 5 are substantially the same length. In some embodiments, two or more of the sensor plate traces 35 from the capacitance-to-digital converter 21 to the sensor plate 5 are substantially the same length. In some embodiments, sensor plate traces 35 having substantially the same length may have more equivalent capacitance, inductance, and resistance. Sensor plate traces 35 of equal length may provide better performance by improving the uniformity of sensor readings, allowing the sensor plates 5 to respond more equally to the same detections, and providing greater immunity from environmental conditions such as temperature and humidity.

In some embodiments, each of the sensor plate traces 35, including the conductive path, has substantially the same width. In some embodiments, both the width and length of each of the sensor plate traces 35 are substantially equal. In some embodiments, the sensor plate traces 35 may have multiple portions. For example, a first portion of the trace may route the sensor plate trace 35 from the capacitance-to-digital converter 21 to a via. The via may route the sensor plate trace 35 to a different layer of the printed circuit board where a second portion of the sensor plate trace 35 may reside. In some embodiments, all of the sensor plate traces 35 may have the same length and width at each portion as the other traces in that portion. In some embodiments, two or more of the sensor plate traces 35 may have the same width throughout the first portion. In some embodiments, two or more of the sensor plate traces 35 may have the same width throughout the second portion. In some embodiments, two or more of the sensor plate traces 35 may have the same length throughout the first portion. In some embodiments, two or more of the sensor plate traces 35 may have the same length throughout the second portion.

In some embodiments, the sensor plate trace 35 may have multiple portions. In some embodiments, the sensor plate trace 35 portion may be a wire bond that resides within an integrated circuit package and routes a signal from a silicon component to a pin on the integrated circuit package. In some embodiments, the sensor plate trace 35 portion may comprise a copper layer on a first layer of a printed circuit board. In some embodiments, the sensor plate trace 35 portion may comprise a copper layer on a second layer of a printed circuit board.

In some embodiments, the capacitance-to-digital converter 21 can read out the capacitance of the sensor plate 5 and the sum of the sensor plate traces 35. In some embodiments, it may be desirable to only detect the sensor reading on the sensor plate 5 and not the sensor plate traces 35. However, because the sensor plate 5 and the sensor plate traces 35 are electrically coupled, a means to ensure a stable and uniform capacitance on the sensor plate traces 35 may be desirable. For example, it may be desirable to configure the sensor plate traces 35 such that the capacitance of the sensor plate traces 35 is uniform and stable. Thus, it may be preferable to configure the sensor plate traces 35 such that they do not change. In some embodiments, it may be preferable that the sensor plate traces 35 do not change with respect to one another, and any change in capacitance on one sensor plate trace 35 is reflected on each of the sensor plate traces 35.

In some embodiments, it may be advantageous to shield the sensor plate traces 35. Shielding the sensor plate traces 35 can protect the sensor plate traces 35 from external electromagnetic fields. Also, in some embodiments, shielding the sensor plate traces 35 can advantageously provide a more consistent environment for the sensor plate traces 35 by helping to ensure that each of the sensor plate traces 35 has an environment similar to each of the other sensor plate traces 35.

In some embodiments, each sensor plate trace 35 from the capacitance-to-digital converter 21 to each sensor plate 5 has substantially the same environment. In some embodiments, the multiple sensor plate traces 35 can be routed far enough apart to minimize capacitive and inductive coupling between the multiple sensor plate traces 35, and each sensor plate trace 35 can have a more similar environment to the other sensor plate traces 35, improving the consistency of the sensor plate traces 35. In some embodiments, one or both sides of each sensor plate trace 35 are shielded with active shielding traces.

In some embodiments, the user may be electrically coupled to the sensing circuit 27. In some embodiments, the quality of the sensor reading is improved when the conductive points of the sensing circuit 27 are coupled to the user. Electrically coupling the user to the sensing circuit 27 may provide a consistent voltage level to the sensing circuit 27, resulting in a more sensitive and higher quality sensor reading. For example, a prior art low-vision detector that drives the sensor plate 5 with 3.0V may actually only drive the sensor plate 5 with a signal that is 3.0V relative to ground. However, if the ground is floating, driving the sensor plate 5 with 3.0V may result in a 1.5V signal on the sensor plate 5 and a -1.5V signal on ground. In some embodiments, the quality of the sensor reading is not improved when the conductive points of the sensing circuit 27 are coupled to the user.

In some embodiments, electrically coupling the user to the sensing circuitry 27 may result in a higher absolute voltage amplitude on the sensor plate 5, in part because the sensing circuitry 27 may be held at a stable level. Also, in some embodiments, electrically coupling the user to the sensing circuitry 27 may result in a more consistent sensor reading.

In some embodiments, the user is electrically coupled to the ground of the sensing circuitry 27, as shown in FIG. 4. In some embodiments, the user is electrically coupled to a voltage source of the sensing circuitry 27. In some embodiments, the user is electrically coupled to different conductive points of the sensing circuitry 27.

In some embodiments, the user's hand may be electrically coupled to the sensing circuitry 27 by direct contact with the sensing circuitry 27. In some embodiments, a conductive material such as a wire may electrically couple the user's hand to the sensing circuitry 27. In some embodiments, a button that the user may need to touch to activate the low vision configuration detector 1 may include a conductive material that may be electrically coupled to the sensing circuitry 27. In some embodiments, the button may include aluminum or other conductive material such as tinned steel. In some embodiments, the aluminum button may be anodized, which may provide a pleasing cosmetic effect.

In some embodiments, the housing 19 (see FIG. 2) of the low vision configuration detector 1 may comprise a conductive material, such as conductive plastic. In some embodiments, only a portion of the housing 19 may comprise conductive plastic. The conductive housing or a portion of the conductive housing may be coupled to a conductive point of the sensing circuitry 27, thereby coupling a user to the sensing circuitry 27.

In some embodiments, carbon black can be mixed with the plastic resin to provide electrical conductivity. Many thermoplastics, including polypropylene and polyethylene, become conductive when carbon black is mixed into the plastic resin. In some embodiments, the electrical conductivity of the plastic can be advantageously controlled, with electrical conductivity increasing as the concentration of carbon black increases. In some embodiments, a plastic having a conductivity of less than 25,000 Ω-cm is sufficiently conductive to effectively couple the user to the sensing circuitry 27. In some embodiments, a high degree of electrical conductivity may be desired. In some embodiments, a lesser degree of electrical conductivity may be desired. In some embodiments, it is advantageous for the user to be coupled to the sensing circuitry by a path of less than about 50 MΩ.

In some prior art low-vision detectors, a change in the position of the user's hand can cause the sensor reading to change. This can occur in some prior art low-vision detectors because the hand forms part of the path between the sensor plate 5 and the ground. As a result, a change in the position of the hand can cause the sensor reading of the sensor plate 5 to change. This can disadvantageously reduce the accuracy of the sensor reading.

If the size and position of a user's hand could be made invariant, a calibration adjustment could be made that mathematically removed the effect of the user's hand from the raw sensor readings. However, this may not be feasible in practice. In practice, the sizes, shapes, and positions of different users' hands may be too different to make a calibration adjustment practically possible.

To improve performance in view of the above-mentioned problems, in some embodiments, a conductive handguard may be placed between the user's hand and the sensor plate 5. In some embodiments, the handguard may be grounded to the sensing circuitry 27, as shown in FIG. 4.

5 is a diagram of a controller 60 according to one embodiment. The controller 60 includes a processor 61, a clock 62, a random access memory (RAM) 64, a non-volatile memory 65, and/or other computer readable media. The non-volatile memory 65 may include a program 66 (e.g., in the form of program code or computer readable instructions for performing operations) and a calibration table 68. In operation, the controller 60 may receive the program 66 and synchronize the functions of the capacitance-to-digital converter 21 and the display circuit 25 (see FIG. 4). The non-volatile memory 65 receives and stores the program 66, a look-up table (LUT), and a calibration table 68. The program 66 may include a number of suitable algorithms, such as, for example, an initialization algorithm, a calibration algorithm, a pattern matching algorithm, a multiplexing algorithm, a display management algorithm, an active sensor activation algorithm, and an inactive sensor management algorithm.

6 is a cross-sectional view of a low-vision configuration detector including a housing, light pipes and buttons, and a printed circuit board, according to one embodiment. In an embodiment, as depicted in FIG. 6, the housing 19 includes an upper housing, an on-off switch 24, a handle 14, a plurality of light pipes 8, and a power compartment. In an embodiment, a compliant core can be configured to resiliently couple the housing 19 to the sensor board board 40. In an embodiment, the sensor board board 40 is a multi-layered printed circuit board having a top layer 44, a second layer 43, a third layer 42, and a bottom layer 41. In an embodiment, the sensor board board 40 is a multi-layered printed circuit board that couples the capacitance-to-digital converter 21, the display unit 25, and the controller 60, as described above with reference to FIG. 4. In an embodiment, the housing 19 includes plastic. In an embodiment, the housing 19 includes ABS (acrylonitrile butadiene styrene) plastic. In an embodiment, a conductive hand guard 56 shields the user's hands from the sensor board board 40. In one embodiment, the hand guard 56 is connected to the ground of the sensing circuit.

In one embodiment, the handle 14 includes a gripping surface. In one embodiment, a portion of the gripping surface includes an elastomer that makes the handle 14 easier to grip. The handle 14 is preferably positioned so as not to obscure a view of the indicator 6 when a user's hand is gripping the handle 14. In one embodiment, the power compartment includes a cavity for holding a suitable power source, such as a battery, and a battery cover for accessing the compartment.

In some embodiments, the handguard 56 may be configured such that there is no significant linear path between the sensor plate and the user's hand. In some embodiments, the housing 19 may be constructed from a conductive material that may comprise the handguard 56. In some embodiments, the conductive layer of material of the handguard 56 may be a layer of conductive plastic. In some embodiments, the conductive layer of material of the handguard 56 may be a layer of a different conductive material, such as conductive paint. In some embodiments, the conductive layer of material of the handguard 56 may be a sheet of metal hidden within the housing 19. In some embodiments, the handguard 56 may include a section of extruded aluminum that is soldered to a printed circuit board. In some embodiments, the handguard 56 may include tin-plated steel, which may provide a quick, easy, and reliable solder joint. In some embodiments, an entire layer of the printed circuit board may comprise the handguard 56 (e.g., the top layer of a printed circuit board (PCB)). In some embodiments, it may not be necessary to include an entire layer for the handguard 56, so in some embodiments, only a portion of a layer of the printed circuit board may comprise the handguard 56. For example, a ring around the outside of the printed circuit board may be the effective handguard 56.

In some embodiments, the hand guard 56 is configured to minimize the effect of hand size and position. In some embodiments, the hand guard 56 is positioned so that the hand guard 56 is close to the hand, since in some embodiments the hand guard 56 may be most effective when it is closest to the hand. In some embodiments, the hand guard 56 may be electrically coupled to the ground of the sensing circuit 27 (see FIG. 4). In some embodiments, the hand guard 56 may be coupled to the potential of the sensing circuit 27. In some embodiments, different conductive points of the sensing circuit 27 may be electrically coupled to the hand guard 56. In some embodiments, an electrical wire comprises an electrical path between the hand guard 56 and the sensing circuit 27.

In prior art hard-to-see-configuration detectors, a set of identical sensor plates 105 are typically arranged in a linear fashion, as shown, for example, in Figs. 7, 8, 9, and 10. Fig. 7 is a prior art hard-to-see-configuration detector 101 arranged on a relatively thinner surface 12. Fig. 8 is a prior art hard-to-see-configuration detector 101 arranged on a relatively thicker surface 13. Fig. 9 shows a side view of the prior art hard-to-see-configuration detector 101, illustrating the primary sensing field zones 15, 16, 17 for several sensor plates 105, including sensor plates A, B, C, D, and E. Fig. 10 shows a front view of the bottom surface of the prior art hard-to-see-configuration detector 101, illustrating the primary sensing field zones 15, 16, 17 for sensor plates A, B, C, D, and E.

Referring generally and collectively to FIGS. 7-14, each sensor plate 105 takes a sensor reading for surface 2. The sensor readings are then compared. The sensor plate 105 with the highest reading is determined to be at the location of the hard-to-see configuration. However, as depicted in FIGS. 7 and 8, sensor plates 105 near the ends of the group may not respond to hard-to-see configurations in the same way as sensor plates 105 near the center. This problem may be particularly evident when the prior art hard-to-see configuration detector 101 moves from a thinner surface to a thinner surface or less dense surface 12 to a thicker surface or more dense surface 13.

Figure 7 represents a typical sensor reading of a prior art low-vision configuration detector 101 placed on a relatively thin surface 12. The relatively thin surface 12 may be 0.375 inch thick sheet rock. Figure 8 represents a typical sensor reading of a prior art low-vision configuration detector 101 placed on a relatively thick surface 13. The relatively thick surface 13 may be 0.625 inch thick sheet rock.

In FIG. 7, the prior art hard-to-see configuration detector 101 is placed on a relatively thin surface 12. Each sensor plate 105 may have a calibration adjustment so that each has a calibrated reading (e.g., 100). If this same prior art hard-to-see configuration detector 101 were then moved to another surface 13 that is thicker or has a higher dielectric constant, the sensor reading would change. The same prior art hard-to-see configuration detector 101 on the thicker surface 13 is shown in FIG. 8. Ideally, in the absence of hard-to-see configuration, the multiple sensor plates 105 would all be on the same thicker surface 13, so that each of the sensor plates 105 on the thicker surface 13 would have a similar sensor reading to each other. However, it can be observed that the sensor readings of the sensor plates 105 near the edges produce a larger reading than the sensor plates 105 near the center. In FIG. 8, it can be seen that the sensor plate 105 near the center has a sensor reading of 200, while the sensor plate 105 at the end has a sensor reading of 250.

In the prior art hard-to-see configuration detector 101 of FIG. 8 and other prior art hard-to-see configuration detectors, the sensor plates 105 present at the edge are isolated as they generate an electric field 9 that extends above the edge of the group of sensor plates 105. As a result, the sensor plates 105 near the edge may respond with disproportionately higher readings when placed on a thicker surface 13. The controller 60 may have adversely difficulty determining whether the elevated sensor reading is due to the presence of a hard-to-see configuration or due to the prior art hard-to-see configuration detector 101 being placed on a thicker surface 13. The disclosed embodiments may address these and other challenges.

Figure 9 shows field lines for the prior art low vision configuration detector 101 of Figures 7 and 8. Figure 9 shows a group of sensor plates 105 and a two-dimensional representation of the field lines for each sensor plate 105. The field lines are shown for illustrative purposes and are representative of the actual sensing field. The field lines depicted are equipotential electric field lines. However, this diagram does not limit the scope of the present disclosure to only this type of field. Vector electric field lines or magnetic field lines can be depicted and are within the scope of the present disclosure. The sensing field can be an electromagnetic field, which is an electric field, a magnetic field, or a combination of electric and magnetic fields.

In FIG. 9, there are thirteen sensor plates 105. While all of the sensor plates 105 can be driven simultaneously by the same signal, one sensor plate 105 is sensed at a time. Because the sensor plates 105 are driven simultaneously by the same signal, the sensing field is defined by the fields produced by the group of sensor plates 105 as shown in FIG. 9. Active shielding planes are not shown, but in some embodiments active shielding may contribute to the sensing field. Five of the sensor plates 105 are labeled A, B, C, D, and E. The field lines emanating from sensor plate E are essentially parallel to sensor plate E. However, the field lines emanating from sensor plate A are not quite parallel to sensor plate A. These field lines are not similar in direction and intensity at each point within the primary sensing field zone, so sensor plates A and E do not have similar sensing fields within these primary sensing field zones.

In contrast, sensor plate D and sensor plate E have similar primary sensing field zones because the volumes of the sensing fields that sensor plate D and sensor plate E can effectively sense and the sensing fields within the primary sensing field zones are similar. The sensing fields within the primary sensing field zones are similar when the direction of the sensing field and the intensity of the sensing field are similar at each point within the primary sensing field zone.

Figure 10 shows the same concept from a different angle or perspective. In Figure 10, the five sensor plates 105 are again referred to as A, B, C, D, and E. The approximate primary sensing field zones for each of the sensor plates 105 are highlighted. On the two-dimensional view of Figure 10, the primary sensing field zone 15 for sensor plate A is shown by a drawing of the sensing field lines for sensor plate A. On the two-dimensional view of Figure 10, the primary sensing field zone 16 for sensor plate B is shown by a drawing of the sensing field lines for sensor plate B. On the two-dimensional view of Figure 10, the primary sensing field zone 17 for sensor plate C is shown by a drawing of the sensing field lines for sensor plate C.

9 and 10 show the primary sensing field zones in a two-dimensional view. However, in reality, there may be three-dimensional primary sensing field zones. For each sensor plate 105, there may be a three-dimensional zone that includes the primary sensing field zone for each given sensor plate 105. In contrast to the prior art embodiment of FIGS. 9 and 10, in certain embodiments of the present disclosure, the sensor plates 105 may have equivalent primary sensing field zones. Each sensor plate 105 of a group with equivalent primary sensing field zones responds equally to changes in surface. The present disclosure shows several configurations in which each sensor plate 105 of a group may have equivalent primary sensing field zones. In certain embodiments, each sensor plate 105 with similar primary sensing field zones may have similar changes in sensor readings in response to changes in the surface being detected.

11 is a flow diagram of a method 200 for detecting poor vision configurations behind a surface according to one embodiment. As shown in the flow diagram of FIG. 11, a first operation can be initialization of the detector (202), which can involve running an initialization algorithm. The detector can follow one embodiment described herein. After initialization, the sensor plates can be read (204). In one embodiment, each sensor plate can be read multiple times, each time using a different configuration. The different configurations can include different drive currents, different voltage levels, different sensing thresholds, or other different configuration parameters. Each of these readings of the sensor plate can be referred to as a native read. In one embodiment, multiple native readings are added together to generate a reading. In one embodiment, there can be a separate reading for each sensor plate.

In one embodiment, each of these readings undergoes a calibration adjustment (206), which is accomplished by adding a predetermined calibration value to each reading. In one embodiment, after calibration, the readings for each of the sensor plates can be equal if the detectors are placed on a uniform surface.

In one embodiment, the highest sensor plate reading is compared (208) against the lowest sensor plate reading. This difference is then compared (208) to a threshold. In one embodiment, if the difference is less than a predetermined threshold, all indicators may be turned off (210) to indicate that no stud is present. If the difference is greater than a predetermined threshold, a determination may be made as to which indicators to activate. In certain embodiments, the readings may be scaled (212) to a predetermined range, which may involve setting the lowest value to a number such as 0 and scaling the highest reading to a value such as 100. All intermediate values may then be scaled proportionally. The scaled reading may then be compared (214) against a predetermined pattern that is similarly scaled.

In some embodiments, there may be a set of predefined patterns. The set of predefined patterns may correspond to various combinations of hidden configurations that the detector may encounter. For example, the set of predefined patterns may correspond to various locations for a single stud. In some embodiments, the set of predefined patterns may include combinations of locations for two studs. A pattern matching algorithm may be used to determine which of the predefined patterns best matches the reading pattern. The detector may then activate an indicator that corresponds to the best matching predefined pattern (216).

In another embodiment, after calibrating the sensor plate readings, it is determined whether a hard-to-see configuration is present. The lowest sensor plate reading can be subtracted from the highest sensor plate reading. If this difference is greater than a threshold, it is determined that a hard-to-see configuration is present. If it is determined that a hard-to-see configuration is not present, all indicators can be deactivated. If a hard-to-see configuration is present, the process can begin to determine the location and width of the hard-to-see configuration. In one embodiment, all current sensor plate readings can be scaled, with the lowest reading scaled to a predetermined value (e.g., 0) and the highest reading scaled to a second predetermined value (e.g., 100). All intermediate values can be scaled proportionally. The scaled readings can be more easily compared against a set of predefined patterns.

Figure 12 is a currently available low-vision configuration detector 1200 with a group of sensor plates arranged in a typical plate configuration. As shown, the low-vision configuration detector 1200 may include three or more sensor plates 1205, a common plate 1202, and an active shielding plate 1223.

The sensor plates 1205 of the low vision configuration detector 1200 are linearly arranged to form a sensor array 1207. As shown, the sensor plates 1205 can have the same geometric shape and can be equally spaced apart. Each sensor plate 1205 has an inner boundary that extends along at least a portion of the inner boundary of one or more of the other sensor plates 1205 and an outer boundary that is disposed at the outer boundary of the sensor array 1207. The linear sensor array includes two end sensor plates 1210, 1212 and at least one non-end sensor plate 1214.

Each sensor plate 1205 is configured to obtain a sensor reading that varies based on the proximity of the sensor plate 1205 to one or more surrounding objects and the material properties of each of the one or more surrounding objects. To facilitate the sensor reading, a region of each sensor plate 1205 can form a first end of a corresponding electric field.

The common plate 1202 can form a second end of the corresponding electric field of each sensor plate 1205. The common plate 1202 has a length 1220 that extends along the length 1222 of the sensor array, with the common plate 1202 extending along one outer boundary of each sensor plate 1205. As shown, the common plate 1202 extends above the entire length dimension of the sensor array 1207. Common plates in currently available plate configurations are at least 17 millimeters longer than the sensor array, whether due to the size or shape of the housing, the shielding configuration, or other reasons. The electric field of the end sensor plate formed with such a longer common plate is not uniform compared to the electric field formed with the non-end sensor plate formed with such a longer common plate.

13 is a bottom front view of a hard-to-see configuration detector 1300 having a sensor plate cluster 1301 arranged in an improved plate configuration including a shortened common plate 1302. As shown, the hard-to-see configuration detector 1300 may include three or more sensor plates 1305, a shortened common plate 1302, and an active shield plate 1323.

In the illustrated embodiment, the sensor plates 1305 are linearly arranged to form a sensor array 1307. As shown, the sensor plates 1305 may have the same geometric shape and may be equally spaced apart. In other embodiments, the sensor plates 1305 may vary in size and/or shape and may be spaced apart differently based on the position of the sensor plates 1305 in the sensor array 1307. The linear sensor array 1307 includes two end sensor plates 1312, 1312 and at least one non-end sensor plate 1314.

Each sensor plate 1305 is configured to obtain a sensor reading that varies based on the proximity of the sensor plate 1305 to one or more surrounding objects and the material properties of each of the one or more surrounding objects. To facilitate the sensor reading, a region of each sensor plate 1305 can form a first end of a corresponding electric field.

The shortened common plate 1302 can form a second end of the corresponding electric field of each sensor plate. The shortened common plate 1302 has a length 1320 that extends along the length 1322 of the sensor array 1307, where the common plate 1302 extends along the sensor array 1307. In some embodiments, the shortened common plate 1302 may not extend along one or both of the end sensor plates 1302, 1312. In some embodiments, the length 1320 of the shortened common plate 1302 is less than the length of the sensor plate cluster 1301. In some embodiments, the sensor plate cluster 1301 includes a sensor plate 1305. In some embodiments, the sensor plate cluster 1301 includes a sensor plate 1305 and an active shield plate 1323. In some embodiments, the sensor plate cluster 1301 also includes a common plate 1302 and may also include circuitry mounted on a side of the sensor plate cluster 1301 opposite the sensor plate 1305. In one embodiment, the length 1320 of the shortened common plate 1302 is less than the length of the sensor plate array 1307 .
In some embodiments, the length 1320 of the shortened common plate 1302 is less than the length of the sensor plate cluster 1301. In some embodiments, the length of the common plate is less than the overall length of the sensor plate 1305 and the active shield plate 1323. In the illustrated embodiment, the shortened common plate 1302 is centered along the sensor array 1307. In some embodiments, the shortened common plate 1302 can be off-center.

The active shielding plate 1323 is disposed between the sensor plate 1305 and the shortened common plate 1302 to separate the sensor plate 1305 and the shortened common plate 1302. In the illustrated embodiment, the active shielding plate 1323 surrounds the shortened common plate 1303 along three sides of the shortened common plate 1303. In other embodiments, the active shielding plate 1323 may only extend along the length 1320 of the shortened common plate 1302. However, having the active shielding plate 1323 surround the common plate may reduce manufacturing complexity.

In some embodiments, one sensor plate 1305 can be sensed at a time. In some embodiments, when sensing one sensor plate 1305, all sensor plates 1305, including the active shield plate 1323, are driven with the same signal as the sensor plate 1305 being sensed. When the sensor array 1307 plus the active shield plate 1323 are driven together, the field lines of the corresponding electric field can be pushed deeper into the plane being sensed than would be possible if only a single sensor plate 1305 were driven. In some embodiments, this allows the field lines from a single sensor plate 1305 to penetrate deeper and sense the single sensor plate 1305 deeper than if the single sensor plate 1305 were driven alone.

Figure 14 shows the electric fields generated by the plate configuration of the prior art low vision configuration detector 1200 of Figure 12. Each sensor plate 1205 is configured to provide a primary coupling area 1402, 1412 to form a first end of a corresponding electric field 1406, 1408. Additionally, the common plate 1202 is configured to provide a corresponding primary coupling area 1404, 1414 to correspond to the sensor plate 1205 and form a second end of the corresponding electric field 1406, 1408 of the sensor plate 1205.

The primary bonding regions 1402, 1412 are the regions of the sensor plate 1205 where the electric fields 1406, 1408 primarily couple. In the prior art shown, the primary bonding region 1402 of the edge sensor plate 1210 lies on a line 1420 with the corresponding primary bonding region 1404 of the common plate 1202. Similarly, the primary bonding region 1404 of the non-edge sensor plate 1214 lies on a line 1422 with the corresponding primary bonding region 1414 of the common plate 1202. As shown, the line 1420 of the primary bonding region 1402 of the edge sensor plate 1210 to the corresponding primary bonding region 1404 of the common plate 1202 is approximately parallel to the line 1422 of the corresponding primary bonding region 1404 of the non-edge sensor plate 1214 to the corresponding primary bonding region 1414 of the common plate 1202.

As shown, in this configuration, the electric field 1406 generated from the edge sensor plate 1210 has a different geometry than the electric field 1408 generated from the non-edge sensor plate 1214. The electric fields generated by the surrounding sensor plates 1205 affect each of the other sensor plates 1205. A non-uniform electric field 1406 results from the edge sensor plate 1210 that does not have sensor plates 1205 along both sides. The non-uniformity of the electric field 1406 may result in inaccurate detection or missed detection of the hard-to-see configuration. For example, the electric field 1406 generated by the edge sensor plate 1210 may penetrate a larger surface than the electric field 1408 generated by the non-edge sensor plate 1214. Due to the difference in sensing area, the edge sensor plate 1210 may erroneously identify the hard-to-see configuration.

15 shows electric fields 1506, 1508 generated between the edge sensor plate 1310 and the non-edge sensor plate 1314 in the plate configuration of the low vision configuration detector 1300 of FIG. 13. Primary coupling areas (e.g., 1502, 1512) can couple the sensor plate 1305 to the shortened common plate 1302. Each sensor plate 1305 is configured to provide a primary coupling area (e.g., 1502, 1512) to form a first end of a corresponding electric field. The shortened common plate 1302 is configured to provide corresponding primary coupling areas (e.g., 1504, 1514) respectively corresponding to the sensor plate 1305 to form a second end of the corresponding electric field of the sensor plate 1305.

For example, as shown, the end sensor plate 1310 is configured to provide a primary bond area 1502 and the non-end sensor plate 1314 is configured to provide a primary bond area 1512. The common plate 1302 is configured to provide a corresponding primary bond area 1504 that corresponds to the primary bond area 1502 of the end sensor plate 1310 and a corresponding primary bond area 1514 that corresponds to the primary bond area 1512 of the non-end sensor plate 1314.

As shown, the electric fields 1506, 1508 couple the primary bonding regions 1502, 1512 of the sensor plate 1305 to the corresponding primary bonding regions 1504, 1524 of the common plate 1302. The primary bonding region 1502 of the edge sensor plate 1310 is on a first line 1520 with the corresponding primary bonding region 1504 of the common plate 1302. Additionally, the primary bonding region 1512 of the non-edge sensor plate 1314 is on a line 1522 with the corresponding primary bonding region 1514 of the common plate 1302.

To achieve similar electric fields, the first line 1520 and the second line 1522 are not parallel between the coupling regions of the sensor plate 1305 and the common plate 1302. The electric field generated by the adjacent sensor plate 1305 affects each of the other sensor plates 1305. Because the edge sensor plate 1310 has only one adjacent sensor plate 1305, the electric field 1506 will naturally travel a longer distance than the electric field 1508 of the non-edge sensor plate 1324. As shown in FIG. 14, the longer path may extend beyond the low-vision configuration detector. In contrast, as shown in FIG. 15, the shortened common plate 1302 draws the electric field 1506 to a position near the electric field 1508. This may be because the sizing and placement of the shortened common plate 1302 makes the electric field 1506 from the end sensor plate 1310 more similar to the electric field 1508 from the non-end sensor plate 1314 as compared to the prior art low-vision configuration detector.

In some embodiments, the electric field 1506 corresponding to the end sensor plates 1310 has a similar size, shape, direction, and/or geometry as the electric field 1508 corresponding to the non-end sensor plates 1314. In some embodiments, the electric field corresponding to each sensor plate 1305 has the same size, shape, direction, and/or geometry as each other sensor plate 1305. In some embodiments, the electric fields corresponding to each group of sensor plates 1305 have the same size, shape, direction, and/or geometry.

In some embodiments, similar electric field size, shape, direction, and/or geometry results in more consistent readings because each sensor plate 1305 can respond more uniformly to changes to the surface or object being detected. Sensor plates 1305 that respond similarly can better detect difficult-to-see features that are deeper in a wall or that may be more difficult to detect. Similar electric fields can result in a difficult-to-see feature detector that can be used on a variety of different surfaces and that works equally well on a variety of different surfaces. Also, a difficult-to-see feature detector that can sense deeper or more accurately, or both.

In some embodiments, the low-vision configuration detector may have a common plate that is less than the overall length dimension of the three or more sensor plates. This configuration may result in an electric field having a similar size, shape, and/or geometry. In some embodiments, the low-vision configuration detector may have a common plate that is less than the overall length dimension of the three or more sensor plates plus 16 millimeters. This configuration of a common plate that is less than the length of the sensor array plus 16 millimeters may result in an electric field having a similar size, shape, direction, and/or geometry. In other words, in some embodiments, there may be a length that is defined as the length added to the array. The length added to the array may be up to 16 millimeters longer than the overall length of the sensor array. In some embodiments, the length added to the array may be up to 1.5 times the sensor width longer than the overall length of the sensor array. In other words, the length dimension of the common plate may be up to 1.5 times the width of the sensor plate (e.g., the width of the end sensor plate) longer than the array. A low-vision configuration detector having a common plate that is less than the length added to the array may be referred to as a shortened common plate. In some embodiments, a low-vision configuration detector with a shortened common plate may have multiple fields each having a more similar size, shape, orientation, and/or geometry.

As a result of the increased similarity of the electric fields, the low-vision detector can sense more accurately and deeper within and/or through the plane.

A hard-to-see-configuration detector with a shortened common plate may have multiple electric fields each having a more similar size, shape, orientation, and/or geometry compared to a hard-to-see-configuration detector with a common plate described in the prior art. A more uniform size, shape, orientation, or geometry of the electric field associated with each sensor plate may provide a more uniform reading for each sensor plate. Multiple sensor plates each having similar electric fields may each respond more uniformly to different surface materials and thicknesses. For example, an embodiment of a hard-to-see-configuration detector with a shortened common plate may be placed on a particular surface, such as a surface of 0.25 inch thick sheet rock. Each sensor plate may have the same reading (e.g., a reading of 100 units) when placed on this surface. In this example, if the same hard-to-see-configuration detector is placed on a different surface (e.g., 0.50 inch thick sheet rock), the readings may change to different values, but again the readings (e.g., a value of 200 units) of each sensor plate may be similar. When the readings from each sensor plate provide similar readings, regardless of what surface the hard-to-see configuration detector is located on, any variation in the sensor plate readings can be attributed to the presence of the hard-to-see configuration. The hard-to-see configuration detector with the shortened common plate can maintain a higher uniformity of readings across various planes than the hard-to-see configuration detector of the prior art. The uniformity of readings regardless of surface allows for more accurate and deeper sensing, more accurate discrimination of configurations, and more accurate simultaneous sensing of two objects. In some embodiments, the shortened common plate can have the advantageous effect of more accurately positioning the sensing field for each sensor plate in the vicinity of the sensor plate. As a result, the hard-to-see configuration detector can sense more accurately and deeper.

In currently available low-vision configuration detectors, the width of the common plate is less than 8.00 millimeters. In some embodiments of improved low-vision configuration detectors, performance may be improved when the width of the common plate is greater than 8.00 millimeters. A low-vision configuration detector with a common plate greater than 8.00 millimeters wide may have multiple electric fields each having a more similar size, shape, orientation and/or geometry compared to low-vision configuration detectors with a common plate described in the prior art.

15, the hard-to-see configuration detector 1300 may have the primary bonding areas 1502 of the edge sensor plates 1310 of the sensor array 1307 on a first line 1520 with corresponding primary bonding areas 1504 of one or more common plates. The hard-to-see configuration detector 1300 may also have the primary bonding areas 1512 of the non-edge sensor plates 1314 of the sensor array 1307 on a second line 1522 with corresponding primary bonding areas 1514 of one or more common plates. In some embodiments, the first line 1520 and the second line 1522 are not parallel. This may result in electric fields having more similar sizes, shapes, and geometries.

In other words, if the electric field corresponding to the non-end sensor plate 1314 begins and ends on the first line 1520, if the electric field corresponding to the end sensor plate 1310 begins and ends on the second line 1522, and if the first and second lines are not parallel, the electric field 1506 corresponding to the end sensor plate 1310 may be more similar to the electric field 1508 corresponding to the non-end sensor plate 1314 than if the first and second lines 1520, 1522 were parallel. As a result, each sensor plate 1305 may respond more uniformly to changes in the surface or object being detected. As a result, the low-vision configuration detector 1300 may sense more accurately and more deeply.

For example, if the presence of a hard-to-see feature causes one of the sensor plates 1305 to have a particular reading when an object is located near the sensor plates 1305, it would be desirable to have the same reading for each sensor plate 1305 when the hard-to-see feature is located in the same position relative to the sensor plates 1305. The uniform response just described may allow for more independent sensing of the surface material or thickness. As a result, studs are more accurately sensed independent of the surface material or thickness.

The plate configuration of the embodiment of the hard-to-see-configuration detector 1300 of FIG. 15 causes the electric fields 1506 formed from the edge sensor plates 1310 and the electric fields 1508 formed from the non-edge sensor plates 1314 to have a similar size, shape, or orientation. This is in contrast to the electric fields depicted in FIG. 14. The uniformity of the electric fields may improve the accuracy of the hard-to-see-configuration detector. The improved accuracy may result in the electric fields of each sensor plate 1305 having similar readings (readings that span similar depths and widths).

16 illustrates the electric fields 1606, 1608 emanating from the edge sensor plate 1310 and the non-edge sensor plate 1314 for a plate configuration of a low-vision configuration detector 1600 having multiple common plates 1601. As shown, the multiple common plates 1601 can be sized, configured, and aligned such that the electric field 1606 formed from the edge sensor plate 1310 has a similar size, shape, and/or orientation as the electric field 1608 formed from the non-edge sensor plate 1314. The multiple sensor plates 1601 can be arranged linearly to extend along the length of the sensor array 1307.

15, the primary bonding areas 1602 of the edge sensor plates 1310 of the sensor array 1307 lie on a first line 1620 with the corresponding primary bonding areas 1604 of the multiple common plates 1601. Additionally, the primary bonding areas 1612 of the non-edge sensor plates 1314 of the sensor array 1307 lie on a second line 1622 with the corresponding primary bonding areas 1614 of the multiple common plates 1601. Due to the positioning of the multiple common plates 1601, the first line 1620 and the second line 1622 are not parallel, causing the electric field 1606 formed from the edge sensor plates 1310 to have a similar geometric shape to the electric field 1608 formed from the non-edge sensor plates 1314. The uniformity of the electric fields 1606, 1608 can improve the accuracy of the low vision configuration detector 1600. Each of the multiple common plates 1601 can be activated independently. In some embodiments, the multiple common plates 1601 can be activated by coupling them to a fixed voltage level, such as 0 volts or 3 volts, or any other fixed voltage level. In some embodiments, the multiple common plates 1601 can be activated by driving them with an AC voltage.

FIG. 17 is a flow chart illustrating a method 1700 for detecting a hard-to-see configuration behind a surface. The method may include step 1702 of taking sensor readings between three or more sensor plates of a hard-to-see configuration detector and a shortened common plate. The three or more sensor plates may be linearly arranged in a sensor array. The sensor readings may comprise a range of sensing fields formed between the three or more sensor plates of the hard-to-see configuration detector and the common plate. The dimensions of the common plate may be less than the dimensions of the sensor array.

The method further includes measuring 1704 sensor readings of the three or more sensor plates with a sensing circuit and comparing 1706 the measured sensor readings of different regions of the sensing field. The measured sensor readings may be capacitance or electromagnetic readings. Additionally, the method may toggle 1708 an indicator from an inactive state to an active state to indicate the location of an area of the sensing field having a relatively high sensor reading.

18 illustrates a low-vision configuration detector 1800 having an alternative configuration of multiple sensor plates 1805 according to another embodiment of the present disclosure. The low-vision configuration detector 1800 includes end sensor plates 1874 that are smaller in area than the non-end sensor plates in the sensor array 1807. In this embodiment, the end sensor plates 1874 are narrower than the non-end sensor plates 1875 of the sensor array 1807. Each sensor plate 1805 of the sensor array 1807 is configured to be electrically coupled to the common plate 1876 by electric fields 1881, 1882. Each sensor plate 1805 of the sensor array 1807 is configured to provide a primary coupling region 1879, 1880 that can form a first end of the electric fields 1881, 1882. Additionally, the common plate 1876 is configured to provide corresponding primary coupling regions 1885, 1886 to correspond to the edge sensor plate 1874 and the non-edge sensor plate 1875, respectively, forming second ends of the corresponding electric fields 1881, 1882 of each sensor plate 1805.

The primary bond area 1879 of the end sensor plate 1874 lies on a first line 1883 that extends from the primary bond area 1879 of the end sensor plate 1874 to the primary bond area 1885 of the common plate 1876. The primary bond area 1880 of the non-end sensor plate 1875 lies on a second line 1884 that extends from the primary bond area 1880 of the non-end sensor plate 1875 to the primary bond area 1886 of the common plate 1876.

In the configuration of FIG. 18, the common plate 1876 has a length 1878 that is longer than the length 1888 of the sensor array 1807. In some embodiments, the length 1878 of the common plate 1876 can be equal to (or closely similar to) the length of the shielding plate 1877, which is disposed between the common plate 1876 and the sensor array 1807. Each of the non-end sensor plates 1875 has a length 1873 and a width 1871 that are the same as (or closely similar to) the length and width of the other non-end sensor plates 1875 of the sensor array 1807. The end sensor plates 1874 have a length 1872 that is equal to (or closely similar to) the length 1873 of the non-end sensor plates 1875, but a width 1870 that is smaller than the width 1871 of the non-end sensor plates 1875.

It can be seen that the total area of the end sensor plate 1874 is smaller than the total area of the non-end sensor plate 1875. The smaller sensor area allows the end sensor plate to be less responsive to changes in surface 2, and the response of the end sensor plate more closely matches the response of the non-end sensor plate. In some prior art difficult-to-see configuration detectors, the end sensor plate and the non-end sensor plate respond differently to a changing surface 2 or a changing difficult-to-see configuration 3, respectively. This response issue is discussed in the dialogue surrounding Figures 7 and 8. The end sensor plate 1879 can have a smaller area and be less responsive to different surfaces and different difficult-to-see configurations, so that the end sensor plate 1879 responds more similarly to the non-end sensor plate 1875. Furthermore, the electric field 1881 formed between the end sensor plate 1874 and the common plate 1876 will be smaller than when the width 1870 of the end sensor plate 1874 is the same (or closely similar) to the width 1871 of the non-end sensor plate 1875. In other words, the narrower width 1870 of the end sensor plate 1874 results in a smaller electric field 1881, and the shape of the electric field 1881 is more similar to the shape of the electric field 1882 between the non-end sensor plate 1875 and the common plate 1876 (including a more similar detection depth into the plane). In contrast to the electric field 1406 coupling the wide end sensor plate 1210 to the common plate 1202 of FIG. 14, the electric field 1881 between the coupling regions 1879, 1880 of the narrower end sensor plate 1874 and common plate 1876 of FIG. 18 does not diverge as sharply as an end sensor plate having the same width as the non-end sensor plate 1875. The electric field 1881 between the end sensor plate 1874 and the common plate 1876 is more similar to the electric field between the non-end sensor plate 1875 and the common plate 1876. As described above, the more similar the shapes of the electric fields 1881 and 1882 are, the more predictably the sensor plate readings change, thereby more accurately detecting the difficult-to-see configuration.

In some embodiments according to the configuration shown in FIG. 18, when the size, shape, direction and/or geometry of the electric fields 1881, 1882 between the sensor plates 1874, 1875 of the sensor array 1807 is relatively small, the sensor plates 1874, 1875 can respond similarly to obstacles in the path of the electric fields 1881, 1882 of the sensor plates 1874, 1875. In other words, the greater uniformity of the edge electric field 1881 and the non-edge electric field 1882 allows each of the sensor plates 1805 to respond more uniformly to changes in the surface or object being detected, allowing for more consistent readings. Sensor plates 1805 that respond similarly can better detect difficult-to-see structures that are deeper in the wall or that may be more difficult to detect. Similar electric fields 1881, 1882 can result in a difficult-to-see structure detector that can be used on a variety of different surfaces and that can work equally well on each of the various different surfaces. A low-vision configuration detector 1800 with uniform edge and non-edge fields 1881 and 1882 can sense deeper, or more accurately, or deeper and more accurately.

19 is similar to FIG. 18 and illustrates a hard-to-see configuration detector 1900 having an alternative edge sensor plate configuration in accordance with another embodiment of the present disclosure. The edge sensor plate 1981 has a different shape than the other sensor plates. In the hard-to-see configuration detector 1900 of FIG. 19, the edge sensor plate 1981 has a trapezoidal shape. In one embodiment, the shape of the edge sensor plate 1981 is different from the shape of the other sensor plates, allowing the edge sensor plate 1981 to detect hard-to-see configurations more similarly to non-edge sensor plates.

The end sensor plate 1981 may have the same length 1985 as the non-end sensor plate 1982, but the bottom width 1984 is wider than the top width 1988. In some embodiments, the bottom width 1984 of the end sensor plate 1981 may be equal to the bottom width 1986 of the non-end sensor plate 1982, and the top width 1988 of the end sensor plate 1981 may be smaller. In some embodiments, the bottom width 1984 of the end sensor plate 1981 may be wider than the width 1986 of the non-end sensor plate 1982, and the top width 1988 of the end sensor plate 1981 may be equal to the width 1986 of the non-end sensor plate 1982. In some embodiments, both the top width 1988 and the bottom width 1984 may be wider than the width 1986 of the non-end sensor plate 1982, and the bottom width 1984 of the end sensor plate 1981 is greater than the top width 1988 of the end sensor plate 1981. In some embodiments, both the top width 1988 and the bottom width 1984 can be narrower than the width 1986 of the non-end sensor plate 1982, and the bottom width 1984 of the end sensor plate 1981 is wider than the top width 1988 of the end sensor plate 1981.

FIG. 20 shows a hard-to-see-configuration detector 2001 positioned on a portion of sheet rock 2002 (or a similar surface) to detect hard-to-see-configuration 2003, according to one embodiment. FIG. 21 is a perspective view of the hard-to-see-configuration detector 2001 of FIG. 20. FIG. 22 shows the sensor side of the hard-to-see-configuration detector 2001, which includes multiple sensor plates 2205.

Referring to Figures 20-22, generally and generally, the low vision configuration detector 2001 includes three or more sensor plates 2205, sensing circuitry (see Figure 23), one or more indicators 2006, one or more proximity indicators 2039, a handle 2014, an active shield plate 2623 (see Figure 26), and a housing 2019 that provides or houses a battery cover 2028.

Each of the three or more sensor plates 2205 can obtain a sensor reading that varies based on the proximity of the sensor plate 2205 to one or more surrounding objects and the material properties of each of the one or more surrounding objects. The three or more sensor plates 2205 collectively produce a sensing field. Each individual sensor plate 2205 of the three or more sensor plates 2205 produces a corresponding primary sensing field zone, which may be a three-dimensional geometric volume within the sensing field in which the individual sensor plate 2205 contributes more strongly to the sensing field than any other of the three or more sensor plates 2205. All of the three or more sensor plates 2205 produce geometrically similar primary sensing field zones. A sensing circuit is coupled to the three or more sensor plates 2205 to measure the sensor readings of the three or more sensor plates 2205.

In some embodiments, each sensor plate 2205 can be part of a group 2207 of sensor plates 2205. Each group 2207 can include more than one sensor plate 2205 and can also include an active shield plate 2623. The sensor plate 2205 and the active shield plate 2623 can be on different planes. Nevertheless, if the sensor plate 2205 and the active shield plate 2623 are driven simultaneously, in some embodiments, the sensor plate 2205 and the active shield plate 2623 can be part of the same group 2207 of sensor plates 2205. Each sensor plate 2205 has a geometric shape defined by its shape. Each sensor plate 2205 also has a perimeter. In some embodiments, the perimeter can be made up of multiple parts. In some embodiments, each part of the perimeter is an inner boundary 2210 or an outer boundary 2211. In some embodiments, if the sensor plate 2205 has a portion of its border that is adjacent to the border of the group 2207, that portion comprises the outer boundary 2211. In some embodiments, if the sensor plate 2205 has a portion of its border that is not adjacent to the border of the group 2207, that portion comprises the inner boundary 2210.

In an embodiment for sensing the position of the hard-to-see feature 2003, a current source can be used to drive the sensor plate 2205 and the hard-to-see feature detector 2001 measures the time it takes for the sensor plate 2205 to reach a threshold voltage, thereby obtaining a sensor reading. In another embodiment, a charge share mechanism is used to obtain a sensor reading. In another embodiment, a radio frequency signal is placed on the sensor plate 2205 to obtain a sensor reading. In each of these embodiments, a signal is driven and sensed on the sensor plate 2205.

In some embodiments, only one sensor plate 2205 can be actuated at a time. In these embodiments, a single sensor plate 2205 can be isolated when producing a sensing field.

In some embodiments, the group 2207 of sensor plates 2205 are all driven simultaneously with the same signal. In these embodiments, the group 2207 of sensor plates 2205 can generate a sensing field. In some embodiments, multiple sensor plates 2205 can each be driven simultaneously with the same signal, or only a single sensor plate 2205 can be sensed. Advantageously, driving multiple sensor plates 2205 simultaneously can generate field lines that go deeper into the poor vision configuration than driving only a single sensor plate 2205. Deeper field lines allow for deeper sensing. In some embodiments, the group 2207 of sensor plates 2205 and the active shield plate 2623 can all be driven simultaneously with the same signal and can generate a sensing field together.

Each sensor plate 2205 has a primary sensing field zone. In some embodiments, the primary sensing field zone is a three-dimensional geometric volume of the sensing field and associated field lines to which an individual sensor plate 2205 is more sensitive than the active shield plate 2623 (if present) or any other sensor plate 2205. In some embodiments, it is desirable for each sensor plate 2205 to have similar primary sensing field zones. In some embodiments, it is desirable for each sensor plate 2205 to have geometrically similar primary sensing field zones and similar sensing fields within each primary sensing field zone.

Figure 22 shows a group 2207 of eight sensor plates 2205. Each of the eight sensor plates 2205 is triangular in shape. Each triangular sensor plate 2205 has two portions, each having an inner boundary 2210. Each sensor plate 2205 also has one portion, having an outer boundary 2211.

In one embodiment, as depicted in FIG. 22, the group 2207 may include eight triangular sensor plates 2205, each having a similar geometric shape. The group 2207 of sensor plates 2205 may be arranged in a square-shaped area, with each side of the square-shaped area measuring approximately 3 inches (76.2 millimeters). In one embodiment, each of the sensor plates 2205 may be in the shape of an isosceles triangle. In one embodiment, as depicted in FIG. 22, the sensor plates 2205 may be arranged such that the hypotenuses of two triangular sensor plates 2205 are adjacent to each other. In one embodiment, two sensor plates 2205 with adjacent hypotenuses may approximate a square and fit within one quadrant of the group 2207 of sensor plates 2205. In one embodiment, there may be two such triangles positioned in each quadrant, with the entire group 2207 including eight sensor plates 2205, as depicted in FIG. 22. In some embodiments, the distance between adjacent sensor plates 2205 can be approximately 2.0 millimeters.

In FIG. 22, the eight sensor plates 2205 can collectively produce a sensing field. In some embodiments, the active shield plate 2623 can contribute to the sensing field. In the embodiment of FIG. 22, each sensor plate 2205 can have a similar primary sensing field zone. In this embodiment, the radial symmetry of the sensor plates 2205 can provide each sensor plate 2205 with a geometrically similar primary sensing zone. Similarly, each sensor plate 2205 can also have a similar sensing field within each primary sensing field zone. As a result, the low-vision configuration detector 2001 assembled with the configuration of FIG. 22 can provide improved performance. When the low-vision configuration detector 2001 moves from a thin surface to a thicker surface, the sensor readings for each of the sensor plates 2205 can have a similar increase in value.

In some embodiments, a sawtooth edge or border can have the same effective edge as a straight edge without a sawtooth shape. In some embodiments, an edge with a very thin curve can have the same effective edge as a straight edge without a thin curve. In some embodiments, a sensor plate 2205 with a slot therein has the same effective geometry as an equivalent sensor plate 2205 that differs in not having a slot. In some embodiments, a sensor plate 2205 with a small hole therein can have the same effective geometry as an equivalent sensor plate 2205 that does not have a hole. Many other geometries are possible that may be effectively equivalent to other substantially equivalent geometries. Many other edges are possible that may be effectively equivalent to other substantially equivalent edges. If a geometry or edge has substantially equivalent properties to another geometry or edge, the two may be considered similar.

In one embodiment, the group 2207 of sensor plates 2205 is configured such that each sensor plate 2205 in the group 2207 has the same geometric shape. In one embodiment, each of the sensor plates 2205 in the group 2207 is radially symmetric.

The multiple indicators 2006 can be toggled between an inactive and an active state to indicate the location within the sensing field of areas of relatively high sensor readings. An activated indicator 2004 can indicate the location of the hard-to-see configuration 2003. A proximity indicator 2039 can indicate that the hard-to-see configuration detector 2001 may be near the hard-to-see configuration 2003.

20-22, the indicators 2006 are positioned on a layer above the sensor plates 2205. In some embodiments, there may be an active shield plate 2623 between the sensor plates 2205 and the indicators 2006 so that the indicators 2006 do not interfere with the function of the sensor plates 2205. In some embodiments, it may be desirable to position the indicators 2006 on a layer above the sensor plates 2205 so that each of the sensor plates 2205 may have a distance similar to the distance from the sensor plates 2205 to the edge of the corresponding printed circuit board.

In some embodiments, a layer of protective agent is placed on the bottom of the hard-to-see-configuration detector 2001 such that there is a layer of protective agent between the surface 2002 and the hard-to-see-configuration detector 2001. In some embodiments, the interior of the protective agent is substantially filled so that there are substantially no cavities in the protective agent. In some embodiments, the protective agent is different from felt, Velcro, cloth, or other materials that have cavities inside. The layer of protective agent can help protect the bottom of the hard-to-see-configuration detector 2001 from damage due to knocks, bumps, and abrasion. The protective agent can be made from a solid piece of material such as plastic or other non-conductive solid material. A solid layer of plastic can provide a low-friction surface on which the hard-to-see-configuration detector 2001 can slide across a wall. Although some embodiments of the hard-to-see-configuration detector 2001 do not require sliding operation, a low-friction surface can be beneficial to a user who may choose to move the hard-to-see-configuration detector 2001 by sliding it.

The protective layer of plastic can be applied by pressure sensitive adhesive, glue or other means. The layer of protective agent can be a complete layer covering the entire surface, or it can be another layer of plastic with a rectangular strip, a round piece or other geometric shape.

The protective agent, which is substantially filled to substantially eliminate voids, may generate less static charge than prior art solutions, which may advantageously provide more consistent sensor readings.

In one embodiment, the protective layer is UHMW-PE (ultra-high molecular weight polyethylene). Ultra-high molecular weight polyethylene has a low coefficient of friction. It also does not absorb much moisture, which may result in increased immunity from changes in humidity.

Figure 23 is a diagram of a circuit of a hard-to-see configuration detector 2301 according to one embodiment. The circuit includes a multiplexer 2318, a power controller 2320, a display circuit 2325, a sensing circuit 2327, and a controller 2360.

The power controller 2320 may include a power source 2322 and an on-off button 2324. The power source 2322 may include an energy source for powering the indicator 2306 as well as for powering the capacitance-to-digital converter 2321 and the controller 2360. In some embodiments, the power source 2322 may include a DC battery supply. The on-off switch 2324 may be used to activate the controller 2360 and other components of the low vision configuration detector 2001. In some embodiments, the on-off switch 2324 comprises a push button mechanism that activates the components of the low vision configuration detector 2001 for a selected period of time. In some embodiments, the push button activates the components and keeps them activated until the push button is released. In some embodiments, the on-off switch 2324 comprises a capacitance sensor that can sense the presence of a finger or thumb on the button. In some embodiments, the on-off switch 2324 may comprise a toggle switch or other type of button or switch.

The display circuitry 2325 may include one or more indicators 2306 electrically coupled to the controller 2360.

The sensing circuit 2327 may include a voltage regulator 2326 and a capacitance-to-digital converter 2321. In one embodiment, as shown in FIG. 23, the sensing circuit 2327 includes a plurality of sensors, a voltage regulator 2326, and a capacitance-to-digital converter 2321. The voltage regulator 2326 can be used to adjust the output of the power controller 2320 as desired. In one embodiment, the voltage regulator 2326 can be located as close as possible to the capacitance-to-digital converter 2321 to provide a battery power source 2322 to the capacitance-to-digital converter 2321. The sensing circuit 2327 can be electrically coupled to the controller 2360. One or more sensor plate traces 2335 or conductive paths on a printed circuit board can connect the individual sensor plates 2305 to the capacitance-to-digital converter 2321. The connection of the sensor plates 2305 to the capacitance-to-digital converter 2321 can be made via a multiplexer 2318. The multiplexer 2318 can individually connect the sensor plates 2305 to the capacitance-to-digital converter 2321.

In some embodiments, the multiplexer 2318 can connect a single sensor plate 2305 to the sensing circuitry 2327. In some embodiments, the multiplexer 2318 can connect two or more adjacent sensor plates 2305 to the sensing circuitry 2327. In some embodiments, the multiplexer 2318 can connect two or more non-adjacent sensor plates 2305 to the sensing circuitry 2327. In some embodiments, the multiplexer 2318 is configured such that the sensing circuitry 2327 measures the capacitance of one sensor plate 2305. In some embodiments, the multiplexer 2318 is configured such that the sensing circuitry 2327 measures the aggregate capacitance of two or more sensor plates 2305.

Each sensor plate 2305 of group 2307 can be independently connected to a capacitance-to-digital converter 2321 via a multiplexer 2318. In one embodiment, group 2307 itself comprises a layer of copper on a printed circuit board.

In one embodiment, a two layer printed circuit board is configured as sensor board board 2740 (see FIGS. 27 and 37). In one embodiment, a first layer of sensor board board 2740 comprises sensor board 2305 and a second layer of sensor board board 2740 comprises a shield. In one embodiment, the shield comprises a layer of copper covering the entire surface of the second layer of the printed circuit board. In one embodiment, the copper layer is covered with a non-conductive layer of solder mask. In one embodiment, holes are present in the solder mask layer. In one embodiment, the holes in the solder mask layer comprise solder pads suitable for forming solder joints.

In one embodiment, a four layer printed circuit board is formed as an interconnect board with interconnects suitable for connecting circuit components. In one embodiment, the interconnect board is configured with four layers of interconnects suitable for interconnecting the sensing circuit 2327, the controller 2360, and the display circuit 2325. In one embodiment, one side of the printed circuit board is configured for mounting components and a second side of the printed circuit board is configured with solder pads.

In some embodiments, the sensor plate 2305 is disposed on a first printed circuit board. In some embodiments, the interconnect circuit is disposed on a second printed circuit board. In some embodiments, the first printed circuit board is bonded to the second printed circuit board.

In some embodiments, there are solder pads on the sensor plate board 2740 that are complementary to the solder pads on the interconnect board. In some embodiments, the sensor plate board 2740 and the interconnect board 3751 can be stacked on top of each other and bonded together (see, for example, FIG. 37). In some embodiments, the bonding agent that bonds the two printed circuit boards together can be solder. In some embodiments, the two printed circuit boards can be bonded together using solder paste. In some embodiments, the two printed circuit boards can be bonded together with solder, and the process of bonding the two printed circuit boards together can be a standard surface mount technology (SMT) process. The standard surface mount technology process can include using a stencil to place the solder paste in the desired location. The standard surface mount technology process can include placing one printed circuit board on top of the other. In some embodiments, pins can be used to ensure proper alignment of the two printed circuit boards. In some embodiments, the final step of the surface mount technology process may involve passing the stacked printed circuit boards through a reflow path (e.g., FIG. 37 shows an interconnect board 3751 stacked on top of the sensor plate board 2740).

In one embodiment, the sensor plate 2305, shielding, and circuitry are located on a single printed circuit board. In one embodiment, a six layer printed circuit board is used. In one embodiment, the bottom six layer of printed circuit board is configured with the sensor plate 2305. The fifth layer can be the active shield. The top four layers can connect the balance of the circuitry.

In one embodiment, the sensor plate 2305, shield, and circuitry are disposed on a single printed circuit board. In one embodiment, a four layer printed circuit board is used. The first and second layers of the printed circuit board are configured with interconnect circuitry. In one embodiment, the bottom layer of the four layers of printed circuit board is configured with the sensor plate 2305. The third layer can be an active shield.

The printed circuit board can be manufactured from a variety of suitable materials, such as FR-4, FR-406, or more advanced materials used in radio frequency circuits, such as Rogers 4003C. Rogers 4003C and other radio frequency class printed circuit boards can provide improved performance over wider temperature and humidity ranges.

As used herein, the term "module" may describe a unit that may perform any given functionality in accordance with one or more embodiments of the present invention. A module may be implemented using any form of hardware or software, or a combination thereof, such as, for example, one or more processors, controllers 2360, application specific integrated circuits (ASICs), programmable logic arrays (PLAs), logic components, software routines, or other mechanisms.

The various processes for reading capacitance and converting the capacitance to a digital value, also known as capacitance-to-digital conversion, are well described in the prior art. The many different methods are not described here, and the reader is referred to the prior art for details of various capacitance-to-digital converter methods. One embodiment uses a sigma-delta capacitance-to-digital converter, such as that incorporated in Analog Devices, Inc.'s AD7747 integrated circuit. One embodiment uses a charge-sharing method of capacitance-to-digital conversion.

In one embodiment, voltage regulator 2326 may comprise an ADP150-2.65 from Analog Devices or an NCP702 from ON Semiconductor, which have very low noise. In one embodiment, controller 2360 may comprise a C8051F317 from Silicon Laboratories or any of a number of other microcontrollers.

When using the native sensor reading of the capacitance-to-digital converter 21 alone, detection of the low-vision configuration 2003 may require a high degree of accuracy, and may require greater accuracy than the capacitance-to-digital converter 2321 can provide. The native sensor reading is the raw value read from the capacitance-to-digital converter 2321, which is the digital output of the capacitance-to-digital converter 2321.

In some embodiments, native reads are performed multiple times and the multiple native read results are combined to generate a reading. In some embodiments, native reads are performed multiple times and the multiple native read results are combined using two or more native reads of different configurations to generate a reading. In some embodiments, native reads are performed multiple times and the multiple native read results are aggregated or averaged to generate a reading. In some embodiments, this improves the signal to noise ratio. Each native read may involve the reading of one sensor plate 2305. If multiple sensor plates 2305 are multiplexed to the capacitance to digital converter 2321, a native read may also involve the reading of multiple sensor plates 2305. In some embodiments, multiple native reads are combined to generate a reading.

Summing or averaging multiple native readings can improve the signal-to-noise ratio, but may not reduce the nonlinearity effects of the capacitance-to-digital converter 2321. An ideal capacitance-to-digital converter 2321 is perfectly linear, meaning that its native sensor reading increases in direct proportion to increases in sensed capacitance. However, many capacitance-to-digital converters 2321 are not perfectly linear, and changes in input capacitance may not be exactly proportional to increases in native reading. These nonlinearities can be reduced, but when a high degree of accuracy is desired, it is desirable to implement methods to reduce the nonlinearity effects.

In some embodiments, the adverse effects of nonlinearity can be mitigated by aggregating multiple native reads, with a slightly different configuration for each native read. In some embodiments, native reads are performed using two or more different configurations.

For example, bias current is one parameter that can be varied to produce different configurations. The bias current can be set to standard, standard + 20%, standard + 35% or standard + 50%. Different bias currents will produce different native sensor readings even if all other factors remain constant. Because each native reading has a different value, each native reading can possibly be subject to different nonlinearities. Perhaps instead of summing or multiplying, sensor readings subject to different nonlinearities can be summed or averaged to allow the nonlinearities to partially cancel each other out.

In some embodiments, there are two separate and independent capacitance-to-digital converters 2321. In some embodiments, each capacitance-to-digital converter 2321 may have a different nonlinearity. By utilizing both capacitance-to-digital converters 2321, using the first converter for some of the readings and the second converter for some of the readings, the effect of any single nonlinearity can be mitigated.

In one embodiment, native readings are performed on each sensor plate 2305 using 12 different configurations.

After completing the sensor readings, in some embodiments, two different calibration algorithms can be performed: the first is an individual plate calibration that adjusts for variations in the individual sensor plates 2305, and the second is a surface material calibration that adjusts the sensor reading to match the surface density/thickness. Other embodiments may use only one of these two calibration algorithms. Some embodiments may use the other calibration algorithm. In some embodiments, the calibration algorithms are performed by a calibration module.

In one embodiment, an individual plate calibration is used first. With individual plate calibration, each sensor plate 2305 can have an individual and unique calibration value. In one embodiment, after obtaining a sensor reading, the individual plate calibration value is added or subtracted from each sensor reading. In other embodiments, the individual plate calibration can be performed using multiplication, division, or other mathematical functions. In one embodiment, the individual plate calibration value is stored in non-volatile memory. The individual plate calibration compensates for irregularities in the individual sensor plates 2305, and the individual plate calibration is used to compensate for these irregularities. In one embodiment, after performing the individual plate calibration, if the sensor readings of the sensor plate are obtained while the hard-to-see configuration detector 2001 is on a surface similar to the surface 2002 on which the hard-to-see configuration detector 2301 is calibrated (see FIG. 22), it is believed that the sensor readings will likely have the same calibration value. For example, if the low vision configuration 2003 is not present and sensor readings are taken on ½ inch (½") sheetrock 2002, producing individual calibration values for ½ inch (½") sheetrock 2002, then after performing an individual board calibration, all of the sensor readings could be corrected to a common value. If the sensor readings are taken on a thicker material (e.g., 5/8 inch (5/8") sheetrock 2002), a thinner material (e.g., 3/8 inch (3/8") sheetrock 2002), or a different material (e.g., 3/4 inch (3/4") plywood), there may be some error in the values. The face material configuration may help correct this error.

In some embodiments, face material configurations can be used.

In one embodiment, after calibrating the sensor readings of the sensor plates, the hard-to-see configuration detector 2301 determines whether the hard-to-see configuration 2003 is present. In one embodiment, the lowest sensor plate reading is subtracted from the highest sensor plate reading. If this difference is greater than a threshold, it is determined that the hard-to-see configuration 2003 is present.

If it is determined that the hard-to-see configuration 2003 is not present, all indicators 2306 may be deactivated. If the hard-to-see configuration 2003 is present, the hard-to-see configuration detector 2301 begins the process of determining the position and width of the hard-to-see configuration 2003.

In some embodiments, pattern matching can be used to determine which light emitting diodes to activate. In some embodiments, a pattern matching module is used to determine the location of the low vision configuration 2003. The pattern matching module compares the calibrated and scaled sensor readings from the sensor plate 2305 to several predefined patterns. The pattern matching module determines which of the predefined patterns best matches the sensor readings. The set of indicators 2306 corresponding to the best matching pattern is then activated. Additional details regarding pattern matching are discussed in the prior art, such as U.S. Patent No. 8,884,633. Such details will not be repeated here, and instead the reader is encouraged to refer directly to such details.

In some embodiments, the low vision configuration detector 2301 includes a single capacitance-to-digital converter 2321. In some embodiments, the sensor plates 2305 can be individually connected to the capacitance-to-digital converter 2321. In some embodiments, the sensor plates 2305 can be individually connected to the capacitance-to-digital converter 2321 via the multiplexer 2318. In some embodiments, more than one sensor plate 2305 can be connected to the capacitance-to-digital converter 2321 at a time. In some embodiments, multiple adjacent sensor plates 2305 can be electrically connected to the capacitance-to-digital converter 2321. In some embodiments, multiple non-adjacent sensor plates 2305 can be connected to the capacitance-to-digital converter 2321. Because the sensor readings from each sensor plate 2305 are equally susceptible to variations in the capacitance-to-digital converter 2321, using the multiplexer 2318 to connect the sensor plates 2305 to a single capacitance-to-digital converter 2321 can improve the consistency of the sensor readings of the sensor plates 2305. Factors that may affect the sensor reading from the capacitance-to-digital converter 2321 may include, but are not limited to, process variations, temperature variations, voltage variations, electrical noise, and aging.

In some embodiments, the sensor plate traces 2335 are routed such that each of the multiple sensor plate traces 2335 has substantially equal capacitance, resistance, and inductance. In some embodiments, it is desirable for each sensor plate trace 2335 to have the same electrical properties so that each sensor plate 2305 can respond equally to the same detected object.

In some embodiments, each of the sensor plate traces 2335 from the capacitance-to-digital converter 2321 to the respective sensor plate 2305 are substantially the same length (see FIG. 25). In some embodiments, two or more of the sensor plate traces 2335 from the capacitance-to-digital converter 2321 to the sensor plate 2305 are substantially the same length. In some embodiments, sensor plate traces 2335 having substantially the same length may have more equal capacitance, inductance, and resistance. Sensor plate traces 2335 of equal length may provide better performance by improving the uniformity of sensor readings, allowing the sensor plates 2305 to respond more equally to the same detections, and providing greater immunity from environmental conditions such as temperature and humidity.

In some embodiments, each of the sensor plate traces 2335, including the conductive path, has substantially the same width. In some embodiments, both the width and length of each of the sensor plate traces 2335 are substantially equal. In some embodiments, the sensor plate traces 2335 may have multiple portions. For example, a first portion of the trace may route the sensor plate trace 2335 from the capacitance-to-digital converter 2321 to a via. The via may route the sensor plate trace 2335 to a different layer of the printed circuit board where a second portion of the sensor plate trace 2335 may reside. In some embodiments, all of the sensor plate traces 2335 may have the same length and width at each portion as the other traces in that portion. In some embodiments, two or more of the sensor plate traces 2335 may have the same width throughout the first portion. In some embodiments, two or more of the sensor plate traces 2335 may have the same width throughout the second portion. In some embodiments, two or more of the sensor plate traces 2335 can have the same length throughout the first portion. In some embodiments, two or more of the sensor plate traces 2335 can have the same length throughout the second portion.

In some embodiments, the sensor plate trace 2335 may have multiple portions. In some embodiments, the sensor plate trace 2335 portions may be wire bonds that are present in an integrated circuit package and route signals from a silicon piece to a pin on the integrated circuit package. In some embodiments, the sensor plate trace 2335 portions may comprise a copper layer on a first layer of a printed circuit board. In some embodiments, the sensor plate trace 2335 portions may comprise a copper layer on a second layer of a printed circuit board.

In some embodiments, the capacitance-to-digital converter 2321 can read the capacitance of the sensor plate 2305 and the sum of the sensor plate traces 2335. In some embodiments, it may be desirable to only detect the sensor reading on the sensor plate 2305 and not the sensor plate traces 2335. However, because the sensor plate 2305 and the sensor plate traces 2335 are electrically coupled, a means of ensuring a stable and uniform capacitance on the sensor plate traces 2335 may be desirable. For example, it may be desirable to configure the sensor plate traces 2335 such that the capacitance of the sensor plate traces 2335 is uniform and stable. Therefore, it may be preferable to configure the sensor plate traces 2335 such that the sensor plate traces 2335 do not change. In some embodiments, it may be preferable that the sensor plate traces 2335 do not change with respect to one another, and any change in capacitance on one sensor plate trace 2335 is reflected on each of the sensor plate traces 2335.

In some embodiments, it may be advantageous to shield the sensor plate traces 2335. Shielding the sensor plate traces 2335 can protect the sensor plate traces 2335 from external electromagnetic fields. Also, in some embodiments, shielding the sensor plate traces 2335 can advantageously provide a more consistent environment for the sensor plate traces 2335 by helping to ensure that each of the sensor plate traces 2335 has an environment similar to each of the other sensor plate traces 2335.

In some embodiments, each sensor plate trace 2335 from the capacitance-to-digital converter 2321 to each sensor plate 2305 has substantially the same environment. In some embodiments, the multiple sensor plate traces 2335 can be routed far enough apart to minimize capacitive and inductive coupling between the multiple sensor plate traces 2335, and each sensor plate trace 2335 can have a more similar environment to the other sensor plate traces 2335, improving the consistency of the sensor plate traces 2335. In some embodiments, one or both sides of each sensor plate trace 2335 are shielded with active shielding traces (see, for example, FIG. 25).

In some embodiments, the user 2329 may be electrically coupled to the sensing circuit 2327. In some embodiments, the quality of the sensor reading is improved when the conductive points of the sensing circuit 2327 are coupled to the user 2329. Electrically coupling the user 2329 to the sensing circuit 2327 may provide a consistent voltage level to the sensing circuit 2327, resulting in a more sensitive and higher quality sensor reading. For example, a prior art low-vision detector that drives the sensor plate 2305 with 3.0V may actually only drive the sensor plate 2305 with a signal that is 3.0V relative to ground. However, if the ground is floating, driving the sensor plate 2305 with 3.0V may result in a signal of 1.5V on the sensor plate 2305 and a signal of -1.5V on ground.

In some embodiments, electrically coupling the user 2329 to the sensing circuit 2327 may result in a higher absolute voltage amplitude on the sensor plate 2305. Part of this may be because the sensing circuit 2327 is held at a stable level. Also, in some embodiments, electrically coupling the user 2329 to the sensing circuit 2327 may result in a more consistent sensor reading.

In one embodiment, as shown in FIG. 23, the user 2329 is electrically coupled to a ground of the sensing circuit 2327. In one embodiment, the user 2329 is electrically coupled to a voltage source of the sensing circuit 2327. In one embodiment, the user 2329 is electrically coupled to a different conductive point of the sensing circuit 2327.

In some embodiments, the hand of the user 2329 may be electrically coupled to the sensing circuit 2327 by direct contact with the sensing circuit 2327. In some embodiments, a conductive material such as a wire may electrically couple the hand of the user 2329 to the sensing circuit 2327. In some embodiments, a button that the user 2329 may need to touch to activate the low vision configuration detector 2301 may include a conductive material that may be electrically coupled to the sensing circuit 2327. In some embodiments, the button may include aluminum or other conductive material such as tinned steel. In some embodiments, the aluminum button may be anodized, which may provide a pleasing cosmetic effect.

In some embodiments, the housing 2019 (see FIG. 21) of the low vision configuration detector 2301 may comprise a conductive material, such as conductive plastic. In some embodiments, only a portion of the housing 2019 may comprise conductive plastic. The conductive housing or a portion of the conductive housing may be coupled to a conductive point of the sensing circuitry 2327, thereby coupling the user 2329 to the sensing circuitry 2327.

In some embodiments, carbon black can be mixed with the plastic resin to provide electrical conductivity. Many thermoplastics, including polypropylene and polyethylene, become conductive when carbon black is mixed into the plastic resin. In some embodiments, the electrical conductivity of the plastic can be advantageously controlled, with electrical conductivity increasing as the concentration of carbon black increases. In some embodiments, a plastic having a conductivity of less than 25,000 Ω-cm is sufficiently conductive to effectively couple user 2329 to sensing circuitry 2327. In some embodiments, a high degree of electrical conductivity may be desired. In some embodiments, a lesser degree of electrical conductivity may be desired. In some embodiments, it is advantageous for user 2329 to be coupled to the sensing circuitry by a path of less than about 50 MΩ.

In some prior art low-vision configuration detectors, a change in the position of the user's 2329 hand can cause the sensor reading to change. This can occur in some prior art low-vision configuration detectors because the hand forms part of the path between the sensor plate 2305 and the ground. As a result, a change in the hand position can cause the sensor reading of the sensor plate 2305 to change. This can adversely reduce the accuracy of the sensor reading.

If the size and position of the user's 2329 hand could be made constant, then a calibration adjustment could be made that mathematically removes the effect of the user's 2329 hand from the raw sensor readings. However, this may not be feasible in practice. In practice, the sizes, shapes, and positions of the hands of various users 2329 may be too different to make a calibration adjustment practically possible.

To improve performance in view of the issues discussed above, in some embodiments, a conductive handguard may be placed between the hand of the user 2329 and the sensor plate 2305. In some embodiments, the handguard may be grounded to the sensing circuitry 2327, as shown in FIG. 23.

24 is a diagram of a controller 2360 according to one embodiment. The controller 2360 includes a processor 2461, a clock 2462, a random access memory (RAM) 2464, a non-volatile memory 2465, and/or other computer readable media. The non-volatile memory 2465 may include a program 2466 (e.g., in the form of program code or computer readable instructions for performing operations) and a calibration table 2468. In operation, the controller 2360 may receive the program 2466 and synchronize the functions of the capacitance-to-digital converter 2321 and the display circuit 2325 (see FIG. 23). The non-volatile memory 2465 receives and stores the program 2466, the look-up table, and the calibration table 2468. The program 2466 may include a number of suitable algorithms, such as, for example, an initialization algorithm, a calibration algorithm, a pattern matching algorithm, a multiplexing algorithm, a display management algorithm, an active sensor activation algorithm, and an inactive sensor management algorithm.

25 illustrates the routing of sensor plate traces 2535 for a low vision configuration detector according to one embodiment. In the embodiment illustrated in FIG. 25, each of the sensor plate traces 2535 has a substantially similar trace length, and the sensor plate traces 2535 are surrounded by active shielding traces 2536. In an embodiment, as depicted in FIG. 25, one or both sides of each of the sensor plate traces 2535 are shielded by active shielding traces 2536. In an embodiment, the active shielding traces 2536 are routed such that each side of each sensor plate trace 2535 is a constant distance from the sensor plate trace 2535. In an embodiment, the active shielding traces 2536 are substantially parallel to the sensor plate traces 2535. In an embodiment, the active shielding traces 2536 are positioned such that the active shielding traces 2536 shield the sensor plate traces 2535 from external electromagnetic fields. In some embodiments, the sensor plate traces 2535 and active shielding traces 2536 are positioned such that, for each sensor plate trace 2535 and its corresponding active shielding trace 2536, the capacitance between each sensor plate trace 2535 and each corresponding active shielding trace 2536 is substantially the same. In some embodiments, two active shielding traces 2536 are positioned along the sensor plate trace 2535, one active shielding trace 2536 on each side of the sensor plate trace 2535. In some embodiments, the sensor plate traces 2535 and active shielding traces 2536 are positioned such that there is a fixed distance between the sensor plate traces 2535 and the corresponding active shielding traces 2536 along their lengths. In some embodiments, each active shielding trace 2536 is positioned a fixed distance away from the corresponding sensor plate trace 2535. In some embodiments, a portion of each sensor plate trace 2535 and a portion of each active shielding trace 2536 comprise copper traces on a printed circuit board. In some embodiments, both the sensor plate traces 2535 and the active shielding traces 2536 are disposed on the same layer of a printed circuit board. In some embodiments, the active shielding traces 2536 are driven with a fixed voltage level. In some embodiments, the active shielding traces 2536 are driven with a voltage similar to the drive voltage for the sensor plate traces 2535.

In one embodiment, the active shielding traces 2536 may be routed along as far as possible the length of the sensor plate traces 2535 at a distance of about 0.6 millimeters from each sensor plate trace 2535. In one embodiment, the width of the sensor plate traces 2535 is about 0.15 millimeters over a portion of the sensor plate traces 2535.

In one embodiment, the shielding is configured such that there is a shielding layer above each sensor plate trace 2535 and below each sensor plate trace 2535. The shielding layer in one embodiment is a layer of copper that is on a layer adjacent to the printed circuit board. As a result, the sensor plate trace 2535 can be shielded by the layer above the sensor plate trace 2535, the layer below the sensor plate trace 2535, and the layers on either side of the sensor plate trace 2535, as described above. In one embodiment, the shielding above the sensor plate trace 2535, the shielding below the sensor plate trace 2535, and the shielding on the layers on either side of the sensor plate trace 2535 are all electrically coupled to each other.

In some embodiments, the shield is an active shield. An active shield is a shield that is driven at the same potential as the sensor plate being sensed. In some embodiments, the voltage wave driven on the sensor plate 2505 and the shield may have a triangular shape. In some embodiments, the voltage wave driven on the sensor plate 2505 and the shield may have a sinusoidal shape. In some embodiments, the voltage wave driven on the sensor plate 2505 and the shield may have a different wave shape.

Currently available low-vision configuration detectors may include a sensor plate trace that connects the sensing circuitry to the sensor plate. Some currently available low-vision configuration detectors do not use shielding to protect the sensor plate trace from interference. These detectors may be configured to keep potential interference a safe distance away from the sensor plate trace.

Other currently available low-vision configuration detectors may have shielding that can protect the sensor plate trace for a portion of the sensor plate trace's length. In one currently available low-vision configuration detector, up to 82% of the sensor plate trace's length can be protected. An example of a currently available low-vision configuration detector with shielding is shown in FIG. 38. In a currently available low-vision configuration detector with shielding, the trace may be routed such that there is a ground plane on the PCB layer below the sensor plate trace and a via that connects the portion of the sensor plate trace that is on the top PCB layer with the portion of the sensor plate trace that is on the lower PCB layer. For the portion of the sensor plate trace that is on the lower PCB layer, there is a first active shielding plane that is on the PCB layer above the sensor plate trace and a second active shielding plane that is on the PCB layer below the sensor plate trace. The first active shielding plane, the second active shielding plane, and the shielding trace are all coupled together and driven as an active shield. The active shielding may include up to 82% of the sensor plate trace's length.

In these currently available low-profile detectors, the material between the traces and the ground plane can absorb moisture. The material underneath some traces may absorb more moisture than the material underneath other traces. As a result, exposure to moisture can change the relative sensor readings of the sensor plate traces. In other words, when exposed to moisture, some sensor readings may change more than other sensor plate sensor readings due to moisture. Changes due to moisture absorbed between the traces and ground that are not due to the presence of the low-profile detector are unnecessary.

The present disclosure provides an improved low-vision configuration detector with shielding that can protect the sensor plate trace for more than 82% of the length of the sensor plate trace.

25 also shows an improved method of routing the sensor plate trace 2535, which may result in better performance. In FIG. 25, there is a very short sensor plate trace 2535 that connects the sensing circuit 2527 to the via 2534. This sensor plate trace 2535 may be only 1 or 2 millimeters long. This sensor plate trace 2535 is as short as practicable. Vias 2534 connect the portion of the sensor plate trace 2535 that is on the top layer of the printed circuit board with the portion of the sensor plate trace 2535 that is on a lower layer of the printed circuit board. For the portion of the sensor plate trace 2535 that is on the lower layer of the printed circuit board, there is a first active shielding plane 2537 that is on the layer above the sensor plate trace 2535 of the printed circuit board, and a second active shielding plane 2538 that is on the layer below the sensor plate trace 2535 of the printed circuit board. The first active shielding plane 2537, the second active shielding plane 2538 and the shielding traces are all bonded together and are all driven as an active shield.

When both the sensor plate trace 2535 and the active shield trace 2536 are driven with the same signal, the sensor plate trace 2535 and the active shield trace 2536 are at the same potential, and the capacitance between the sensor plate trace 2535 and the active shield trace 2536 may be insignificant. As a result, when the printed circuit board absorbs moisture and the dielectric constant of the printed circuit board changes, the change in the dielectric constant of the printed circuit board may have no effect on the sensor reading. The change in capacitance between the sensor plate trace 2535 and the active shield (e.g., active shield trace 2536) does not affect the sensor reading. As a result, the sensor plate trace 2535 may be able to better maintain its calibration value, and the hard-to-see configuration detector may be able to better determine the location of the hard-to-see configuration.

26 is a diagram of a sensor plate configuration of a low-vision configuration detector according to one embodiment. In this illustrated embodiment, each of the eleven various sensor plates 2605 has a similar primary sensing field zone. FIG. 26 shows a sensor plate group 2607 including eleven sensor plates 2605 and an active shield plate 2623. In this embodiment, the group 2607 of eleven sensor plates 2605 is on the bottom layer (e.g., layer 4) of a printed circuit board. In this embodiment, the active shield plate 2623 covers the entire third layer of the printed circuit board. In some embodiments, one sensor plate 2605 can be sensed at a time. In some embodiments, when sensing one sensor plate 2605, all sensor plates 2605, including the active shield plate 2623, are driven with the same signal as the sensor plate 2605 being sensed. When the group 2607 plus the active shielding plates 2623 are driven together, the field lines can be pushed deeper into the plane being sensed than would be possible if only a single sensor plate 2605 were driven. In some embodiments, this allows the field lines from a single sensor plate 2605 to penetrate deeper and sense deeper than if the single sensor plate 2605 were driven alone.

In the embodiment of FIG. 26, a sensing field can be generated by the combination of the group 2607 and the active shielding plate 2623 when both are driven with the same signal. In this embodiment, the similarity of the configuration of each of the eleven sensor plates 2605 can provide each sensor plate 2605 with a geometrically similar primary sensing zone. Similarly, each sensor plate 2605 can also have a similar sensing field within each primary sensing field zone.

26 helps provide a similar primary electric field zone for each of the sensor plates 2605. Each of the eleven sensor plates 2605 has a similar outer boundary 2611. Each of the eleven sensor plates 2605 also has a similar area and a similar inner boundary 2610. Each of the eleven sensor plates 2605 also has a similar electrical environment. Each sensor plate 2605 is surrounded on both sides by other sensor plates 2605 or active shielding plates 2623. Both the active shielding plates 2623 and adjacent sensor plates 2605 can be driven in the same way, so that the active shielding plates 2623 and adjacent sensor plates 2605 can each provide a comparable electrical environment. As a result, each of the eleven sensor plates 2605 in FIG. 26 can have a geometrically similar primary sensing field zone.

The shapes of the eleven sensor plates 2605 in FIG. 26 are not identical. While it would be ideal to have the eleven sensor plates 2605 identical, adjustments are made to four of the eleven sensors 2605 (two sensor plates 2605 on each side) to obtain more similar primary sensing field zones. In this embodiment, achieving a more similar primary sensing field zone may be more desirable than having identical sensor plate geometries. Nevertheless, all eleven sensor plates 2605 may have substantially the same area, the same outer boundary 2611, a similar inner boundary 2610 configuration, and a similar electrical environment. Such a configuration with these similarities may provide each sensor plate 2605 with a comparable primary sensing field zone.

In some embodiments, it may be beneficial to have a similar electrical environment that extends beyond the inner boundary 2610 of the sensor plate 2605 for 1 to 1.5 times the desired sensing depth. For example, if a sensing depth of 1 inch (25.4 millimeters) is desired, it may be beneficial to have a similar electrical environment around each sensor plate 2605 that extends 1 to 1.5 inches beyond the inner boundary 2610 of each sensor plate 2605.

27 is a cross-sectional view of a low vision configuration detector including a housing 2719, light pipes 2708 and buttons 2724, and a printed circuit board 2740, according to one embodiment. In an embodiment, as depicted in FIG. 27, the housing 2719 includes an upper housing, an on-off switch 2724, a handle 2714, a plurality of light pipes 2708, and a power compartment. In an embodiment, a compliant core (see compliant core device 3449 in FIG. 34) can be configured to flexibly couple the housing 2719 to the sensor board board 2740. In an embodiment, the sensor board board 2740 is a multi-layered printed circuit board having a top layer 2744, a second layer 2743, a third layer 2742, and a bottom layer 2741. In an embodiment, the sensor board board 2740 is a multi-layered printed circuit board that couples the capacitance-to-digital converter 2321, the display unit 2325, and the controller 2360, as described above with reference to FIG. 23. In some embodiments, the housing 2719 comprises plastic. In some embodiments, the housing 2719 comprises ABS (Acrylonitrile Butadiene Styrene) plastic. In some embodiments, a conductive hand guard 2756 shields the user's hands from the sensor plate board 2740. In some embodiments, the hand guard 2756 is connected to the ground of the sensing circuit.

In some embodiments, the handle 2714 includes a gripping surface. In some embodiments, a portion of the gripping surface includes an elastomer that makes the handle 2714 easier to grip. The handle 2714 is preferably positioned so as not to obscure a view of the indicator 2706 when a user's hand is gripping the handle 2714. In some embodiments, the power compartment includes a cavity for holding a suitable power source, such as a battery, and a battery cover for accessing the compartment.

In some embodiments, the hand guard 2756 may be configured such that there is no significant linear path between the sensor plate and the user's hand. In some embodiments, the housing 2719 may be constructed from a conductive material that may comprise the hand guard 2756. In some embodiments, the conductive layer of material of the hand guard 2756 may be a layer of conductive plastic. In some embodiments, the conductive layer of material of the hand guard 2756 may be a layer of a different conductive material, such as conductive paint. In some embodiments, the conductive layer of material of the hand guard 2756 may be a sheet of metal hidden within the housing 2719. In some embodiments, the hand guard 2756 may include tin-plated steel, which may provide a quick, easy, and reliable solder joint. In some embodiments, an entire layer of a printed circuit board may comprise the hand guard 2756. In some embodiments, only a portion of a layer of a printed circuit board may comprise the hand guard 2756, as it may not be necessary to include an entire layer for the hand guard 2756. For example, a ring around the outside of the printed circuit board may be the effective hand guard 2756.

In some embodiments, the hand guard 2756 is configured to minimize the effect of hand size and position. In some embodiments, the hand guard 2756 is positioned so that the hand guard 2756 is close to the hand, since in some embodiments the hand guard 2756 may be most effective when it is closest to the hand. In some embodiments, the hand guard 2756 may be electrically coupled to the ground of the sensing circuit 2327 (see FIG. 23). In some embodiments, the hand guard 2756 may be coupled to the potential of the sensing circuit 2327. In some embodiments, different conductive points of the sensing circuit 2327 may be electrically coupled to the hand guard 2756. In some embodiments, an electrical wire comprises an electrical path between the hand guard 2756 and the sensing circuit 2327.

FIG. 28 shows a sensor plate group 2801 having four sensor plates 2805. In an embodiment, as depicted in FIG. 28, the sensor plate group 2801 may include four similar sensor plates 2805. In the embodiment depicted in FIG. 28, each triangular sensor plate 2805 has two sides that form an inner boundary 2810 and one side that forms an outer boundary 2811. In FIG. 28, each of the four sensor plates 2805 is radially symmetrical. From these four sensor plates 2805, three different sensing zones may result. For example, if a vertical stud is placed in any position relative to the sensor plate 2805, three different readings may appear. Each reading is for one of the three sensing zones. The first zone may correspond to the left sensor plate. The second zone may correspond to the top and bottom sensor plates (e.g., it can be understood that the top and bottom sensor plates will have the same readings because they can each sense the same portion of the vertical stud). The third zone may correspond to the right sensor plate. The relative readings for each of the three zones may be used to determine the location of the vertical stud.

29 illustrates a sensor plate group 2901 having six sensor plates 2905. In an embodiment, as depicted in FIG. 29, the sensor plate group 2901 may include six similar sensor plates 2805. In the embodiment depicted in FIG. 29, each sensor plate 2905 is triangular, each having two straight sides forming an inner boundary 2910 and one straight side forming an outer boundary 2911. In an embodiment, each sensor plate 2905 has substantially the same area.

Figures 30-32 are diagrams of a prior art hard-vision detector. In a prior art hard-vision detector, a set of identical sensor plates 3005 are typically arranged in a linear fashion, as shown, for example, in Figures 30, 31, 32, and 33. Figure 30 is a prior art hard-vision detector 3001 arranged on a relatively thinner surface 3012. Figure 31 is a prior art hard-vision detector 3001 arranged on a relatively thicker surface 3113. Figure 32 shows a side view of the prior art hard-vision detector 3001, illustrating the primary sensing field zones 3215, 3216, 3217 for several sensor plates 3005, including sensor plates A, B, C, D, and E. Figure 33 shows a front view of the bottom surface of the prior art hard-vision detector 3001, illustrating the primary sensing field zones 3215, 3216, 3217 for sensor plates A, B, C, D, and E.

Referring generally and collectively to Figures 30-33, each sensor plate 3005 takes a sensor reading for a surface to detect a difficult-to-see structure behind that surface. The sensor readings are then compared. The sensor plate 3005 with the highest reading is determined to be at the location of the difficult-to-see structure. However, as depicted in Figures 30 and 31, sensor plates 3005 near the ends of the group may not respond to the difficult-to-see structure in the same way as sensor plates 3005 near the center. This problem may be particularly evident when the prior art difficult-to-see structure detector 3001 moves from a thinner surface to a thinner or less dense surface 3012 to a thicker or more dense surface 3113.

Figure 30 represents a typical sensor reading of a prior art low-vision detector 3001 placed on a relatively thin surface 3012. The relatively thin surface 3012 may be 0.375 inch (9.525 mm) thick sheetrock. Figure 31 represents a typical sensor reading of a prior art low-vision detector 3001 placed on a relatively thick surface 3113. The relatively thick surface 3113 may be 0.625 inch (15.875 mm) thick sheetrock.

In FIG. 30, the prior art hard-to-see configuration detector 3001 is placed on a relatively thin surface 3012. Each sensor plate 3005 may have a calibration adjustment so that each has a calibrated reading (e.g., 100). If this same prior art hard-to-see configuration detector 3001 were then moved to another surface 3113 that is thicker or has a higher dielectric constant, the sensor reading would change. The same prior art hard-to-see configuration detector 3001 on the thicker surface 3113 is shown in FIG. 31. Ideally, in the absence of hard-to-see configuration, the multiple sensor plates 3005 would all be on the same thicker surface 3113, so that each of the sensor plates 3005 on the thicker surface 3113 would have a similar sensor reading to each other. However, it can be observed that the sensor readings of the sensor plates 3005 near the edges produce a larger reading than the sensor plates 3005 near the center. In FIG. 31, it can be seen that the sensor plate 3005 near the center has a sensor reading of 200, while the sensor plate 3005 at the end has a sensor reading of 250.

In the prior art hard-to-see configuration detector 3001 of FIG. 31 and other prior art hard-to-see configuration detectors, the sensor plates 3005 present at the edge become isolated as they generate an electric field 3009 that extends above the edge of the group of sensor plates 3005. As a result, the sensor plates 3005 near the edge may respond with disproportionately higher readings when placed on a thicker surface 3113. The controller 2360 may have adversely difficulty determining whether the elevated sensor reading is due to the presence of a hard-to-see configuration or due to the prior art hard-to-see configuration detector 3001 being placed on a thicker surface 3113. The disclosed embodiments may address these and other challenges.

Figure 32 shows field lines for the prior art low vision configuration detector 3001 of Figures 30 and 31. Figure 32 shows a group of sensor plates 3005 and a two-dimensional representation of the field lines for each sensor plate 3005. The field lines are shown for illustrative purposes and are representative of the actual sensing field. The field lines depicted are equipotential electric field lines. However, this diagram does not limit the scope of the disclosure to only this type of field. Vector electric field lines or magnetic field lines can be depicted and are within the scope of the disclosure. The sensing field can be an electromagnetic field, which is an electric field or a magnetic field or a combination of electric and magnetic fields.

In FIG. 32, there are thirteen sensor plates 3005. All of the sensor plates 3005 can be driven simultaneously by the same signal, while one sensor plate 3005 is sensed at a time. Because the sensor plates 3005 are driven simultaneously by the same signal, the sensing field is defined by the fields produced by the group of sensor plates 3005, as shown in FIG. 32. Active shielding planes are not shown, but in some embodiments active shielding may contribute to the sensing field. Five of the sensor plates 3005 are labeled A, B, C, D, and E. The field lines emanating from sensor plate E are essentially parallel to sensor plate E. However, the field lines emanating from sensor plate A are not quite parallel to sensor plate A. These field lines are not similar in direction and intensity at each point within the primary sensing field zone, so sensor plates A and E do not have similar sensing fields within these primary sensing field zones.

In contrast, sensor plate D and sensor plate E have similar primary sensing field zones because the volumes of the sensing fields that sensor plate D and sensor plate E can effectively sense and the sensing fields within the primary sensing field zones are similar. The sensing fields within the primary sensing field zones are similar when the direction of the sensing field and the intensity of the sensing field are similar at each point within the primary sensing field zone.

Figure 33 shows the same concept from a different angle or perspective. In Figure 33, the five sensor plates 3005 are again referred to as A, B, C, D, and E. The approximate primary sensing field zones for each of the sensor plates 3005 are highlighted. On the two-dimensional view of Figure 33, the primary sensing field zone 3215 for sensor plate A is shown by a drawing of the sensing field lines for sensor plate A. On the two-dimensional view of Figure 33, the primary sensing field zone 3216 for sensor plate B is shown by a drawing of the sensing field lines for sensor plate B. On the two-dimensional view of Figure 33, the primary sensing field zone 3217 for sensor plate C is shown by a drawing of the sensing field lines for sensor plate C.

32 and 33 show the primary sensing field zones in a two-dimensional view. However, in reality, there may be three-dimensional primary sensing field zones. For each sensor plate 3005, there may be a three-dimensional zone that includes the primary sensing field zone for each given sensor plate 3005. In contrast to the prior art embodiment of FIGS. 32 and 33, in certain embodiments of the present disclosure, the sensor plates 3005 may have equivalent primary sensing field zones. Each sensor plate 3005 of a group with equivalent primary sensing field zones responds equally to changes in surface. The present disclosure shows several configurations in which each sensor plate 3005 of a group may have equivalent primary sensing field zones. In certain embodiments, each sensor plate 3005 with similar primary sensing field zones may have similar sensor reading changes in response to changes in the detected surface. In certain embodiments, in a group of sensor plates 3005, the sensor plates 3005 are each radially symmetrical.

Figure 34 is a side view of a chassis of an adaptive core device 3449 of a surface-adapted low-vision configuration detector according to one embodiment. Figure 35 is a perspective view of the chassis of the adaptive core device 3449 of Figure 34.

The present disclosure provides various embodiments of surface-conforming hard-view configuration detectors. Conventional detectors have sensor plates 2205 that are rigidly connected together, so that the dimensions of the hard-view configuration detectors generally remain relatively small to function on curved surfaces that are typical of many architectural surfaces. The surface-conforming hard-view configuration detectors disclosed herein can be larger configuration detectors that can conform to the contours of the surface, minimize air gaps, and provide various performance improvements. The improvements described in this disclosure can be applied to both the relatively small conventional detectors and the larger configuration detectors.

In some embodiments, the low-vision configuration detector has one or more flexible printed circuit boards (such as sensor plate board 2740) that can bend to conform to the contours of the surface to be detected. A flexible printed circuit board comprises a flexible substrate. Other flexible substrates can also be used, which can be made of wood, paper, plastic, or other flexible materials. Rigid-flexible printed circuit boards can also be used.

One or more printed circuit boards can be flexibly connected to the housing 2019 using a flexible medium (such as foam rubber, springs, gel, hinges, pivots, encapsulated fluids such as air, or other suitable compressible or flexible medium). In some embodiments, the housing 2019 can be flexible. In some embodiments, the housing 2019 is partially flexible. In some embodiments, the housing 2019 has integrated plastic leaf springs or other types of springs or configurations that provide flexibility. In some embodiments of the low vision configuration detector 2001, the sensor plate 2205 can be mounted on a printed circuit board, which is mounted to the outside of the housing 2019. In some embodiments, the printed circuit board is connected to the housing 2019 via a foam rubber ring. In some embodiments, the foam rubber ring is approximately 7 millimeters thick and formed in the approximate shape of a ring that is approximately 6 millimeters wide along its long side and approximately 5 millimeters thick along its short side, and approximately follows the circumference of the housing 2019. A permanent adhesive, such as a pressure sensitive acrylic adhesive, can be used to adhere the foam rubber ring to the housing 2019 and the printed circuit board.

In some embodiments, the foam rubber ring is compressible and the printed circuit board is flexible, allowing the low-vision configuration detector 2001 to conform to the curvature and irregularities of the surface 2002 against which it is placed. Various flexible and/or compressible materials may be suitable for the flexible medium. Ethylene Propylene Diene Monomer (EPDM) foam rubber rated to compress 25% under a pressure of 1.5 pounds per square inch (10,342.14 Pa) may be used. Other types of foam rubber, such as polyurethane foam or silicone rubber foam, may also be used. In some embodiments, it is desirable for the flexible medium attached between the printed circuit board and the housing 2019 to be non-conductive or partially conductive to the extent that it does not interfere with the operation of the low-vision configuration detector 2001.

In some embodiments, the compliant core device 3449 can flexibly connect the housing 2019 to the printed circuit board, as shown, for example, in FIGS. 34 and 35. In some embodiments, the compliant core device 3449 can have two or more pivots 3452. In some embodiments, the pivots 3452 are flexible joints. In some embodiments, the pivots 3452 are ball joints. In some embodiments, the pivots 3452 are hinges. In some embodiments, the pivots 3452 are living hinges. A living hinge is a thin, flexible hinge that is made from the same material as the two rigid parts it connects. In some embodiments, the pivots 3452 can be any of a number of other flexible mechanisms.

34 and 36, the adaptive core device 3449 includes a main shaft 3453. In some embodiments, the main shaft 3453 includes an axle member. In some embodiments, the main shaft 3453 includes an axle member and two pivots 3452. In some embodiments, each pivot 3452 of the main shaft 3453 connects the main shaft 3453 to a minor shaft 3454. In some embodiments, each minor shaft 3454 includes an axle member and three pivots 3452. In some embodiments of the minor shafts 3454, there is one pivot 3452 near the center of each minor shaft 3454 and two additional pivots 3452, one at each end of each minor shaft 3454. In some embodiments, there are four feet 3455 that connect to the main shaft 3453. In some embodiments, each foot 3455 has a pivot 3452. In one embodiment, the pivot 3452 is coupled to a pivot 3452 of each of the four feet 3455 at each end of the two small shafts 3454. In one embodiment, each foot 3455 is coupled to a printed circuit board. In one embodiment, the printed circuit board can bend to conform to the contours of the surface 2002.

In one embodiment, as shown in Figures 34 and 35, the feet 3455 couple the printed circuit board to the spindle 3454.

In some embodiments, the compliant core device 3449 includes a major axis 3453, two minor axes 3454, and four feet 3455. In some embodiments, there are six pivots 3452 in the compliant core device 3449. In some embodiments, there are seven or more pivots 3452. In some embodiments, there are fewer than six pivots 3452.

In one embodiment, as shown in FIG. 35, all of the pivots 3452 are living hinges and the entire compliant core device 3449 comprises a single injection molded plastic part.

36 is a flow diagram of a method 3600 for detecting poor vision configurations behind a surface according to one embodiment. As shown in the flow diagram of FIG. 36, a first operation can be initialization of the detector (3602), which can involve running an initialization algorithm. The detector can follow one embodiment described herein. After initialization, the sensor plates can be read (3604). In one embodiment, each sensor plate can be read multiple times, each time using a different configuration. The different configurations can include different drive currents, different voltage levels, different sensing thresholds, or other different configuration parameters. Each of these readings of the sensor plate can be referred to as a native read. In one embodiment, multiple native readings are added together to generate a reading. In one embodiment, there can be a separate reading for each sensor plate.

In one embodiment, each of these readings undergoes a calibration adjustment (3606), which is accomplished by adding a predetermined calibration value to each reading. In one embodiment, after calibration, the readings for each of the sensor plates can be equal if the detectors are placed on a uniform surface.

In some embodiments, the highest sensor plate reading is compared (3608) against the lowest sensor plate reading. This difference is then compared (3608) to a threshold. In some embodiments, if the difference is less than a predetermined threshold, all indicators may be turned off (3610) to indicate that no stud is present. If the difference is greater than a predetermined threshold, a determination may be made as to which indicators to activate. In certain embodiments, the readings may be scaled (3612) to a predetermined range, which may involve setting the lowest value to a number such as 0 and scaling the highest reading to a value such as 100. All intermediate values may then be scaled proportionally. The scaled reading may then be compared (3614) against a predetermined pattern that is also scaled.

In some embodiments, there may be a set of predefined patterns. The set of predefined patterns may correspond to various combinations of hidden configurations that the detector may encounter. For example, the set of predefined patterns may correspond to various locations for a single stud. In some embodiments, the set of predefined patterns may include combinations of locations of two studs. A pattern matching algorithm may be used to determine which of the predefined patterns best matches the reading pattern. The detector may then activate an indicator that corresponds to the best matching predefined pattern (3616).

In another embodiment, after calibrating the sensor plate readings, it is determined whether a hard-to-see configuration is present. The lowest sensor plate reading can be subtracted from the highest sensor plate reading. If this difference is greater than a threshold, it is determined that a hard-to-see configuration is present. If it is determined that a hard-to-see configuration is not present, all indicators can be deactivated. If a hard-to-see configuration is present, the process can begin to determine the location and width of the hard-to-see configuration. In one embodiment, all current sensor plate readings can be scaled, with the lowest reading scaled to a predetermined value (e.g., 0) and the highest reading scaled to a second predetermined value (e.g., 100). All intermediate values can be scaled proportionally. The scaled readings can be more easily compared against a set of predefined patterns.

FIG. 37 illustrates two different printed circuit boards in a stacked configuration according to one embodiment of the disclosure. The sensor board board 3740 and the interconnect board 3751 can be stacked on top of each other and bonded together. The sensor board board 3740 can include one or more sensor boards. The interconnect board 3751 can include multiple indicators 3706. The sensor board board 3740 and/or the interconnect board 3751 can be multiple printed circuit boards or can be integrated into a printed circuit board. In some embodiments, the bonding agent that bonds the two printed circuit boards 3740, 3751 together can be solder. In some embodiments, the two printed circuit boards 3740, 3751 can be bonded together using solder paste. In some embodiments, the two printed circuit boards 3740, 3751 can be bonded together with solder, and the process of bonding the two printed circuit boards 3740, 3751 together can be a standard surface mount technology (SMT) process. A standard surface mount technology process may involve placing one printed circuit board on top of the other. In some embodiments, pins may be used to ensure proper alignment of the two printed circuit boards 3740, 3751. In some embodiments, the final step of the surface mount technology process may involve passing the stacked printed circuit boards 3740, 3751 through a reflow path.

In other embodiments, both the sensor plate and the circuitry may be assembled on a single printed circuit board. A 1.6 mm thick printed circuit board containing four layers of copper may be used. In one embodiment, a first layer of copper is on the top surface with all of the electrical components soldered to that layer. A second layer of copper may be located approximately 0.35 mm below the first layer of copper with approximately 0.35 mm of printed circuit board between the first and second layers of copper. A third layer of copper may be located approximately 0.1 mm below the second layer of copper with approximately 0.1 mm of printed circuit board between the second and third layers of copper. A fourth layer of copper may be located approximately 0.35 mm below the third layer of copper with approximately 0.1 mm of printed circuit board between the third and fourth layers of copper. In one embodiment, vias may be drilled to selectively connect the four layers of copper.

In some embodiments, a final 0.8 mm thick layer of substrate material can be placed to cover the four copper layers. In some embodiments, no holes are drilled through the 0.8 mm thick layer of substrate. The 0.8 mm thick layer of substrate can help protect the circuitry from electrostatic discharge. Alternatively, a layer of plastic or other non-conductive material can be used to shield the circuitry from electrostatic discharge and to physically protect the printed circuit board. In some embodiments, a layer of plastic can be used in addition to the protective layer of the circuit board. It is understood that the layers and thicknesses shown herein are merely exemplary of one embodiment. Other layer and thickness and material combinations can be used.

In some embodiments, the sensor plate may be disposed over four layers of copper. A shield may be used to electrically protect the sensor plate from electrical interference from ambient conditions (including the user's hands). In some embodiments, the shield may be disposed over the first layer of copper. In some embodiments, instead of using a mesh, stripes, or other pattern that may provide less than substantially all of the area of shielding, a solid shield may cover substantially all of the area of shielding.

In one embodiment, the conductive path connecting the sensor plate to the capacitance-to-digital converter includes a sensor plate trace. In one embodiment, the sensor plate trace is disposed primarily on the second copper layer, and signal shielding is disposed on the first and fourth copper layers.

In some embodiments, the interconnect board 3751 that is soldered to the sensor plate board 3740 is coated with a layer of epoxy, a glob of epoxy, or other conformal coating that can improve the reliability of the solder joints. In some embodiments, the interconnect board 3751 on the sensor plate board 3740 is wire bonded to a printed circuit board by chip-on-board technology. Chip-on-board technology can involve (1) attaching a bare die to a printed circuit board, (2) wire bonding (electrically connecting the signals on the bare die to the printed circuit board), and (3) coating the bare die and wire bonds with a coating of epoxy or other suitable material. Chip-on-board technology can improve the reliability of the solder joints.

In some embodiments, an integrated circuit is used having a package that includes external leads, such as a QFP package, a TSOP package, a SOIC package, a QSOP package, or other package. Components with external leads can improve the reliability of the solder joints.

38 shows a prior art arrangement for routing and protecting the sensor plate trace 3835 from the controller of the sensing circuit 3827 to the sensor plate 3805. In this prior art, the sensor plate trace 3835 is routed such that there is a ground plane 3833 on the printed circuit board below the sensor plate trace 3835. Vias 3834 connect the portion of the sensor plate trace 3835 that is on the top layer of the printed circuit board with the portion of the sensor plate trace 3835 that is on a lower layer of the printed circuit board. For the portion of the sensor plate trace 3835 that is on the lower layer of the printed circuit board, there is a first active shielding plane 3837 that is on a layer of the printed circuit board above the sensor plate trace 3835 and a second active shielding plane 3838 that is on a layer of the printed circuit board below the sensor plate trace 3835. The first active shield plane 3837, the second active shield plane 3838 and the shield trace 3836 are all coupled together and driven as an active shield. Prior art active shields can include up to 82% of the length of the sensor plate trace 3835.

In these prior art detectors, the material between the sensor plate traces 3835 and the ground plane 3833 can absorb moisture. The material underneath some of the sensor plate traces 3835 can absorb more moisture than the material underneath other sensor plate traces 3835. As a result, exposure to moisture can change the relative sensor readings of the sensor plate traces 3835. In other words, when exposed to moisture, the sensor readings of some sensor plates 3805 can change more than the sensor readings of other sensor plates 3805 due to moisture. Changes due to moisture absorbed between the sensor plate traces 3835 and ground that are not due to the presence of a low-visibility configuration are unnecessary. In accordance with the present disclosure, an improved low-visibility configuration detector can protect the sensor plate traces 3835 for more than 82% of the length of the sensor plate traces 3835.

39 is a cross-sectional view of a hard-to-see configuration detector 3901 according to another embodiment, showing the electric field pattern. FIG. 39 illustrates the direction of the electric field lines 3904, 3905 according to the embodiment described above, where the electric field lines 3904, 3905 curve around the side of the hard-to-see configuration detector 3901. FIG. 39 illustrates a hard-to-see configuration detector 3901 with electric field lines 3904, 3905 extending from a sensor plate 3908 and terminating on a common plate 3906, 3907. The sensor plate 3908 is disposed at the bottom of the hard-to-see configuration detector 3901, and the common plates 3906, 3907 are disposed on the side of the hard-to-see configuration detector 3901. A shielding plate 3909 (e.g., an active shield) is placed between the sensor plate 3908 and the common plates 3906, 3907, causing the electric field lines 3904, 3905 to extend down, out and up around the sides of the low-vision configuration detector 3901.

The common plates 3906, 3907 can include a single plate or multiple different plates electrically connected to maintain a uniform voltage while the common plates 3906, 3907 extend along various sides of the low-vision detector 3901. To ensure that the electric field lines 3904, 3905 do not extend in a straight line from the sensor plate 3908 to the common plates 3906, 3907 or penetrate the low-vision detector 3901, a shielding plate 3909 can be positioned between the sensor plate 3908 and the common plates 3906, 3907. The shielding plate 3909 can hold the same charge or voltage as the sensor plate 3908, and the capacitance between the shielding plate 3909 and the sensor plate 3908 can be insignificant. If the shielding plate 3909 has the same voltage or charge as the sensor plate 3908, the electric field lines 3904, 3905 from the sensor plate 3908 will curve around the shielding plate 3909 to reach a plate having a different potential (e.g., common plate 3906, 3907) without being attracted to the shielding plate 3909. The shielding plate 3909 may be advantageously positioned to direct the electric field lines 3904, 3905 around an edge or side of the low vision configuration detector 3901. For example, in one embodiment, the shielding plate 3909 may be placed on a layer directly above the sensor plate 3908, covering the entire area of the sensor plate 3908. In one embodiment, the shielding plate 3909 may then extend around the edge (or tip) of the sensor plate 3908 and may extend underneath itself until the portion of the shielding plate 3909 that extends above the sensor plate 3908 is in the same plane as the sensor plate 3908. The portion of the shielding plate 3909 that is in the same plane as the sensor plate 3908 can then extend to the tip of the low-vision detector 3901, thereby forming a lip 3910 around the sensor plate 3908. Ideally, the shielding plate 3909 can reach from the sensor plate 3908 to the common plates 3906, 3907 only by bending the electric field lines 3904, 3905 around the sides of the low-vision detector 3901.

In some applications, it may be desirable to have the electric field lines 3904, 3905 diverge from the hard-to-see configuration detector 3901 so that the electric field lines 3904, 3905 curve around the sides of the hard-to-see configuration detector 3901. If the electric field lines 3904, 3905 curve around the sides of the hard-to-see configuration detector 3901, they may be able to penetrate further into the plane than if they were limited to the area immediately in front of the sensor plate, which may result in the sensor plate 3908 providing more accurate or more consistent readings. In some applications, it may be desirable to sense around the sides of the hard-to-see configuration detector 3901, rather than just directly in front of the sensor plate 3908.

40 is a cross-sectional view of a low-vision configuration detector 4001 according to another embodiment, showing the electric field pattern. FIG. 40 depicts the direction of the electric field lines 4004, 4005 curving out, over and around the sides of the low-vision configuration detector 4001. The low-vision configuration detector 4001 includes a housing 4019 and a sensor board 4040 (e.g., a printed circuit board). In some embodiments, the housing 4019 may include an upper housing, an on-off switch 4024, a handle 4014, and a number of light pipes 4018. The sensor board 4040 may be a multi-layered printed circuit board having a top layer 4044, a second layer 4043, a third layer that may be an active shield 4009, and a bottom layer that includes the sensor board 4008. Additional components of the sensor board 4040 may include those described in connection with FIG. 23.

Figure 40 shows a hard-to-see configuration detector 4001 forming electric field lines 4004, 4005 extending from a sensor plate 4008 and terminating on one or more common plates 4006. The sensor plate 4008 is positioned at the bottom of the hard-to-see configuration detector 4001, and the one or more common plates 4006 are positioned on a different plane than the sensor plate 4008 so as to be positioned at a greater distance from the plane through which the hard-to-see configuration detector 4001 can detect the hard-to-see configuration. The common plate 4006 can include a single plate or multiple different plates electrically connected to maintain a uniform voltage. A shielding plate 4009 (e.g., an active shield) is positioned between the sensor plate 4008 and the common plate 4006. An electric field (due to electric field lines 4004, 4005, respectively) is formed between the sensor plate 4008 and the common plate 4006, and the shielding plate 4009 extends the electric field lines 4004, 4005 down, out, and up around the sides of the low vision configuration detector 4001. As described elsewhere, the shielding plate 4009 restricts the electric field lines 4004, 4005 from extending in a straight line from the sensor plate 4008 to the common plates 4006, 4007.

The shielding plate 4009 may be an active shield driven with the same charge or voltage as the sensor plate 4008, so that the capacitance between the shielding plate 4009 and the sensor plate 4008 is small and has no effect on the sensing of the sensor plate 4008. If the shielding plate 4009 has the same voltage or charge as the sensor plate 4008, the electric field lines 4004, 4005 generated from the sensor plate 4008 will not be attracted to the shielding plate 4009 and will not curve around the shielding plate 4009 to reach a plate with a different potential (such as the common plate 4006). As described, the shielding plate 4009 may be advantageously positioned to direct the electric field lines 4004, 4005 down and then out and around the edge or side of the low vision configuration detector 4001. For example, in one embodiment, the shielding plate 4009 can be positioned on a layer directly above the sensor plate 4008 (away from the surface through which the low-vision configuration detector 4001 can detect objects) to cover the entire area of the sensor plate 4008.

By configuring the electric field lines 4004, 4005 to curve on the sides of the hard-to-see configuration detector 4001, the electric field lines 4004, 4005 can penetrate further into the object being sensed 4090 and/or further into the plane to sense hard-to-see objects than if the electric field lines 4004, 4005 were limited just in front of the sensor plate. By penetrating the electric field lines 4004, 4005 deeper, the sensor plate 4008 can provide more accurate and/or consistent readings, particularly of changes in the thickness of the object being sensed 4090 and/or the thickness of the detection surface.

Embodiments herein can be used for a variety of purposes other than detecting hard-to-see configurations. FIG. 40 provides an example of using an embodiment of a hard-to-see configuration detector 4001 to sense an object 4009. For example, in a manufacturing or production line environment involving the handling or testing of biological materials, the disclosed embodiments can be utilized to detect whether an electrochemical characteristic of a product has changed. As a further example, if the product at hand is a type of product such as a fruit or vegetable, the dielectric properties of the product (e.g., the relative static permeability of the product) may change as the product decomposes or the ripeness of the product changes. Since capacitance is a function of the relative static permeability (otherwise known as the dielectric constant) between two capacitive plates of a material, the capacitance measured by an embodiment may change as products of different ripeness pass through the sensing field. In this example, a hard-to-see configuration detector according to an embodiment of the present disclosure can be used to sense whether the ripeness of a product is within a desired specification. Because a hard-to-see configuration detector can use multiple sensor plates, the measurement can provide a more detailed analysis than if only a single pair of capacitive plates were used.

Other applications of the disclosed embodiments may involve investigating the electrical properties of various materials. In some situations, it may be important to measure certain electrical properties of a material without changing the location, shape, or structural integrity of the material. The disclosed embodiments may measure capacitance on or near the material at hand, and perhaps compare the measurements against measurements of a reference sample. The measured capacitance, or the difference in capacitance when compared against a reference sample, may provide various details about the electrical properties of the material at hand.

The disclosed embodiments can also be used to provide details regarding the curvature or shape of a surface. When utilizing the disclosed embodiments along a curved or angled surface, for example, the sensor plate reading may yield different values depending on the distance of the sensor plate from the surface. From the variation in sensor values, the disclosed embodiments may be able to provide insight into the slope or angle of the surface.

The sensor value may also vary depending on the texture of the material within the sensing field. For example, if the material at hand is porous, granular, rough, smooth, fibrous, or textured, the disclosed embodiments may be utilized to provide textured detail. In some applications, the disclosed embodiments may be used to infer things regarding the density of a given material, as well as to determine other quality characteristics of the product that depend on the dielectric constant of the product.

Other applications of the disclosed embodiments may involve determining whether a container is filled to an appropriate level or has an appropriate amount of items.

41 is a diagram of a sensor plate cluster 4100 including a sensor plate 4013, an active shielding plate 4102, an active shielding core 4101, and a common ring 4105. FIG. 41 shows eight sensor plates 4103. The sensor plates 4103 are arranged radially around a central location. In operation, the sensor plates 4103, the active shielding plates 4102, and the active shielding core 4101 are all driven simultaneously by a common signal. The sensor plates 4103, the active shielding plates 4102, and the active shielding core 4101 may not be electrically coupled to each other, but because they are each driven by the same signal, the electric field they generate can be comparable to the electric field that would be generated if they were coupled to each other. The sensor plates 4103, the active shielding plates 4102, and the active shielding core 4101 together can form a first end of a common electric field.

There is a common ring 4105 that can form a second end of the common electric field. In some embodiments, the common ring 4105 is driven at 0 volts. In other embodiments, the common ring 4105 can be driven with a different constant or alternating voltage. There is a common electric field generated by the sensor plate 4103, the active shielding plate 4102, and the active shielding center 4101, all driven together, but each component still contributes a certain part of the common electric field. For example, a portion of the electric field driven from the sensor plate 4103 on the lower left side of the sensor plate cluster 4100 can be located primarily on the lower left side of the sensor plate cluster 4100. For example, the field lines from the lower left sensor plate 4110 can originate at a particular sensor plate 4110. The field lines from the active shielding center 4101, the field lines from the active shielding plate 4102, and the field lines from the neighboring sensor plates can surround the field lines from the lower left sensor plate 4110. This is as if the field lines from the bottom left sensor plate 4110 are guided by the field lines from the surrounding components of the sensor plate cluster 4100. For example, the field lines from neighboring sensor plates may border the field lines of the bottom left sensor plate 4110 on both sides. The field lines from the active shield plate 4102 may border the field lines from the bottom left sensor plate 4110 at the top (the top being the portion of the field furthest from the plane of the sensor plate). Similarly, the field lines from the active shield plate 4012 may border the field lines from the bottom left sensor plate 4110 at the bottom. If the relative geometry and positions of the surrounding components change, the field lines from the bottom left sensor plate may change as well.

By configuring the electric field around the sensor plate, each sensor plate can sense primarily in the path of its own electric field, allowing the product designer to control what is sensed. Using this technique, the location where the electric field can be placed can be controlled. For example, to sense less material (e.g., the surface) closer to the plane of the sensor plate 4103, the product designer can increase the active shielding plate distance 4104 (e.g., the amount of spacing between the sensor plate 4103 and the common ring 4105). For example, the product designer can choose to reduce the size of the sensor plate 4103 by simultaneously increasing the active shielding plate distance 4104. Implementing this design change can raise the lower boundary for the sensor plate field line and place the sensed field line along an arc that is farther from the plane of the sensor plate 4103 (deeper in the sensed surface). It can be advantageous to avoid sensing surface inconsistencies. For example, if the surface is a wall made of sheetrock, inconsistencies may exist due to air bubbles in the sheetrock, variations in surface texture, inconsistencies in paint, inconsistencies due to seams between sheets of sheetrock, or other factors. In some embodiments, it may be more preferable to have less sensitivity to surface inconsistencies such that the sensor plate reading may be further out of the plane of the sensor plate 4103 and more representative of difficult-to-see configurations that may be desired to be read.

42 is an alternative sensor plate cluster 4200 including a sensor plate 4213, an active shield plate 4202, and an active shield center 4201. The sensor plate cluster 4200 of FIG. 42 can be used in a hard-to-see configuration detector 4300 depicted in FIG. 43. The embodiment shown in FIGS. 42 and 43 can function very similarly to the configuration of FIG. 41, except that the common plate is located on the opposite side of the printed circuit board. Locating the common plate on the opposite side of the printed circuit board allows the field lines to extend deeper into the surface, and also allows the field lines to move across a wider spectrum of hard-to-see configurations. As a result, a hard-to-see configuration detector including the design of FIGS. 42 and 43 can sense deeper into the sensing surface and over a wider area compared to the configuration of FIG. 41.

43 is a side view of an embodiment of a low-vision configuration detector 4300 that can use the sensor plate cluster 4200 depicted in FIG. 42. The low-vision configuration detector 4300 is positioned on the surface 2. There is a handle 4314 by which a user can grip the device and a button 4324 that can be activated or manipulated to power on the low-vision configuration detector 4300. A light pipe 4318 can direct light from an indicator 4316 on the printed circuit board 4330 to a location where the user can see the light from the indicator 4316. The printed circuit board 4330 can include or be four layers. The top layer 4344 can include most of the circuitry of the printed circuit board 4330. The second layer 4343 of the printed circuit board 4330 can include various signal routes. The third layer can include the active shielding layer 4202. The active shielding layer 4202 may cover or encompass substantially the entire third layer of the printed circuit board 4330 to protect the sensor plate 4203 from the sensing circuitry on the top layer 4344. The sensor plate 4203 may be disposed on the fourth layer. There is also an active shielding core 4201 that resides in the center of the printed circuit board 4330 on the fourth layer.

In one embodiment, the sensor plate 4203, the active shielding center 4201, and the active shielding plate 4202 are all driven by the same signal. In other words, the sensor plate 4203, the active shielding center 4201, and the active shielding plate 4202 are each driven by a signal having the same voltage at the same time. The sensor plate 4203, the active shielding center 4201, and the active shielding plate 4202 are driven together, and therefore generate an electric field together. As a result, because the active shielding plate 4202, the sensor plate 4203, and the active shielding center 4201 are each driven by the same signal, the electric field generated is the same as the electric field that would be generated if the active shielding plate 4202, the sensor plate 4203, and the active shielding center 4201 were all electrically coupled to each other. The active shielding plate 4202, the sensor plate 4203, and the active shielding center 4201 all together form a first end of the electric field. The electric fields 4304, 4305 may all have a second end of the field at the handguard common plate 4306. In this embodiment, the fringe fields 4305 near the edge of the sensor plate cluster 4200 are driven by the active shielding layer 4202. These fringe fields 4305 may originate at the active shielding layer 4302 near the edge. In this embodiment, the fringe fields 4305 penetrate to surface 2 and then wrap around and terminate at the handguard common plate 4306. In one embodiment, the handguard common plate 4306 is driven with 0 volts. In other embodiments, the handguard common plate 4306 can be driven with a different constant or alternating voltage. These fringe fields 4305 may not penetrate deep enough to penetrate the hard-to-see feature 3. The fringe fields may vary depending only on the properties of surface 2, as these fields may only penetrate surface 2 and not deep enough to reach the hard-to-see feature. For example, if there is a mismatch on face 2, the fringe field 4305 may undergo a corresponding change. Advantageously, the sensor plate 4305 may not sense the fringe field 4305.

For many applications, the sensor plate cluster 4200 depicted in FIG. 42 can perform better than the sensor plate cluster depicted in FIG. 22. The sensor plate cluster 4200 depicted in FIG. 42 can avoid sensing surface inconsistencies and further focus the sensor plate readings on difficult-to-see features that may be further away from the plane of the sensor plate 4203. This advantageously allows the difficult-to-see feature detector 4300 to sense more accurately and more deeply.

44 is a sensor plate cluster 4413 of a low vision configuration detector according to one embodiment. The sensor plate cluster 4413 includes multiple sensor plates 4404, 4405, 4406. The sensor plates 4404, 4405, 4406 are configured to form a first end of the electric field. The common plate 4401 is configured to form a second end of the electric field. An active shielding plate 4410 is disposed between the sensor plates 4404, 4405, 4406 and the common plate 4401 and is driven with a voltage. In this embodiment of FIG. 44, the edge sensor plate 4404 has a smaller surface area than the non-edge sensor plate 4406. There is a common plate width 4412, an active shielding plate width 4411, a non-edge sensor plate width 4407, and an edge sensor plate width 4408. There is also an active shielding area plate 4403. The active shielding area plate 4403 may be on a different plane. In the illustrated embodiment, the active shielding area plate 4403 is on a different layer of the printed circuit board, so in FIG. 44, the active shielding area plate 4403 is represented by the white space of the printed circuit board.

In this embodiment shown in FIG. 44, the sensor plates 4404, 4405, 4406 are driven with a signal. The active shield plate 4410 and the active shield area plate 4403 are driven with the same signal as the sensor plates 4404, 4405, 4406. Similarly, when a sensor plate 4404, 4405, 4406 is sensed, the other sensor plates 4404, 4405, 4406 in the array are driven with the same voltage signal.

The smaller sensor area of the end sensor plate 4404 makes the end sensor plate 4404 less responsive to changes in surface 2, and the responsiveness of the end sensor plate 4404 more closely matches the responsiveness of the non-end sensor plates 4405, 4406. Furthermore, the electric field formed between the end sensor plate 4404 and the common plate 4401 will be smaller than if the surface area of the end sensor plate 4404 was the same (or closely similar) to the surface area of the non-end sensor plates 4405, 4406. In other words, the smaller surface area of the end sensor plate 4404 results in a smaller electric field that is more similar in shape (including a more similar detection depth into the surface) to the electric field between the non-end sensor plates 4405, 4406 and the common plate 4401. The electric field between the end sensor plate 4404 with its smaller surface area and the common plate 4401 will not diverge as rapidly as when the end sensor plate has the same surface area as the non-end sensor plate. The electric field between the edge sensor plate 4404 and the common plate 4401 is more similar to the electric field between the non-edge sensor plates 4405, 4406 and the common plate 4401. As previously mentioned, a more similar electric field shape translates into more predictable sensor plate readings, thereby more accurately detecting poor vision configurations.

Figure 45 is a side view of a hard-to-see configuration detector 4500 that can use the sensor plate cluster 4413 depicted in Figure 44. The hard-to-see configuration detector 4500 includes a handle 14 that a user can grasp to grip the device, and a button 24 that can be actuated to power on the hard-to-see configuration detector 4500. In Figure 45, the hard-to-see configuration detector 4500 is positioned on a surface 2.

The light pipe 8 can direct light from the indicator 6 on the printed circuit board to a location where a user can see the light from the indicator 6. The low-vision configuration detector 4500 can include a four layer printed circuit board 4510. Most of the sensing circuitry, not shown, can be located on the top layer 44 of the printed circuit board 4510. The second layer 43 of the printed circuit board 4510 can include various signal routes. The third layer of the printed circuit board 4510 includes an active shielding layer 4513. The sensor plate 4406, the common plate 4401, and the active shielding plate 4410 are located on the fourth layer.

In some embodiments, the sensor plate 4406, the active shielding plate 4410, and the active shielding layer 4513 are all driven by the same voltage signal. In other words, the sensor plate 4406, the active shielding plate 4410, and the active shielding layer 4513 are each driven by a signal having the same voltage at substantially the same time. The sensor plate 4406, the active shielding plate 4410, and the active shielding layer 4513 are driven together, and therefore generate an electric field together. As a result, because the active shielding layer 4513, the sensor plate 4406, and the active shielding plate 4410 are each driven by the same signal, the electric field generated can be the same as the electric field that can be generated if the active shielding layer 4513, the sensor plate 4406, and the active shielding plate 4410 were all electrically coupled to each other. The active shielding layer 4513, the sensor plate 4406, and the active shielding plate 4410 together all form a first end of the electric field. The electric fields 4501, 4502, 4503, 4504, and 4505 may all have a second end at the common plate 4401.

In the embodiment depicted in FIG. 45, there are five electric field lines 4501, 4502, 4503, 4504, 4505 shown. There are three electric field lines 4501, 4502, and 4503 that are sensed. In addition, there are two electric field lines 4504, 4505 that are not sensed. In the embodiment depicted in FIG. 45, it may be desirable to sense objects in the difficult-to-see configuration region 4508 and to avoid sensing surface 2.

All of the electric field lines contain a common electric field, but only the electric field portion driven by the sensor plate 4406 can be sensed. The electric fields 4504, 4505 driven by the active shield plate 4410 may not penetrate deep enough to penetrate the hard-to-see structure 3. Since these electric fields 4504, 4505 may only penetrate the surface 2 and not penetrate deep enough to reach the hard-to-see structure, the readings of the unsensed electric fields 4504, 4505 may vary depending only on the characteristics of the surface 2. For example, if there is a mismatch in the surface 2, the unsensed electric fields 4504 and 4505 may undergo a corresponding change. Advantageously, the sensor plate 4406 may not sense the unsensed electric fields 4504, 4505.

Product designers can vary the relative sizes of the various components, i.e., the sensor plate 4406, the active shield plate 4410, and the common plate 4401, to direct sensing at a desired depth. For example, if the surface 2 is relatively thin, it may be desirable to have a relatively narrow active shield plate 4410 so that only a very small portion of the electric field is not sensed. Similarly, to detect difficult-to-see configurations further away from the sensor plate 4406, or to sense through a thicker surface 2, it may be desirable to have a relatively wide active shield plate 4410 and direct the sensing field deeper. Similarly, to sense through a surface 2 with a large number of discrepancies, it may be preferable to have a wide active shield plate 4410 so that the sensed electric field senses a smaller portion of the surface 2.

It is understood that to detect the hard-to-see feature 3, the sensed electric field lines 4501, 4502, 4503 would need to pass through the surface 2 twice. This would make the readings of the sensor plate 4406 sensitive to inconsistencies in the surface 2 in the areas where these electric fields pass. Fortunately, however, the quality of the sensing can be improved by not sensing the field lines that only pass through the surface 2. As a result, the sensor plate 4406 can better locate the hard-to-see feature 3, since inconsistencies in the surface 2 may not obscure the readings. As a result, the location to be sensed and the material to be sensed can be selected.

To be effective, the active shielding plate 4410 can be positioned between the common plate 4401 and the sensor plates 4404, 4405, 4406 so that the electric field generated by the active shielding plate 4410 can actually push the sensed field lines deeper into and through the surface 2. The width of the active shielding plate 4410 can vary depending on the application. For many applications, it can be recommended that the minimum dimension of the width of the active shielding plate is about 18% of the total width, which is the sum of the width of the non-end sensor plate 4407, the width of the active shielding plate 4411, and the width of the common plate 4412. For many applications, the appropriate active shielding plate width can be wider. For example, 30% can improve performance in many applications, and 40% can be an additional improvement. Similarly, a value for the width of the active shield plate that is closer to 50% of the total width, which is the sum of the non-end sensor plate width 4407, the active shield plate width 4411, and the common plate width 4412, may be ideal for many applications.

In terms of hard dimensions, an active shielding plate with a width of 13 mm can be the minimum size, with better performance at widths of 20 mm, 25 mm, or 30 mm. One skilled in the art can determine the appropriate dimensions for a particular application.

In some embodiments, the active shield, which may be on the active shield plate 4410, is driven with the same voltage signal as the voltage signal for the sensor plate 4406. In some embodiments, the active shield is driven with a constant voltage, such as 0V. In some embodiments, the active shield is driven with a voltage signal that is a ratio of the sensor plate voltage signal, and the ratio can be greater than or less than 1, making the active shield voltage signal greater than or less than the sensor plate voltage signal. In some embodiments, the active shield is positioned between the common plate 4401 and the sensor plate 4406. If the active shield voltage signal is greater than the sensor plate voltage signal, this can have the effect of moving the sensor plate electric field deeper into the surface. Furthermore, if the active shield voltage signal is less than the sensor plate voltage signal, this can have the effect of moving the sensor plate electric field shallower into the surface. In some embodiments, the user or controller can change the magnitude of the active shield voltage level to sense at different depths. In some embodiments, the sensor plate can be read multiple times with different active shield voltage signals to ascertain images of difficult-to-see structures at various depths. Such readings can also be performed by an array of sensor plates in a linear or checkerboard array to generate images of difficult-to-see structures.

46 is a side view of a hard-to-see configuration detector 4600, similar to the hard-to-see configuration detector 4005 of FIG. 45. The difference between the hard-to-see configuration detector 4500 of FIG. 45 and the hard-to-see configuration detector 4600 of FIG. 46 is the position of the common plate 4620 relative to the sensor plate 4606 and the active shielding plate 4610. In the hard-to-see configuration detector 4600 of FIG. 46, the active shielding layer 4613 is substantially between the sensor plate 4606 and the common plate 4620. The hard-to-see configuration detector 4600 of FIG. 46 can be configured to cause the field lines (e.g., electric fields 4601, 4602, 4603, 4604, 4605) to penetrate deeper into the surface, allowing for a hard-to-see configuration detector that can sense deeper or has a smaller size. In the embodiment shown in FIG. 46, the field lines travel more than 180 degrees along an arc between the common plate 4620 and the sensor plate 4606. In one embodiment, the common plate 4620 and the sensor plate 4606 are on opposite sides of the active shield 4613. In one embodiment, the common plate 4620 and the sensor plate 4606 are on opposite sides of the printed circuit board 4610.

The low-vision configuration detector 4600 includes a handle 14 that a user can grasp to grip the device, and a button 24 that can be actuated to power on the low-vision configuration detector 4500. In FIG. 46, the low-vision configuration detector 4600 is positioned on a surface 2.

The light pipe 8 can direct light from the indicator 6 on the printed circuit board 4610 to a location where a user can see the light from the indicator 6. The low-vision configuration detector 4600 can include a four layer printed circuit board 4610. Most of the sensing circuitry, not shown, can be located on the top layer 44 of the printed circuit board 4610. The second layer 43 of the printed circuit board 4610 can include various signal routes. The third layer of the printed circuit board 4610 can include an active shielding layer 4613. The sensor plate 4606 and the active shielding plate 4610 are located on the fourth layer.

In some embodiments, the sensor plate 4606, the active shielding plate 4610, and the active shielding layer 4613 are all driven by the same voltage signal. In other words, the sensor plate 4606, the active shielding plate 4610, and the active shielding layer 4613 are each driven by a signal having the same voltage at substantially the same time. The sensor plate 4606, the active shielding plate 4610, and the active shielding layer 4613 are driven together, and therefore generate an electric field together. As a result, because the active shielding layer 4613, the sensor plate 4606, and the active shielding plate 4610 are each driven by the same signal, the electric field generated can be the same as the electric field that can be generated if the active shielding layer 4613, the sensor plate 4606, and the active shielding plate 4610 were all electrically coupled to each other. The active shielding layer 4613, the sensor plate 4606, and the active shielding plate 4410 together all form first ends of the electric fields 4601, 4602, 4603, 4604, and 4605. Each of the electric fields 4601, 4602, 4603, 4604, and 4605 may all have a second end at the handguard common plate 4620.

In the embodiment depicted in FIG. 46, five electric field lines 4601, 4602, 4603, 4604, 4605 are illustrated. There are three electric field lines 4601, 4602, 4603 that are sensed. In addition, there are two electric field lines 4604, 4605 that are not sensed. In the embodiment depicted in FIG. 46, it may be desirable to sense objects in the difficult-to-see configuration region 4608 and to avoid sensing surface 2.

All of the electric field lines 4601, 4602, 4603, 4604, 4605 contain a common electric field, but only the electric field portion driven by the sensor plate 4606 can be sensed. The electric fields 4604, 4605 driven by the active shield plate 4610 may not penetrate deep enough to penetrate the hard-to-see structure 3. Since these electric fields 4604, 4605 may only penetrate the surface 2 and not penetrate deep enough to reach the hard-to-see structure, the readings of the unsensed electric fields 4604, 4605 may vary depending only on the characteristics of the surface 2. For example, if there is a mismatch in the surface 2, the unsensed electric fields 4604 and 4605 may undergo a corresponding change. Advantageously, the sensor plate 4606 may not sense the unsensed electric fields 4604, 4605.

A product designer can vary the relative sizes of the various components, namely the sensor plate 4606, the active shield plate 4610, and the common plate 4620, to target sensing at a desired depth. For example, if the surface 2 is relatively thin, it may be desirable to have a relatively narrow active shield plate 4610 so that only a very small portion of the electric field is not sensed. Similarly, to detect difficult-to-see configurations further away from the sensor plate 4606, or to sense through a thicker surface 2, it may be desirable to have a relatively wide active shield plate 4610 and target the sensing field deeper. Similarly, to sense through a surface 2 with a large number of discrepancies, it may be preferable to have a wide active shield plate 4610 so that the sensed electric field senses a smaller portion of the surface 2. In some embodiments, the designer can select the range to be sensed by varying the size and position of the sensor plate 4606, the active shield plate 4610, and the common plate 4620.

Figure 47 shows a plate configuration for a low-vision configuration detector 4700 according to an embodiment of the present disclosure. The low-vision configuration detector 4700 includes a ground plate 4701, a lower active shielding plate 4702, an upper active shielding plate 4707, and a set of sensor plates 4703. The bottom printed circuit board layer of the sensing substrate of the low-vision configuration detector 4700 includes the ground plate 4701, the lower active shielding plate 4702, and the set of sensor plates 4703. The printed circuit board layer adjacent above the bottom printed circuit board layer includes the upper active shielding plate 4707.

The set of sensor plates 4703 comprises a plurality of individual sensor plates 4704, 4705, 4706 which may be arranged in a row. In the embodiment of FIG. 47, at least one sensor plate of the set of sensor plates 4703 may be irregular and/or asymmetric in configuration (e.g., shape). In at least the embodiment of FIG. 47, each of the at least three sensor plates has a different sensor plate shape. For example, each of the sensor plates 4704, 4705, 4706 has a complex, asymmetric polygonal shape. More specifically, the first sensor plate 4704 has a first shape that is distinct from each other sensor plate shape (and is symmetrically mirrored to the last sensor plate). Similarly, the second sensor plate 4705 has a second shape that is distinct from each of the other sensor plate shapes (and is symmetrically mirrored to the penultimate sensor plate). In the embodiment of FIG. 47, this pattern may be repeated except for a group of similarly shaped sensor plates toward the center or center of the set of sensor plates 4703. As a further example, sensor plate 4706 is the third sensor plate from the end and is defined by a shape that is different from the shape of the sensor plate at the center of set of sensor plates 4703. In the embodiment of FIG. 47, each of the four sensor plates from the end of set of sensor plates 4703 has a different shape from each of the four sensor plates, and the shape of the center plate is also different. Furthermore, each of the four sensor plates from the end of the row of sensor plates in set of sensor plates 4703 is defined by eight or more faces. Furthermore, each of sensor plates 4704, 4705, 4706 has an inverse symmetrical counterpart at both ends of set of sensor plates 4703. A sensor plate, for example sensor plate 4704, may vary in width along its length. The shape of a sensor plate, such as sensor plate 4704, may be defined by six or more straight sides. A sensor plate may be defined by eight or more straight sides. A sensor plate may be defined by a shape having at least one curved face or portion. In one embodiment, the collection of sensor plates of various shapes in the set of sensor plates 4703 may be mirrored along a central axis to form a bilateral symmetric set of sensor plates. In another embodiment, the set of sensor plates 4703 may be asymmetric.

At least one of the sensor plates of the set of sensor plates 4703 may be coupled to a common plate (e.g., ground). In an embodiment, at least one sensor plate may be coupled to two or more common plates. In some embodiments, the sensor plates 4704, 4705, 4706 may form a first end of the electric field to be sensed. In some embodiments, the ground plate 4701 may form a second end of the electric field to be sensed. In some embodiments, all of the sensor plates in the set of sensor plates 4703 may be driven simultaneously. In some embodiments, the sensor plates of the set of sensor plates 4703 may be sensed one at a time. The lower active shield plate 4702 and the upper active shield plate 4707 may be driven simultaneously with the set of sensor plates 4703 with a signal similar to the signal applied to the set of sensor plates 4703.

In the embodiment of FIG. 47, the set of sensor plates 4703 forms a first end of the electric field that is driven and sensed, and the ground plate 4701 forms a second end of the electric field that is sensed. In another embodiment, the ground plate 4701 may act as one end of the electric field and may replace the driving source, and the set of sensor plates 4703 may hold another potential (e.g., ground) to form the second end of the electric field. In another embodiment, sensing of the electric field may occur between two or more sensor plates of the set of sensor plates 4703 and in the absence of a ground (e.g., a ground plate).

Figure 48 is a plate configuration for a low-vision configuration detector 4800 according to one embodiment of the present disclosure. The low-vision configuration detector 4800 includes a ground plate 4801, a lower active shielding plate 4802, an upper active shielding plate 4807, and a set of sensor plates 4803. The bottom printed circuit board layer of the sensing substrate of the low-vision configuration detector 4800 includes the ground plate 4801, the lower active shielding plate 4802, and the set of sensor plates 4803. The printed circuit board layer adjacent above the bottom printed circuit board layer includes the upper active shielding plate 4807.

The set of sensor plates 4803 includes a plurality of twelve individual sensor plates, including sensor plates 4804, 4805, and 4806. In the embodiment of FIG. 48, each of the sensor plates 4804, 4805, and 4806 has a complex, asymmetric, and irregular polygonal shape. Furthermore, each of the sensor plates 4804, 4805, and 4806 has an inversely symmetrical counterpart at each end of the set of sensor plates 4803. In the middle portion of the set of sensor plates 4803, there are four sensor plates, each having a regular rectangular shape.

In some embodiments, all sensor plates in the set of sensor plates 4803 may be driven simultaneously. Only one sensor plate in the set of sensor plates 4803 is driven at a time. The lower active shield plate 4802 and the upper active shield plate 4807 may be driven simultaneously with the set of sensor plates 4803 with a signal similar to the signal on the set of sensor plates 4803.

In one embodiment, ground plate 4801 may not be coupled to a circuit ground, but may be electrically coupled to a drive source, a sense source, or both. In one embodiment, the sensor plates of set 4803 of sensor plates may be electrically coupled to a drive source, a sense source, or both.

49 is a board configuration for a low-vision configuration detector 4900 according to one embodiment of the present disclosure. The sensing zone 4900 includes a ground plate 4901, a lower active shield plate 4908, an upper active shield plate 4907, and a number of sensor plates 4904, 4905, 4906, 4909, 4910, 4911. The bottom printed circuit board layer of the detection board of the low-vision configuration detector includes the ground plate 4901, the lower active shield plate 4902, and the sensor plates 4904, 4905, 4906, 4909, 4910, 4911. The printed circuit board layer adjacent above the bottom printed circuit board layer includes the upper active shield plate 4907.

The second sensor plate reading includes a combination of the readings from sensor plate 4905 and the readings from sensor plate 4911. Similarly, the third sensor plate reading includes a combination of the readings from sensor plate 4906 and the readings from sensor plate 4910. In other words, the readings from sensor plate 4904 include the first sensor plate reading, the combination of the readings from sensor plates 4905, 4911 includes the second sensor plate reading, the combination of the readings from sensor plates 4906, 4911 includes the third sensor plate reading, and the readings from sensor plate 4909 includes the fourth sensor plate reading. Each of sensor plates 4904, 4905, 4906, 4909, 4910, 4911 may be driven simultaneously. Each of the four sensor plate readings may be sampled individually.

The lower active shield plate 4908 and the upper active shield plate 4907 may be driven simultaneously with the sensor plates 4904, 4905, 4906, 4909, 4910, 4911 and may be driven with signals similar to those driving the sensor plates 4904, 4905, 4906, 4909, 4910, 4911. The ground plate 4901 may form an edge of the electric field to be sensed.

<Example>
The following are some exemplary embodiments that exist within the scope of the present disclosure. In order to avoid the complexity of providing the present disclosure, all of the examples listed below are not separately and explicitly disclosed as being combinable with all of the other examples listed below and other examples described above in this specification. As long as a person skilled in the art understands that these examples listed below and the embodiments described above cannot be combined, it is believed that such examples and embodiments can be combined within the scope of the present disclosure.

Embodiment 1:
three or more sensor plates arranged linearly to form a sensor array, each of the three or more sensor plates defining a first end of a corresponding electric field and configured to obtain a sensor reading of the corresponding electric field;
a common plate forming a second end of the corresponding electric field of one or more of the three or more sensor plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure the sensor readings for the three or more sensor plates;
an indicator that switches between an inactive and an active state to indicate the location of a range of relatively high sensor readings;
A visually impaired detector comprising:
the corresponding electric field varies based on the proximity of the sensor plate to one or more surrounding objects and material properties of each of the one or more surrounding objects;
end sensor plates at the ends of the sensor array having a smaller area than non-end sensor plates not present at the ends of the sensor array;
Hard-to-see configuration detector.

Embodiment 2:
2. A low-vision configuration detector as described in embodiment 1, wherein each of the sensor plates forms an electric field with a single common plate of the one or more common plates.

Embodiment 3:
2. The low-vision configuration detector of embodiment 1, wherein the three or more sensor plates are each simultaneously driven by the same signal.

Embodiment 4:
2. A low-vision configuration detector as described in embodiment 1, wherein the end sensor plates are configured such that a corresponding electric field formed by the end sensor plates is geometrically similar to a corresponding electric field formed by an intermediate sensor plate.

Embodiment 5:
2. The low-vision configuration detector of embodiment 1, wherein the sensor array and the common plate are in a common plane parallel to a surface that obscures the configuration to be detected upon detection.

Embodiment 6:
6. The low-vision configuration detector of embodiment 5, wherein the three or more sensor plates are each simultaneously driven by the same signal.

Embodiment 7:
each of the three or more sensor plates is simultaneously driven by the same signal;
6. The low-vision configuration detector of embodiment 5, wherein the sensing circuit measures the sensor reading of one of the three or more sensor plates.

Embodiment 8:
further comprising an active shield;
2. The low-vision configuration detector of embodiment 1, wherein the three or more sensor plates and the active shield are each simultaneously driven by the same signal.

Embodiment 9:
The three or more sensor plates and the active shield are each simultaneously driven by the same signal;
2. The low-vision configuration detector of embodiment 1, wherein the sensing circuit measures the sensor readings of only one of the sensor plates.

Embodiment 10:
2. A low-vision configuration detector as described in embodiment 1, wherein the common plate comprises a set of a plurality of individual plates, each individual plate forming a second end of the corresponding electric field of a sensor plate of the three or more sensor plates.

Embodiment 11
11. The low vision configuration detector of embodiment 10, wherein each of the plurality of individual plates operates independently.

Embodiment 12
2. A low vision configuration detector as described in embodiment 1, wherein a width dimension of the end sensor plate is smaller than a width dimension of the non-end sensor plate.

Embodiment 13
2. A low vision configuration detector as described in embodiment 1, wherein a width dimension of a first end of the end sensor plate is smaller than a width dimension of a second end of the end sensor plate.

Embodiment 14
2. A low-vision configuration detector as described in embodiment 1, wherein all non-end sensor plates of the three or more sensor plates have the same dimensions.

Embodiment 15
A voltage signal is driven on the common plate;
obtaining readings on the sensor plates of the three or more sensor plates;
2. The low-vision configuration detector of embodiment 1, wherein the indication is related to a capacitance between the common plate and the sensor plate.

Embodiment 16
three or more sensor plates arranged linearly to form a sensor array, each of the sensor plates defining a first end of a corresponding electric field and configured to obtain a sensor reading of the corresponding electric field;
a common plate forming a second end of the corresponding electric field for one or more sensor plates on the three or more sensor plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure the sensor readings of the three or more sensor plates;
an indicator that switches between an inactive and an active state to indicate the location of a range of relatively high sensor readings;
A visually impaired detector comprising:
the corresponding electric field varies based on the proximity of the sensor plate to one or more surrounding objects and material properties of each of the one or more surrounding objects;
each end sensor plate at an end of the sensor array has a dimension that is different from a dimension of a non-end sensor plate that is not at the end of the sensor array;
A low vision configuration detector, wherein the dimensions of the end sensor plates are configured such that a corresponding electric field formed by each of the end sensor plates is geometrically similar to a corresponding electric field formed by an intermediate sensor plate.

Embodiment 17
acquiring sensor readings of three or more sensor plates arranged linearly in a sensor array of a low vision configuration detector arranged on a surface;
measuring the sensor readings of the three or more sensor plates with a sensing circuit;
comparing measurements of sensor readings in different ranges of the sensing field;
switching an indicator from an inactivated state to an activated state to indicate a location of an area of the sensing field having a relatively high sensor reading;
1. A method for detecting a difficult-to-see configuration behind a surface, comprising:
the end sensor plates have a smaller area than the non-end sensor plates;
A method for detecting a hard-to-see configuration behind a surface, wherein the sensor readings are obtained from a range of sensing fields formed between the three or more sensor plates and a common plate of the hard-to-see configuration detector.

Embodiment 18
three or more sensor plates arranged along a length to form a sensor array;
a common plate forming a second end of one or more corresponding electric fields of the three or more sensor plates;
an active shield plate driven by a voltage signal and positioned between the sensor plate and the common plate;
a sensing circuit coupled to the three or more sensor plates and configured to measure sensor readings for the three or more sensor plates;
and an indicator that switches between an inactive state and an active state to indicate the location of a range of relatively high sensor readings;
each of the three or more sensor plates defines a first end of the corresponding electric field and is configured to obtain the sensor reading of the corresponding electric field;
the corresponding electric field varies based on the proximity of the sensor plate to one or more surrounding objects and material properties of each of the one or more surrounding objects;
an active shield having a width dimension measured orthogonal to the length of the sensor array;
A low-vision configuration detector, wherein a width of the active shield is greater than 18% of a combined width of the common plate, the zone of active shield and the sensor plates of the three or more sensor plates.

Embodiment 19:
three or more sensor plates arranged along a length to form a sensor array;
a common plate forming a second end of one or more corresponding electric fields of the three or more sensor plates;
an active shielding plate configured to be driven by a voltage and to influence an electric field between the three or more sensor plates and the common plate;
a sensing circuit coupled to the three or more sensor plates and configured to measure sensor readings for the three or more sensor plates;
and an indicator that switches between an inactive state and an active state to indicate the location of a range of relatively high sensor readings;
each of the three or more sensor plates defines a first end of the corresponding electric field and is configured to obtain the sensor reading of the corresponding electric field;
the corresponding electric field varies based on the proximity of the sensor plate to one or more surrounding objects and material properties of each of the one or more surrounding objects;
the active shield has a width perpendicular to the length of the sensor array;
A low-vision configuration detector, wherein the width of the active shield plate is greater than 18% of the combined width of the common plate, the active shield zone and the sensor plate.

Embodiment 20:
three or more sensor plates arranged along a length to form a sensor array;
a common plate forming a second end of one or more corresponding electric fields of the three or more sensor plates;
an active shielding plate driven by a voltage, the active shielding being configured to influence an electric field between the three or more sensor plates and the common plate;
a sensing circuit coupled to the three or more sensor plates and configured to measure sensor readings of the three or more sensor plates;
and an indicator that switches between an inactive state and an active state to indicate the location of a range of relatively high sensor readings;
each of the three or more sensor plates defines a first end of the corresponding electric field and is configured to obtain the sensor reading of the corresponding electric field;
the corresponding electric field varies based on the proximity of the sensor plate to one or more surrounding objects and material properties of each of the one or more surrounding objects;
the active shield has a width perpendicular to the length of the sensor array;
A low-vision configuration detector, wherein the active shield has a width greater than 13 millimeters.

Embodiment 21
a group of three or more sensor plates arranged radially around a central point;
a common plate forming a second end of one or more corresponding electric fields of the three or more sensor plates;
one or more active shield plates driven by a voltage and positioned outside the perimeter of said group of three or more sensor plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure sensor readings of the three or more sensor plates;
A visually impaired detector comprising:
each sensor plate of the three or more sensor plates forms a first end of the corresponding electric field that varies based on a proximity of the sensor plate to one or more surrounding objects and a material property of each of the one or more surrounding objects; and obtaining the sensor reading of the corresponding electric field.
Hard-to-see configuration detector.

Embodiment 22:
22. The low-vision configuration detector of embodiment 21, wherein the common plate is a ring disposed around the one or more active shielding plates.

Embodiment 23:
22. The low-vision configuration detector of embodiment 21, wherein multiple sensor plates of the three or more sensor plates are driven simultaneously by the same signal.

Embodiment 24:
22. The low-vision configuration detector of embodiment 21, wherein a plurality of the three or more sensor plates and the one or more active shielding plates are each driven simultaneously by the same signal.

Embodiment 25:
22. A low-vision configuration detector as described in embodiment 21, wherein increasing the voltage on the one or more active shielding plates causes field lines from the sensor plates of the three or more sensor plates to take a path to the common plate that is further away from the plane of the three or more sensor plates.

Embodiment 26
22. The low-vision configuration detector of embodiment 21, wherein the one or more active shielding plates are driven by a static voltage level.

Embodiment 27
22. The low-vision configuration detector of embodiment 21, wherein the one or more active shielding plates are driven by a non-static static voltage level.

Embodiment 28:
22. The low-vision configuration detector of embodiment 21, wherein a voltage signal on the one or more active shielding plates matches a voltage signal on a sensor plate of the three or more sensor plates.

Embodiment 29:
22. The low-vision configuration detector of embodiment 21, wherein the voltage signal on the one or more active shielding plates is proportional to the voltage signals on the sensor plates of the three or more sensor plates.

Embodiment 30:
22. A low-vision configuration detector as described in embodiment 21, wherein the active shielding plate, the common plate and the three or more sensor plates are in substantially the same plane.

Embodiment 31
A voltage signal is driven on the common plate;
22. A low-vision configuration detector as described in embodiment 21, wherein readings are obtained on sensor plates of the three or more sensor plates, the readings being related to capacitance between the common plate and the sensor plates.

Embodiment 32:
a group of two or more sensor plates arranged radially around a central point;
a common plate forming a second end of the one or more corresponding electric fields;
one or more active shield plates driven by a voltage and positioned outside the perimeter of said group of two or more sensor plates;
a sensing circuit coupled to the two or more sensor plates and configured to measure sensor readings of the two or more sensor plates;
A visually impaired detector comprising:
each sensor plate of the two or more sensor plates forms a first end of the corresponding electric field that varies based on a proximity of the sensor plate to one or more surrounding objects and a material property of each of the one or more surrounding objects; and obtaining the sensor reading of the corresponding electric field.
Hard-to-see configuration detector.

Embodiment 33:
A hard-to-see-like configuration detector, the hard-to-see-like configuration detector comprising:
a common plate located at a center point of the bottom of the low vision configuration detector;
one or more active shielding plates driven by a voltage and arranged radially around the common plate;
three or more sensor plates arranged radially around the one or more active shield plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure sensor readings of the three or more sensor plates;
Equipped with
each sensor plate defines a corresponding electric field with the common plate, and obtains a sensor reading of the corresponding electric field that varies based on a proximity of the sensor plate to one or more surrounding objects and a material property of each of the one or more surrounding objects.
Hard-to-see configuration detector.

Embodiment 34:
a plurality of sensor plates arranged in a row;
34. A low-vision configuration detector as described in any preceding embodiment, wherein at each end of the row of sensor plates, the sensor plates are defined by a shape having six or more sides.

Embodiment 35:
35. A low-vision configuration detector as described in embodiment 34, wherein in the row of sensor plates, the sensor plate inwardly adjacent to any end sensor plate is defined by a shape having at least six sides.

Embodiment 36
36. A low-vision configuration detector as described in embodiment 35, wherein the next inner adjacent (or third from the end) sensor plate is defined by a shape having at least six sides.

Embodiment 37
37. A low-vision configuration detector as described in embodiment 36, wherein the next inner adjacent (or fourth from the end) sensor plate is defined by a shape having at least six sides.

Embodiment 38
38. A low-vision configuration detector according to any one of embodiments 34, 35, 36 and 37, wherein at least two inner-located sensor plates have a regular linear shape.

Embodiment 39:
38. A low-vision configuration detector according to any one of embodiments 34, 35, 36 and 37, wherein at least two inner-located sensor plates are of an irregular linear symmetric shape.

Embodiment 40:
40. A low-vision configuration detector as described in any one of embodiments 38 and 39, wherein the row of sensor detectors is symmetrical.

Embodiment 41
40. A low-vision configuration detector as described in any one of embodiments 38 and 39, wherein the rows of sensor detectors are asymmetric.

Embodiment 42:
42. A low-vision configuration detector as described in any one of embodiments 40 and 41, wherein at least one of the sensor plates is defined by a curved edge or a portion of a curved edge.

Embodiment 43:
42. A low-vision configuration detector as described in any one of embodiments 40 and 41, wherein the set of sensor plates is arranged in an array rather than in the form of a linear row.

Embodiment 44:
42. A low-vision configuration detector as described in any one of embodiments 40 and 41, wherein the first pair of sensor plates provide readings that are combined and interpreted as readings from a single sensor plate.

Embodiment 45:
45. A low-vision configuration detector as described in embodiment 44, wherein the second pair of sensor plates provide readings that are combined and interpreted as readings from a single sensor plate.

Embodiment 46
a sensor plate array including three or more sensor plates each defining a first end of a corresponding electric field and configured to obtain a sensor reading of the corresponding electric field;
one or more common plates forming second ends of the corresponding electric fields of one or more of the three or more sensor plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure the sensor readings for the three or more sensor plates;
an indicator that switches between an inactive and an active state to indicate the location of a range of relatively high sensor readings;
A visually impaired detector comprising:
the corresponding electric field varies based on the proximity of the sensor plate to one or more surrounding objects and material properties of each of the one or more surrounding objects;
The three or more sensor plates include a first sensor plate having a first shape and a second sensor plate having a second shape different from the first shape of the first sensor plate.

Embodiment 47
47. A low-vision configuration detector as described in embodiment 46, wherein at least one of the three or more sensor plates is asymmetric.

Embodiment 48:
47. A low-vision configuration detector as described in embodiment 46, wherein the sensor plates of the three or more sensor plates have five or more straight sides.

Embodiment 49:
47. A low-vision configuration detector as described in embodiment 46, wherein at least one of the three or more sensor plates varies in width along a length of the at least one of the three or more sensor plates.

Embodiment 50:
47. A low-vision configuration detector as described in embodiment 46, wherein the three or more sensor plates include at least three different sensor plate shapes.

Embodiment 51
47. A low-vision configuration detector as described in embodiment 46, wherein at least one of the three or more sensor plates is defined by six or more straight sides.

Embodiment 52
47. A low-vision configuration detector as described in embodiment 46, wherein at least one of the three or more sensor plates is defined by eight or more straight sides.

Embodiment 53:
47. A low-vision configuration detector as described in embodiment 46, wherein the sensor plate array is bilaterally symmetrical.

Embodiment 54:
47. A low-vision configuration detector as described in embodiment 46, wherein the sensor plate array is asymmetric.

Embodiment 55:
47. A low-vision configuration detector as described in embodiment 46, wherein at least one of the three or more sensor plates is coupled to two or more common plates.

Embodiment 56
47. A low-vision configuration detector as described in embodiment 46, wherein at least one of the three or more sensor plates is defined by at least one curved side.

Embodiment 57
a sensor plate array including three or more sensor plates arranged in a geometric pattern having one or more edges, each of the three or more sensor plates forming a first edge of a corresponding electric field and configured to obtain a sensor reading of the corresponding electric field;
one or more common plates forming a second end of the corresponding electric field for one or more of the three or more sensor plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure the sensor readings of the three or more sensor plates;
an indicator that switches between an inactive and an active state to indicate the location of a range of relatively high sensor readings;
A visually impaired detector comprising:
the corresponding electric field varies based on the proximity of the sensor plate to one or more surrounding objects and material properties of each of the one or more surrounding objects;
the three or more sensor plates include one or more middle plates and an end plate at each end of the geometric pattern;
A low vision configuration detector, wherein at least one of the end plates has an end shape that is different from an intermediate shape of the one or more intermediate plates.

Embodiment 58:
58. A low-vision configuration detector as described in embodiment 57, wherein the geometric pattern includes an array of sensor plates including the three or more sensor plates.

Embodiment 59:
the three or more sensor plates include one or more plates adjacent to and second from the end plate,
A low-vision configuration detector as described in embodiment 58, wherein at least one of the one or more plates second from the end has a shape second from the end that is different from the intermediate shape of the one or more intermediate sensor plates.

Embodiment 60:
60. A low vision configuration detector as described in embodiment 59, wherein the shape of the second end is different from the end shape of at least one of the end plates.

Embodiment 61
the three or more sensor plates include one or more plates that are a third from the end and adjacent to the second from the end;
A low-vision configuration detector as described in embodiment 59, wherein at least one of the third plates from the end has a third shape from the end that is different from the intermediate shape of the one or more intermediate plates.

Embodiment 62:
62. The low vision configuration detector of embodiment 61, wherein the shape of the third from the end is different from the shape of the second from the end and the end shape.

Embodiment 63:
the three or more sensor plates include one or more plates fourth from the end adjacent to one or more plates third from the end,
A low-vision configuration detector as described in embodiment 61, wherein at least one of the one or more plates fourth from the end has a fourth shape from the end that is different from the intermediate shape of the one or more intermediate plates.

Embodiment 64:
64. The low vision configuration detector of embodiment 63, wherein the fourth shape from the end is different from the third shape from the end, the second shape from the end, and the end shape.

Embodiment 65:
A low-vision configuration detector as described in embodiment 63, wherein the end shape, the second shape from the end, the third shape from the end, and the fourth shape from the end are each defined by eight or more straight sides.

It will be apparent to those skilled in the art that many changes may be made in the details of the above-described embodiments without departing from the underlying principles of the invention, and the scope of the invention should therefore be determined solely by the claims which follow.

Claims (17)

a sensor plate array including three or more sensor plates each defining a first end of a corresponding electric field and configured to obtain a sensor reading that varies based on a proximity of the sensor plate to one or more surrounding objects and a material property of each of the one or more surrounding objects;
one or more common plates forming second ends of the corresponding electric fields of one or more of the three or more sensor plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure the sensor readings for the three or more sensor plates;
an indicator that switches between an inactive and an active state to indicate the location of a range of relatively high sensor readings;
a difficult-to-see configuration detector for detecting difficult-to-see configurations located behind, under or in an opaque surface to be tested ;
the three or more sensor plates include a first sensor plate having a first shape and a second sensor plate having a second shape different from the first shape of the first sensor plate;
A low vision configuration detector, wherein the three or more sensor plates include at least three different sensor plate shapes. The low-vision configuration detector of claim 1, wherein at least one of the three or more sensor plates is asymmetric. The low-vision configuration detector of claim 1, wherein the three or more sensor plates have five or more straight sides. The low-vision configuration detector of claim 1, wherein at least one of the three or more sensor plates varies in width along a length of the at least one of the three or more sensor plates. The low-vision configuration detector of claim 1, wherein at least one of the three or more sensor plates is defined by six or more straight edges. The low-vision configuration detector of claim 1, wherein at least one of the three or more sensor plates is defined by eight or more straight sides. The low-vision detector of claim 1, wherein the sensor plate array is bilaterally symmetric. The low-vision detector of claim 1, wherein the sensor plate array is asymmetric. The low-vision configuration detector of claim 1, wherein at least one of the three or more sensor plates is coupled to two or more common plates. The low-vision configuration detector of claim 1, wherein at least one of the three or more sensor plates is defined by at least one curved edge. a sensor plate array including three or more sensor plates arranged in a geometric pattern having one or more edges, each of the three or more sensor plates defining a first edge of a corresponding electric field and configured to obtain a sensor reading that varies based on a proximity of the sensor plate to one or more surrounding objects and a material property of each of the one or more surrounding objects;
one or more common plates forming a second end of the corresponding electric field for one or more of the three or more sensor plates;
a sensing circuit coupled to the three or more sensor plates and configured to measure the sensor readings of the three or more sensor plates;
an indicator that switches between an inactive and an active state to indicate the location of a range of relatively high sensor readings;
a difficult-to-see configuration detector for detecting difficult-to-see configurations located behind, under or in an opaque surface to be tested ;
the three or more sensor plates include one or more middle plates and an end plate at each end of the geometric pattern;
at least one of the end plates has an end shape that is different from an intermediate shape of the one or more intermediate plates;
the geometric pattern includes an array of sensor plates including the three or more sensor plates;
the three or more sensor plates include one or more plates adjacent to the end plate and second from the end;
A low vision configuration detector, wherein at least one of the one or more plates penultimately has a penultimate shape that is different from the intermediate shape of the one or more intermediate plates. The low vision configuration detector of claim 11, wherein the shape of the second end is different from the shape of the end of the at least one end plate. the three or more sensor plates include one or more plates third from the end adjacent to one or more plates second from the end,
12. The low vision configuration detector of claim 11, wherein at least one of the one or more plates from a third end has a shape from a third end that is different from the intermediate shape of the one or more intermediate plates. The low vision configuration detector of claim 13, wherein the shape of the third end is different from the shape of the second end and the end shape. the three or more sensor plates include one or more plates fourth from the end adjacent to one or more plates third from the end,
14. The low vision configuration detector of claim 13, wherein at least one of the one or more plates fourth from an end has a fourth from an end shape that is different from the intermediate shape of the one or more intermediate plates. The visually impaired configuration detector of claim 15, wherein the fourth shape from the end is different from the third shape from the end, the second shape from the end, and the end shape. The low-vision configuration detector of claim 15, wherein the end shape, the second shape from the end, the third shape from the end, and the fourth shape from the end are each defined by eight or more straight sides.

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