Abstract:
Methods and systems are provided for displaying a user alert option in a vehicle having a transparent conformal display unit. In one embodiment, a method includes: receiving user input indicating a request to view an alert option; and in response to the user input, generating a conformal image that illustrates at least one of a time and a distance to a point, and selectively generating a display signal to display the conformal image on a transparent display of the vehicle through the transparent conformal display unit.

Description:
TECHNICAL FIELD 
       [0001]    The technical field generally relates to alert systems of a vehicle, and more particularly relates to alert systems of a vehicle that display information on a transparent display. 
       BACKGROUND 
       [0002]    Vehicles include alert systems that detect objects or conditions in proximity to the vehicle and alert the driver to the object or condition. The alerts are typically generated based on the location and path of the detected object relative to that of the location and path of the driver&#39;s vehicle. Forward collision alert systems, for example, use sensors to detect vehicles or other objects in front of the vehicle projected to be in their path within a potentially dangerous time (e.g., seconds away if current conditions continue) or distance. Forward collision alert systems typically generate warnings or alerts, for example, when the vehicle is following another vehicle too closely or when the vehicle is approaching too rapidly to another vehicle or object. 
         [0003]    A timing of the occurrence of the warnings may be configured by the driver. For example, the driver may be presented with one or more options. The options may be presented to the driver via spoken commands (e.g., “far”, “medium”, or “near”) and/or an abstract visual display (e.g., two vehicles separated by 3, 2, or 1 radar wave(s)). In some cases, the driver may have difficulty understanding the implications of the options in order to make a well-informed selection. In other cases, the driver may have difficulty understanding an issued warning or alert once an option has been selected. 
         [0004]    Accordingly, it is desirable to provide methods and systems that allow the driver to configure the timing in a manner that is easily understood by the driver. It is further desirable to provide methods and systems to alert or warn the driver in a manner that is easily understood by the driver. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. 
       SUMMARY 
       [0005]    Methods and systems are provided for displaying a user alert option in a vehicle having a transparent conformal display unit. In one embodiment, a method includes: receiving user input indicating a request to view an alert option; and in response to the user input, generating a conformal image that illustrates at least one of a time and a distance to a point, and selectively generating a display signal to display the conformal image on a transparent display of the vehicle through the transparent conformal display unit. 
         [0006]    In another embodiment, a system includes: a transparent conformal display unit; and a control module. The control module receives user input indicating a request to view an alert option, and in response to the user input, generates a conformal image that illustrates at least one of a time and a distance to a point, and selectively generates a display signal to display the conformal image on a transparent display of the vehicle through the transparent conformal display unit. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0007]    The exemplary embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein: 
           [0008]      FIG. 1  is a functional block diagram illustrating a vehicle that includes an alert system in accordance with various embodiments; 
           [0009]      FIGS. 2-4 ,  5 A,  5 B,  6 A,  6 B and  6 C are illustrations of an integrated display for displaying warnings or alerts in accordance with various embodiments; 
           [0010]      FIGS. 7-9  are illustrations of an integrated display for displaying options for selection in accordance with various embodiments; and 
           [0011]      FIGS. 10-14  are flowcharts illustrating methods that may be performed by the alert system in accordance with various embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. As used herein, the term module refers to any hardware, software, firmware, electronic control component, processing logic, and/or processor device, individually or in any combination, including without limitation: application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality. 
         [0013]    Referring now to  FIG. 1 , a vehicle  10  is shown to include a vehicle alert system  12  in accordance with various embodiments. Although the figures shown herein depict an example with certain arrangements of elements, additional intervening elements, devices, features, or components may be present in actual embodiments. It should also be understood that  FIG. 1  is merely illustrative and may not be drawn to any type of scale. 
         [0014]    In various embodiments, the vehicle alert system  12  communicates visual warnings and/or alerts to a driver via a transparent conformal display unit  14 . In various embodiments, the transparent conformal display unit  14  generally includes one or more projection devices  16  that project images  18  onto a transparent display such as a windshield  20  of the vehicle  10  (or other transparent surface in front of the driver). The images  18  are projected onto the transparent display such as the windshield  20  based on display signals  22  received from the vehicle alert system  12 . As can be appreciated, the transparent conformal display unit  14  may present the images  18  to the driver using projection, reflection, or any other known methods for displaying images on a transparent display and is not limited to the present example. 
         [0015]    The vehicle alert system  12  includes one or more sensors  24   a - 24   n  that sense observable conditions in proximity to the vehicle  10 . The sensors  24   a - 24   n  can be image sensors, radar sensors, ultrasonic sensors, lidar sensors, GPS-based or wireless-based vehicle-to-vehicle sensors, or other sensors that sense observable conditions in proximity to the vehicle  10 . The sensors  24   a - 24   n  sense the conditions of the vehicle  10  and generate sensor signals  26   a - 26   n  based thereon. A control module  28  receives the sensor signals  26   a - 26   n , processes the sensor signals  26   a - 26   n  to detect an object in proximity to the vehicle  10 , and selectively generates the display signals  22  for use by the transparent conformal display unit  14  to warn and/or alert the driver when an object is detected. 
         [0016]    In various embodiments, the control module  28  processes the sensor signals  26   a - 26   n  based on current vehicle conditions. In particular, the control module  28 , based on current and projected vehicle conditions, determines a level of threat to objects surrounding the vehicle. The control module  28  determines the level of threat by determining a “time-to-collision” or a “distance-to-collision” (i.e., the time or distance in which it is projected two vehicles or objects will collide) and/or a severity of the required maneuver by the driver or vehicle (e.g., hard braking) to avoid a collision. 
         [0017]    The vehicle conditions may include conditions of the vehicles (e.g., vehicle speeds, vehicle decelerations, vehicle loads, etc.) and/or ambient conditions of the vehicle (e.g., road conditions, weather conditions, etc.) either current or projected. The vehicle conditions may be received from sensors  30 , received from other control modules (not shown), determined by the control module  28 , and/or predefined within the control module  28 . Based on the determined time or distance with respect to a projected collision, the control module  28  selectively generates the display signals  22  for use by the transparent conformal display unit  14  to warn and/or alert the driver. 
         [0018]    In various embodiments, the control module  28  selectively generates the display signals  22  based on an alert timing or alert distance at which the driver desires to receive the warnings and/or alerts. As will be discussed in more detail below, the desired time or distance can be predefined and/or can be configured by a user via user settings. 
         [0019]    In various embodiments, the user settings may indicate a selected one of multiple options.  FIGS. 2-4  illustrate exemplary embodiments having three options. As can be appreciated, various other embodiments can include any number of options and are not limited to the present examples. In the exemplary embodiments, the three options include a far option, (i.e., the user wishes to receive a warning when the detected object is within a first time or distance that is considered a “far collision threat” from the vehicle), a medium option (i.e., the user wishes to receive a warning when the detected object is within a second time or distance that is considered a “medium collision threat” from the vehicle), and a near option (i.e., the user wishes to receive a warning when the detected object is within a third time or distance that is considered a “near collision threat” from the vehicle). 
         [0020]    The control module  28  generates the display signals  22  based on a comparison of the determined time or distance (given current vehicle conditions) to the time or distance defined by the selected option. The control module  28  generates the display signals  22  such that the image  18  is displayed on the windshield  20  illustrates the determined time or distance to the detected object. The control module  28  further generates the display signals  22  such that the image conforms to an environment that is viewed through the windshield  20  (referred to as a conformal image). In particular, the control module  28  calculates a position on the windshield  20  based on a determination of a driver eye, head, and/or face direction (e.g., with a face camera eye-tracker) and/or a determination of a driver eye, head, and/or face gaze location on the windshield  20  in combination with a determination of a location, size, and shape of elements in the external forward scene (e.g., roadway lane markings, roadway edges, path of roadway, 3-D trajectory of roadway, vehicles, vehicle sizes, license plates, etc.) 
         [0021]    As shown in the exemplary embodiment of  FIG. 2 , when the exemplary far option is selected, and the determined time or distance is within a range defined by the far option, the image  18   a  is displayed on a position of the windshield and having a shape and size that, when viewed by the driver, appears to be within the lane the vehicle  10  is traveling and that illustrates the determined time or distance. In this example, the distance is illustrated by three trapezoids decreasing in size based on the distance from the vehicle  10 . As can be appreciated, any other shapes, sizes, and/or number of shapes may be used to illustrate the time or distance in various embodiments. 
         [0022]    As shown in  FIG. 3 , when the medium option is selected, and the determined time or distance is within the a range defined by the medium option, the image  18   b  is displayed on a position of the windshield  20  and having a shape and size that, when viewed by the driver, appears to be within the lane the vehicle  10  is traveling and that illustrates the determined time or distance. In this example, the distance is illustrated by two trapezoids decreasing in size based on the distance from the vehicle  10 . As can be appreciated, any other shapes, sizes, and/or number of shapes may be used to illustrate the time or distance in various embodiments. 
         [0023]    As shown in  FIG. 4 , when the near option is selected, and the determined time or distance is within a range defined by the near option, the image  18   c  is displayed on a position of the windshield  20  and having a shape and size that, when viewed by the driver, appears to be within the lane the vehicle is traveling and that illustrates the determined time or distance. In this example, the distance is illustrated by one trapezoid. As can be appreciated, any other shapes, sizes, and/or number of shapes may be used to illustrate the time or distance in various embodiments. 
         [0024]    With reference back to  FIG. 1 , in various embodiments, the control module  28  may generate both warning display signals  22   a  and alert display signals  22   b  based on the selected option. For example, when the near and medium options are selected, the control module generates warning display signals  22   a  when the determined time or distance (given current vehicle conditions) is within the range defined by the options not selected (e.g., medium, or medium and far); and the control module  28  generates the alert displays signals  22   b  when the determined time or distance (given current vehicle conditions) is within the range defined by the selected option. 
         [0025]    As shown in the exemplary embodiments of  FIGS. 5A-5B , when the medium option is selected, and the determined time or distance is within the range defined by the not selected far option, a warning image  18   d  ( FIG. 5A ) is displayed that illustrates the determined time or distance. In this example, the distance is illustrated by three trapezoids, decreasing in size. Since the medium option was selected, only the trapezoids corresponding to the medium distance are highlighted. As the determined time or distance decreases and falls within the time or distance defined by the selected medium option, an alert image  18   e  ( FIG. 5B ) is displayed that illustrates the determined distance. Since the medium option was selected, each of the trapezoids is highlighted. Additionally or alternatively, a color, a size, or a shape of the trapezoids can be altered or the appearance of the shapes can flash at a rate to represent an alerting condition. 
         [0026]    As shown in the exemplary embodiments of  FIGS. 6A-6C , when the near option is selected, and the determined time or distance is within the range defined by the not selected far option, a warning image  18   f  ( FIG. 6A ) is displayed that illustrates the determined time or distance. In this case, the distance is illustrated by three trapezoids, decreasing in size. Since the near option was selected, only the trapezoids corresponding to the near distance are emphasized (e.g., highlighted, bolded, colored, etc.). As the determined time or distance decreases and falls within the range defined by the not selected medium option, another warning image  18   g  ( FIG. 6B ) is displayed that illustrates the determined time or distance. Since the near option was selected, only the trapezoids corresponding to the near time or distance are emphasized (e.g., highlighted, bolded, colored, etc.). As the determined time or distance further decreases and falls within the time or distance defined by the selected near option, an alert image  18   h  ( FIG. 6C ) is displayed that illustrates the determined time or distance. Since the near option was selected, the trapezoid is emphasized (e.g., highlighted, bolded, colored, etc.). Additionally or alternatively, a color, a size, or a shape of the trapezoid can be altered or the appearance of the shape can flash at a rate to illustrate an alert. 
         [0027]    With reference back to  FIG. 1 , as previously discussed, the user settings may be predefined (e.g., factory supplied default settings) and/or may be configured by a driver of the vehicle  10 . For example, user settings  32  may be entered by a user via a user input device  34 . In various embodiments, options for selecting the user settings  32  may be presented to the user visually via the transparent conformal display unit  14  of the vehicle  10 , and may be selected based on a user&#39;s interaction with the one or more user input devices  34  of the vehicle  10 . 
         [0028]    The control module  28  selectively generates display signals  36  to the transparent conformal display unit  14  to display the options. In the exemplary embodiments shown in  FIGS. 7-9 , the three options discussed above may be presented to the user (of course more or fewer options may be presented).  FIG. 7  illustrates the far option discussed above.  FIG. 8  illustrates the medium option discussed.  FIG. 9  illustrates the near option discussed above. Each option includes an image  18   i - 18   k  that is displayed on the windshield  20  such that the image  18   i - 18   k  conforms to an environment that is viewed through the windshield  20 . In the examples shown, the images  18   i - 18   k  are displayed on a position of the windshield  20  and having a shape and size that, when viewed by the driver, appear to be within the lane the vehicle  10  ( FIG. 1 ) is traveling. The images  18   i - 18   k  are further displayed on the windshield  20  such that they illustrate a distance or time from an object in front of the vehicle  10  ( FIG. 1 ) in which a warning or alert would be issued. As shown in the exemplary embodiment of  FIG. 7 , the image  18   i  includes three trapezoids that illustrate a distance from the vehicle  10  ( FIG. 1 ). The distance is considered a far distance from the vehicle  10  ( FIG. 1 ). When this option is selected, the control module  28  ( FIG. 1 ) sets the user settings  32  ( FIG. 1 ) to be a range of distances or times (e.g., 3 seconds time-to-collision, or other value) that is considered far from the vehicle  10  ( FIG. 1 ). 
         [0029]    As shown in the exemplary embodiments of  FIG. 8 , the image  18   j  includes two trapezoids that illustrate a distance from the vehicle  10  ( FIG. 1 ). The distance is considered a medium distance from the vehicle  10  ( FIG. 1 ). When this option is selected, the control module  28  ( FIG. 1 ) sets the user settings  32  ( FIG. 1 ) to a distance or time (e.g., 2.5 seconds time-to-collision, or other value) that is considered medium from the vehicle  10  ( FIG. 1 ). As shown in the exemplary embodiments of  FIG. 8 , the image  18   j  includes one trapezoid displayed on the windshield  20  that illustrates a distance from the vehicle  10  ( FIG. 1 ). The distance is considered a distance near the vehicle  10  ( FIG. 1 ). When this option is selected, the control module  28  ( FIG. 1 ) sets the user settings  32  to be a range of distances or times (e.g., 2 seconds time-to-collision, or other value) that is considered near the vehicle  10  ( FIG. 1 ). 
         [0030]    Referring now to  FIGS. 10-14  and with continued reference to  FIG. 1 , flowcharts illustrate methods that can be performed by the alert system  12  of  FIG. 1  to alert or warn a driver of the vehicle  10  in accordance with various embodiments. As can be appreciated in light of the disclosure, the order of operation within the method is not limited to the sequential execution as illustrated in  FIGS. 10-14 , but may be performed in one or more varying orders as applicable and in accordance with the present disclosure. 
         [0031]      FIGS. 10-13  illustrate exemplary methods for generating the alerts and/or warnings. The exemplary methods generate alerts and warnings that include both a conformal image and an image that illustrates the determined time or distance. As can be appreciated, various other embodiments can generate alerts and warnings that include a conformal image or an image that illustrates the determined time or distance and are not limited to the present examples. 
         [0032]    As can be appreciated, the methods of  FIGS. 10-13  may be scheduled to run at predetermined time intervals during operation of the vehicle  10  and/or may be scheduled to run based on predetermined events (e.g., when forward collision alert is enabled). In one example, a method may begin at  100 . The sensor signals  26   a - 26   n  are received and processed at  110 . It is determined from the processing whether an objected is detected in proximity to the vehicle  10  at  120 . If an object is not detected in proximity to the vehicle  10  at  120 , the method may end at  130 . 
         [0033]    If, however, an object is detected in proximity to the vehicle  10  at  120 , vehicle condition data  31  indicating the vehicle conditions is received and processed at  140 . The time or distance to the detected object is determined at  150  based on the vehicle conditions. The user settings  32  are retrieved at  160  and evaluated at  170 - 190 . 
         [0034]    For example, if the user settings  32  indicate that the far option was selected at  170 , the display signals  22  are generated based on the determined time or distance and the range associated with the far option at  200 . Thereafter, the method may end at  130 . If, however, the user settings  32  do not indicate that the far option was selected at  170 , rather the medium option was selected at  180 , the display signals  22  are generated based on the determined time or distance and the range associated with the medium option at  210 . Thereafter, the method may end at  130 . If, however the user settings  32  do not indicate that the far option was selected at  170  or that the medium option was selected at  180 , rather the user settings  32  indicate that the near option was selected at  190 , the display signals  22  are generated based on the determined time or distance and the range associated with the near option at  220 . Thereafter, the method may end at  130 . If, however the user settings  32  do not indicate that the far option was selected at  170  or that the medium option was selected at  180 , or that the near option was selected at  190 , the display signals  22  are generated based on the determined time or distance and the range associated with a default option (e.g., the far option) at  220 . Thereafter, the method may end at  130 . 
         [0035]      FIG. 11  illustrates an exemplary method for determining and generating display signals  22  according to the far option as described at  200  of  FIG. 10 . In one example, the method may begin at  240 . The determined time or distance is compared to the time or distance associated with the far option at  250 . If the determined time or distance is less than the time or distance associated with the far option at  250 , the conformal image that illustrates the far time or distance (e.g., image  18   a  in  FIG. 2 ) is generated and the alert display signals  22   b  are generated to alert the driver by displaying the conformal image  18   a  at  260 . Thereafter, the method may end at  270 . 
         [0036]    If, however, the determined time or distance is greater than or equal to the time or distance associated with the far option at  250 , no display signals are generated (i.e., no warnings or alerts are generated), and the method may end at  270 . 
         [0037]      FIGS. 12A and 12B  illustrate exemplary methods for determining and generating display signals  22  according to the medium option as described at  210  of  FIG. 10 .  FIG. 12A  illustrates a method  210   a  of generating alert signals  22   b . In one example, the method  210   a  may begin at  280 . The determined time or distance is compared to the time or distance associated with the medium option at  290 . If the determined time or distance is less than the time or distance associated with the medium option at  290 , the conformal image that illustrates the medium time or distance (e.g., image  18   b  in  FIG. 3 ) is generated and the alert display signals  22   b  are generated to alert the driver by displaying the conformal image  18   b  at  300 . Thereafter, the method may end at  310 . 
         [0038]    If, however, the determined time or distance is greater than or equal to the time or distance associated with the medium option at  290 , no display signals are generated (i.e., no warnings or alerts are generated), and the method may end at  310 . 
         [0039]      FIG. 12B  illustrates a method  210   b  of generating alert signals  22   b  and warning signals  22   a . In one example, the method  210   b  may begin at  320 . The determined time or distance is compared to the time or distance associated with the far option at  330 . If the determined time or distance is greater than the time or distance associated with the far option at  330 , no display signals are generated (i.e., no warnings or alerts are generated) and the method may end at  340 . If, however, the determined time or distance is less than or equal to the time or distance associated with the far option at  330 , the determined time or distance is compared to the time or distance associated with the medium option at  350 . If the determined time or distance is greater than the time or distance associated with the medium option at  350 , the conformal image that illustrates the far time or distance (e.g., image  18   d  in  FIG. 5A ) is generated and the warning display signals  22   a  are generated to warn the driver by displaying the conformal image  18   d  at  360 . Thereafter, the method may end at  340 . 
         [0040]    If, however, the determined time or distance is less than or equal to the time or distance associated with the medium option at  350 , the conformal image that illustrates the medium time or distance (e.g., image  18   e  in  FIG. 5B ) is generated and the alert display signals  22   b  are generated to alert the driver by displaying conformal image  18   e  at  370 . Additionally, the alert display signals  22   b  may cause the conformal image  18   e  to flash or to have modified colors at  370 . Thereafter, the method may end at  340 . 
         [0041]      FIGS. 13A and 13B  illustrate exemplary methods for determining and generating display signals  22  according to the near option as described at  220  of  FIG. 10 .  FIG. 13A  illustrates a method  220   a  of generating alert signals  22   b . In one example, the method  220   a  may begin at  380 . The determined time or distance is compared to the time or distance associated with the near option at  390 . If the determined time or distance is less than the time or distance associated with the near option at  390 , the conformal image that illustrates the near time or distance (e.g., image  18   c  in  FIG. 4 ) is generated and alert display signals  22   b  are generated to alert the driver by displaying the conformal image  18   c  at  400 . Thereafter, the method may end at  410 . 
         [0042]    If, however, the determined time or distance is greater than or equal to the time or distance associated with the near user settings at  390 , no display signals are generated (i.e., no warnings or alerts are generated), and the method may end at  410 . 
         [0043]      FIG. 13B  illustrates a method  220   b  of generating alert signals  22   b  and warning signals  22   a . In one example, the method  220   b  may begin at  420 . The determined time or distance is compared to the time or distance associated with the far option at  430 . If the determined time or distance is greater than the time or distance associated with the far option at  430 , no display signals are generated (i.e., no warnings or alerts are generated, and the method may end at  440 . If, however, the determined time or distance is less than or equal to the time or distance associated with the far option at  430 , the determined time or distance is compared to the time or distance associated with the medium option at  450 . If the determined time or distance is greater than the time or distance associated with the medium option at  450 , the conformal image that illustrates the far time or distance (e.g., image  18   f  in  FIG. 6A ) is generated and the warning display signals  22   a  are generated to warn the driver by displaying the conformal image  18   f  at  460 . Thereafter, the method may end at  440 . 
         [0044]    If, however, the determined time or distance is less than or equal to the time or distance associated with the medium option at  450 , the determined time or distance is compared to the time or distance associated with the near option at  470 . If the determined time or distance is greater than the time or distance associated with the near option at  470 , the conformal image that illustrates the medium time or distance (e.g., image  18   g  in  FIG. 6B ) are generated and the warning display signals  22   a  are generated to warn the driver by displaying the conformal image at  480 . Thereafter, the method may end at  440 . 
         [0045]    If, however, the determined time or distance is less than or equal to the time or distance associated with the near option at  470 , the conformal image that illustrates the near time or distance (e.g., image  18   h  in  FIG. 6C ) is generated and the alert display signals  22   b  are generated to alert the driver by displaying the conformal image  18   h  at  490 . Additionally, the alert display signals  22   b  may cause the conformal image  18   h  to flash or to have modified colors at  490 . Thereafter, the method may end at  440 . 
         [0046]      FIG. 14  illustrates an exemplary method for configuring the user settings  32  that are used to determine and generate the display signals  22 . As can be appreciated, the method of  FIG. 14  may be scheduled to run at predetermined time intervals during operation of the vehicle  10  and/or may be scheduled to run based on predetermined events. 
         [0047]    In one example, the method may begin at  500 . It is determine whether input indicating to display an option is received at  510 . If input is not received at  510 , the method may end at  520 . If however, input is received at  510 , a next option is selected at  530 . For example, the next option may begin at no option and may be incremented to one of the far option, the medium option, and the near option based on the current option (e.g., in a round-robin fashion). The option is displayed as a conformal image that illustrates the time or distance associated with the option (e.g. image  18   i ,  18   j , or  18   k  in  FIG. 7 ,  8 , or  9  respective) at  540 . If subsequent user input is received indicating that an option is selected at  550 , the user settings  32  are set based on the selected option (e.g., the far option, the medium option, and the near option) at  560  and the method may end at  520 . If, however, no user input is received indicating that an option is selected at  550 , rather the user input indicates to display a next option at  510 , the next option is selected at  530  and displayed at  540 . The options are incremented and displayed until an option is selected at  550 , and the user settings  32  are set at  560 . 
         [0048]    While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof