Abstract:
A method and appertaining system for implementing the method is provided for designing hearing aids having flexible parts. Three-dimensional data is provided that is related to both a soft part and a hard part of a hearing aid component into a computer-based system. Additionally, information is entered related to material characteristics for both the soft part and the hard part of the component. A component within the hearing aid shell is placed and moved in a model generated by the system. Forces, stresses, and/or amount of deformation for parts of the component based on the location of the component and at least one of another component and the shell are calculated, and the three-dimensional data model of the shell is revised based upon the calculated degree of deformation, forces, and/or stresses.

Description:
BACKGROUND 
       [0001]    One of the fundamental criteria in the design of hearing aids is to minimize size. As the current trend in the hearing aid industry continues to make shells smaller, the size requirement implies that every tenth of a millimeter of the shell height plays an important role in the determination of its the overall size. This makes the need for accurate representation of virtual models of components in the shell during modeling very important. 
       SUMMARY 
       [0002]    The present invention provides system and method for a precise representation and handling of electronic components inside the hearing aid shell in which the physical structure of the components can be accounted for. Components inside the shell, particularily a receiver, a hybrid, etc., typically comprise the “hard part” (the component itself), and the “soft part” (e.g., some form of resin boot around the component to avoid direct contact of component with the shell) The focus thus is on the correct handling of components that consist of hard and soft parts in computerized software systems. 
       DEFINITIONS AND ABBREVIATIONS 
       [0003]    The following definitions and abbreviations are used herein.
   ear impression A 3D impression from a patient&#39;s ear. The actual physical impression is scanned by 3D scanners to create a pointcloud.   pointcloud A set of 3D coordinates. Pointcloud files that come from 3D scanners are usually in ASCII format.   work order An entry in a DWOM that contains all information relevant for modelling a shell (or shells in case of binaural order) for the specific order of the ITE hearing instrument.   3D 3-Dimensional   ASCII American Standard Code for Information Interchange. A standard for assigning numerical values to the set of letters in the Roman alphabet and typographic characters.   AutoMoDe Automatic Modeling and Detailing Software   DWOM Digital Work Order Management; DWOM is the interface between AutoMoDe and back-end/business systems like SMART. DWOM is based on Microsoft COM.   elasticity The ability of a body to resist a distorting influence or stress and to return to its original size and shape when the stress is removed. All solids are elastic for small enough deformations or strains, but if the stress exceeds a certain amount known as the elastic limit, a permanent deformation is produced. Both the resistance to stress and the elastic limit depend on the composition of the solid. Some different kinds of stresses are tension, compression, torsion, and shearing. For each kind of stress and the corresponding strain there is a modulus, i.e., the ratio of the stress to the strain; the ratio of tensile stress to strain for a given material is called its Young&#39;s modulus   ERP/CRM Enterprise Resource Planning/Customer Relationship Management   ITE Inside The Ear   N/A Not Applicable   RSM Rapid Shell Manufacturing Software   SMART The ERP/CRM system upon which SHI runs its business   SLA Stereolithography (a manufacturing method utilising laser beams &amp; liquid polymers)   SLS Selective Laser Sintering (a manufacturing method utilizing laser beams &amp; polyamide powder)   STL File format for 3D representations of objects; used as input for SLA &amp; SLS. There are two versions of STL formats: binary and ASCII.   Young&#39;s modulus Number representing (in pounds per square inch or dynes per square centimeter) the ratio of stress to strain for a wire or bar of a given substance. According to Hooke&#39;s law, the strain is proportional to stress, and therefore the ratio of the two is a constant that is commonly used to indicate the elasticity of the substance. Young&#39;s modulus is the elastic modulus for tension, or tensile stress, and is the force per unit cross section of the material divided by the fractional increase in length resulting from the stretching of a standard rod or wire of the material   UI User Interface   
 
         [0022]    The present invention provides the software implementation of representative electronic component behavior in a hearing aid instrument. This requires the modeling of flexible material behavior, representative deformation modeling, and dynamic constraints modeling. Within the context of this implementation, electronic components are modeled as comprising a hard core and a soft exterior. While the internal core remains intact during virtual and physical component placement, the exterior cover undergoes flexural motion when exposed to contact forces. In the prior art automation software systems available for hearing instrument design, these concepts are completely absent, although the general basis for correct replication of physical assemblying protocols in hearing instrument manufacturing and for process automation is known. 
         [0023]    The goal of the present invention is to mimic the behaviour of the components having soft parts in computerized 3D models to have the models behave as identical as possible to that of the real world. 
         [0024]    The handling of components with a flexible cover does not require any special user interactions, and can be seamlessly integrated into other systems that automate the hearing aid design and manufacturing. Therefore, during the positioning of the components in the system software, the physical structure of the components in real world will be accounted for in 3D model&#39;s behaviour. 
         [0025]    Accordingly, a method is provided for designing hearing aids having flexible parts, comprising entering three dimensional data related to both a soft part and a hard part of a hearing aid component into a computer-based system; entering information related to material characteristics for both the soft part and the hard part of the component; placing and moving the component within a hearing aid shell in a model generated by the system; calculating forces, stresses, and degree of deformation for parts of the component based on the location of the component and at least one of another component and the shell; and revising the three dimensional data model based upon the calculated degree of deformation. 
         [0026]    Similarly, an appertaining system is provided for designing hearing aids having flexible parts, comprising an input mechanism for entering three dimensional data related to both a soft part and a hard part of a hearing aid component; a first storage area for storing the three-dimensional data; a second storage area for storing information related to material characteristics for both the soft part and the hard part of the component; a software routine for placing and moving the component within a hearing aid shell in a model generated by the system; a software routine for calculating forces, stresses, and degree of deformation for parts of the component based on the location of the component and at least one of another component and the shell; and a software routine for revising the three dimensional data model based upon the calculated degree of deformation. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0027]    The invention is described with respect to various preferred embodiments as illustrated in the drawing figures and appertaining descriptive text below. 
           [0028]      FIG. 1  is a pictorial isometric view of a component with flexible cover; 
           [0029]      FIG. 2  is a pictorial view of the component of  FIG. 1  having a plate positioned over the flexible cover; 
           [0030]      FIG. 3  is a pictorial view of the component with plate in an initial position and no pressure; 
           [0031]      FIG. 4  is a pictorial view of the component with plate in a position in which force is starting to be applied on the flexible cover; 
           [0032]      FIG. 5  is a pictorial view of the component with plate in a position in which a further force is being applied on the flexible cover; 
           [0033]      FIG. 6  is a pictorial view of the component with plate in a position in which a high force is being applied on the flexible cover; and 
           [0034]      FIGS. 7-9  are pictorial views showing deformation of the flexible part without the plate, and correspond with  FIGS. 3 ,  4 , &amp;  6  respectively. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]      FIG. 1  illustrates a component with flexible cover  10  comprising the component itself  20  with the flexible cover  30  (represented by the hemispherical protrusions) attached to the component  20 . The illustration in  FIG. 1  is what might be viewed by a user of the system on a user interface device of the 3D modeling system, although in a preferred embodiment, color could be used to represent the various separate portions. 
         [0036]    Components with flexible covers are movable on the display and within the system model space in the same way as components without flexible covers are movable. Each component with a flexible cover  10  comprises a hard part and a soft part, where the hard part is the component itself  20  and the soft part  30  is the flexible cover. Both the hard part and the soft part can be represented by corresponding STL files. 
         [0037]    If the component with flexible cover  10  touches a shell of the hearing aid, then the component shape is adapted to match the behaviour of the flexible cover in the real world. Collision notification is not triggered for the soft part as it would be for the hard part if the hard part were to intersect with the shell or other hard part components; the soft part is not permitted to penetrate into the shell. 
         [0038]    In the case where the soft part of the component is about to penetrate the shell, the necessary deformation calculations are applied on the soft part of the component to calculate a new deformed shape of the soft part. In case several soft parts of several different components are about to penetrate each other, necessary deformation calculations are applied on the soft part of all involved components. 
         [0039]    This is achieved by the software ensuring that forces applied to each component create a zero sum together. If any of the components have a sum of all forces applied to it that differs from zero, then the software automatically repositions the component in the nearest position at which a zero sum can be achieved. This is accomplished by moving the component in the software, in a direction of the non-zero-value vector until the sum of the forces is zero. 
         [0040]    On every place where a flexible cover is about to penetrate the shell, the forces pushing e.g., a receiver from the surfaces are applied to the flexible cover to calculate the necessary modifications.  FIG. 2  provides a view of an illustrative simulation. In this Figure, a plate  40  is positioned above the component with flexible cover  10  for the purpose of simulating the calculation of flexible cover deformations. 
         [0041]    This plate  40  simulates a hearing aid shell wall (discussed below). In a real life application, there is no plate provided by the software, and the component with flexible cover  10  interacts with the 3D objects present in the design space (e.g. the shell, other components). The hard part of the component is not permitted to be deformed, but the soft part of the component is allowed to be deformed according to a known finite element analysis approach. With this approach, the soft part of the component is represented by a geometrically similar model consisting of multiple, linked, simplified representations of discrete regions—i.e., finite elements on an unstructured grid. Equations of equilibrium, in conjunction with applicable physical considerations such as compatibility and constitutive relations, are applied to each element, and a system of simultaneous equations is constructed. The system of equations is solved for unknown values using the techniques of linear algebra or nonlinear numerical schemes. Although this is an approximate method, the accuracy of this approach can be improved by refining the mesh in the model using more elements and nodes. 
         [0042]    The software provides the possibility to specify the materials from which hard and soft parts of each component are created. As a part of material specification, Young&#39;s modulus may be utilized. For example, Young&#39;s modulus for Viton is 0.8 MPa, and Young&#39;s modulus for steel 2*10 5  MPa. 
         [0043]    The know techniques utilized may be found in the following references, which are herein incorporated by reference: Kreyszig, E., Advanced Engineering Mathematics, John Wiley and Sonds, Inc., New York (1962); Lekhnitskii, S. G., Theory of Elasticity of an Anisotropic Elastic Body, Holden-Day, San Fransisco (1963); Oden, J. T., Mechanics of Elastic Structures, McGraw-Hill, New York (1968); and Przemieniecki, J. S., Theory of Matrix Structural Analysis, McGraw-Hill, New York (1968). Furthermore, analysis tools, such as the ANSYS software produced by ANSYS, Inc., or software modultes having similar functionality may be utilized. 
         [0044]      FIGS. 3-9  illustrate an actual simulation, based on an exemplary configuration, and demonstrate the software handling of the pressure applied to the flexible cover  30  of the component  20 ; the plate pressure on the component with the flexible cover  10  was simulated. The simulation assumed that the component  20  and the plate  40  were made of steel, and flexible cover  30  is made of Viton material. Corresponding Young&#39;s modulus values for the materials were accounted for during the simulation process. 
         [0045]      FIGS. 3-9  illustrate how the model behaves when the flexible cover  30  receives pressure by the shell wall. For the sake of illustration, the following reference characters will be used to illustrate X-axis direction deformation value ranges, which in this case are represented as microns (10 −6  m) of displacement from an initial position before the force was applied. 
         [0000]    
       
         
               
             
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Displacement Reference Characters 
               
             
          
           
               
                 Ref. Char. 
                 Displacement in Microns from Pre-force Initial Position 
               
               
                   
               
               
                 100 
                 −0.345 to −0.306 
               
               
                 102 
                 −0.306 to −0.268 
               
               
                 104 
                 −0.268 to −0.229 
               
               
                 106 
                 −0.229 to −0.190 
               
               
                 108 
                 −0.190 to −0.152 
               
               
                 110 
                 −0.152 to −0.113 
               
               
                 112 
                 −0.113 to −0.074 
               
               
                 114 
                 −0.074 to −0.035 
               
               
                 116 
                 −0.035 to 0.003   
               
               
                   
               
             
          
         
       
     
         [0046]      FIG. 3  illustrates the initial position of the plate  40  and flexible cover  30 . As illustrated in the Figure, there is a minimal deformation level  100  on the entire assembly  10 ,  40 . 
         [0047]      FIGS. 4-6  illustrate the effects after pressure is applied to the component  20  with the flexible cover  30  by the user moving the component with cover  10  towards the shell wall. The flexible cover is deformed according to the applied stress and elasticity of the materials from which the component  20  and flexible cover  30  are created.  FIGS. 4-6  illustrate a progression where the component with flexible cover  10  moves towards the shell wall (illustrated by the plate  40 ). The displacement regions are represented by lined regions in the Figures, and range from a low range  100  to a moderate range  104 . 
         [0048]    When the user moves the component  10  back from the shell wall  40 , the deformation of flexible cover parts  30  is gradually removed to reflect the change in the forces applied to the component with flexible cover  10 . 
         [0049]      FIGS. 7-9  illustrate the process described above, but provides a view without the shell/plate  40 . These Figures show the areas of the flexible cover material  30  where the forces were applied—this makes it possible to see how the flexible cover material  30  is deformed, as illustrated in the software. 
         [0050]    The  FIG. 7  shows the initial situation of component with flexible cover without pressure from the shell wall—a low degree of deformation  100  is present over all of the component  10 . 
         [0051]    When the pressure is applied, the flexible cover  30  is deformed in the software as shown in  FIG. 8 . Finally,  FIG. 9  illustrates the maximum amount of pressure utilized in the simulation. When the stress is decreased, then the deformation is changed accordingly to reflect the changes in the forces. Advantageously, an ultimate design configuration is possible in which some of the soft parts are deformed, as long as a predefined criteria (such as the limit of deformation or possibly force-related parameters) is met. If such a limit is exceeded, then (given this predefined criteria, such as the limits of deformation) the software can indicate a collision. This capability is not possible in systems of the prior art in which such a configuration with the soft parts would show up as a collision—therefore, this system permits designs that are not possible with the other systems. 
         [0052]    For the purposes of promoting an understanding of the principles of the invention, reference has been made to the preferred embodiments illustrated in the drawings, and specific language has been used to describe these embodiments. However, no limitation of the scope of the invention is intended by this specific language, and the invention should be construed to encompass all embodiments that would normally occur to one of ordinary skill in the art. 
         [0053]    The present invention may be described in terms of functional block components and various processing steps. Such functional blocks may be realized by any number of hardware and/or software components configured to perform the specified functions. For example, the present invention may employ various integrated circuit components, e.g., memory elements, processing elements, logic elements, look-up tables, and the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices. Similarly, where the elements of the present invention are implemented using software programming or software elements the invention may be implemented with any programming or scripting language such as C, C++, Java, assembler, or the like, with the various algorithms being implemented with any combination of data structures, objects, processes, routines or other programming elements. The invention can be implemented in a computer running any Microsoft Windows operating system, such as Windows 2000, Windows XP, Windows Vista, or the like, or any Macintosh, Unix-based, or any other operating system on a computer system ranging from a personal laptop or palmtop to mainframe servers, where applicable. Furthermore, the present invention could employ any number of conventional techniques for electronics configuration, signal processing and/or control, data processing and the like. The word mechanism is used broadly and is not limited to mechanical or physical embodiments, but can include software routines in conjunction with processors, etc. 
         [0054]    The particular implementations shown and described herein are illustrative examples of the invention and are not intended to otherwise limit the scope of the invention in any way. For the sake of brevity, conventional electronics, control systems, software development and other functional aspects of the systems (and components of the individual operating components of the systems) may not be described in detail. Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. Moreover, no item or component is essential to the practice of the invention unless the element is specifically described as “essential” or “critical”. Numerous modifications and adaptations will be readily apparent to those skilled in this art without departing from the spirit and scope of the present invention. 
         [0000]    
       
         
               
             
               
               
             
           
               
                   
               
               
                 TABLE OF REFERENCE CHARACTERS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 component with flexible cover 
               
               
                 20 
                 component 
               
               
                 30 
                 flexible cover 
               
               
                 40 
                 plate 
               
               
                 100–116 
                 deformation ranges