Patent Publication Number: US-2016240165-A1

Title: Display controller of information terminal and display control method of information terminal

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display controller of an information terminal and a display control method of an information terminal. 
     2. Description of Related Art 
     An in-vehicle information terminal such as a navigation system has various functions such as searching for a route to a destination, searching for a point of interest (POI), and playing music. In order to provide a function desired by a user, an operation screen on which an input operation is performed by the user is displayed on a display screen of the in-vehicle information terminal. 
     The operation of the in-vehicle information terminal must not have a negative effect on a vehicle driving operation, and it is also not preferable that the operation of the in-vehicle information terminal greatly inconveniences a user. Accordingly, in order to achieve suitable compatibility of the prevention of a negative effect of the operation of an application on a driving operation and convenience, an application management device has been proposed which regulates execution of an application on the basis of a vehicle condition (for example, see Japanese Patent Application Publication No. 2012-111317 (JP 2012-111317 A)). When a vehicle is in a running state, this device operates an examined application in a regulation mode in which the function thereof is partially regulated and forcibly regulates input and output of a non-examined application. 
     In the device described in JP 2012-111317 A, convenience is improved by executing the examined applications in a regulation mode in which the function thereof is partially regulated even in a state where the vehicle is running. However, since the examined applications are switched to the regulation mode without exception at the time of . transitioning to the running state, convenience may be degraded depending on the timings of operating the applications. That is, there is room for improvement in the suitable compatibility of the prevention of a negative effect of the operation of an application on a vehicle driving operation and convenience in use of the application. This problem is not limited to in-vehicle information terminals having the above-mentioned configuration but is common in mobile information terminals such as smart phones or other mobile phones used in a vehicle. 
     SUMMARY OF THE INVENTION 
     The invention provides a display controller of an information terminal and a display control method of an information terminal which can maintain convenience in use of an information terminal at a high level while preventing an operation of the information terminal from having an effect on a vehicle driving operation. 
     According to a first aspect of the invention, there is provided a display controller of an information terminal that controls a display mode of an operation screen of an information terminal used in a vehicle. The display controller of an information terminal includes: an attribute value computing unit that computes an attribute value of an operation required for completing all operations of the relevant operation components for each operation component constituting the operation screen; and a display mode control unit that changes the display made of the corresponding operation component when the computed attribute value is greater than an upper limit value allowed for the operation of the information terminal in a state where a vehicle condition transitions from a stop state. 
     According to a second aspect of the invention, there is provided a display control method of an information terminal that controls a display mode of an operation screen of an information terminal used in a vehicle. The display control method of an information terminal includes: causing a display control unit, which controls the display mode of the operation screen, to compute an attribute value of an operation required for completing all operations of the relevant operation components for each operation component constituting the operation screen; and changing the display mode of the corresponding operation component when the computed attribute value is greater than an upper limit value allowed for the operation of the information terminal in a state where a vehicle condition transitions from a stop state. 
     According to these aspects, when the attribute value computed for each operation component is greater than the allowed upper limit value, the display mode of the corresponding operation component is changed. That is, without changing the display mode without exception when the vehicle condition transitions from a stop state, the display mode of the corresponding operation component is dynamically changed each time depending on the computed attribute value. As a result, it is possible to maintain the convenience in use of the information terminal at a high level while preventing the operation of the information terminal from having an effect on a vehicle driving operation depending on the setting of the allowed upper limit value. 
     In the aspect, the attribute value computing unit may acquire a component attribute value correlated with each operation component and screen layer information indicating a link relationship between screen layers and may compute the attribute value by accumulating the component attribute values of the operation components that are operated until reaching the operation component of which the operation is completed on the basis of the screen layer information. 
     According to this configurations, since the attribute value is computed by accumulating the component attribute values of all the operated components, it is possible to obtain the attribute value corresponding to each operation step after transitioning from a stop state or while transitioning from the stop state. 
     In the aspect, the attribute value computing unit may compute the time required for completing the operations of all the operation components. According to this configuration, since the time required for completing the operation is computed in order to determine the display mode of the corresponding operation component, it is possible to weight complication of an operation, difficulty in recognition of a component, and the like depending on the time. 
     In the aspect, the component attribute value correlated with each operation component may include the time required for recognizing the corresponding operation component in the operation screen and the time required for operating the corresponding operation component. According to this configuration, the attribute value includes a recognition time for the components displayed on the screen and an operation time for operating the operation components. Accordingly, even with the same operation frequency, a screen including a large number of components and a screen having a small number of components can be weighted depending on the tithe. 
     In the aspect, the attribute value computing unit may compute the total operation frequency until all the relevant operations are completed as the attribute value for each operation component. According to this configuration, since the operation frequency required for completing all the relevant operations is computed as a completion attribute value, it is possible to reduce a computational load. 
     In the aspect, the display controller of an information terminal may further include a function limiting unit that deactivates the operation function of the operation component of which the display mode is changed by the display mode control unit. According to this configuration, since the operation function of the operation component of which the display mode is changed is deactivated, at least the operation of the corresponding operation component does not have an effect on the vehicle driving operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is a block diagram illustrating a configuration of an in-vehicle information terminal in a first embodiment of a display controller of an information terminal and a display control method of an information terminal according to the invention; 
         FIG. 2  is a diagram schematically illustrating a data structure of screen construction data stored in the in-vehicle information terminal; 
         FIG. 3  is a diagram schematically illustrating screen flow data stored in the in-vehicle information terminal; 
         FIG. 4  is a flowchart illustrating a control sequence of a display control in the in-vehicle information terminal; 
         FIG. 5A  is a diagram illustrating a display mode of a screen and illustrating a state where the display mode of a selected operation component is changed; 
         FIGS. 5B to 5D  are diagrams illustrating a display mode of a screen and illustrating a state where the display mode of a selected operation component is not changed; 
         FIG. 6  is a flowchart illustrating a control sequence of a display control in an in-vehicle information terminal in a second embodiment of a display controller and a display control method of an information terminal according to the invention; and 
         FIG. 7  is a block diagram illustrating a configuration of an in-vehicle information terminal in a, third embodiment of a display controller and a display control method of an information terminal according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     Hereinafter, a first embodiment of a display controller and a display control method of an information terminal will be described. 
     As illustrated in  FIG. 1 , an in-vehicle information terminal  11  as an information terminal in this embodiment is a. navigation system and has a function of specifying a vehicle position using a global positioning system (GPS) or the like, a function of searching for a route to a destination on the basis of the specified vehicle position and map data, and a function of searching for a point of interest (POI). 
     A vehicle on which the in-vehicle information terminal  11  is mounted is provided with a vehicle ECU  10  that acquires a vehicle condition. In this embodiment, a vehicle speed is acquired as the vehicle condition from a vehicle speed sensor disposed in the vehicle. The vehicle ECU  10  outputs the vehicle speed acquired from the vehicle speed sensor to the in-vehicle information terminal  11  via an in-vehicle network. 
     The in-vehicle information terminal  11  includes a vehicle condition determining unit  12 . The vehicle condition determining unit  12  determines in which of a stop state and a running state the vehicle condition is on the basis of the vehicle speed output from the vehicle ECU  10 . In this embodiment, it is determined that the vehicle condition is the running state when the vehicle speed is equal to or higher than a predetermined speed, and it is determined that the vehicle condition is the stop state when the vehicle speed is less than the predetermined speed. 
     The in-vehicle information terminal  11  includes an application executing unit  13  that executes an application. The application executing unit  13  executes applications on the basis of pre-installed application programs or application programs added later by a user. The application executing unit  13  controls a voice output control unit  14  disposed in the in-vehicle information terminal  11  so as to output a voice from a speaker  22  or controls a screen output control unit  15  as the display mode control unit, the function limiting unit, and the display control unit so as to display various screens on a display  21 , depending on functions or settings of the applications. 
     The display  21  is a touch panel type display and a touch position touched with a user&#39;s finger is detected by an input control unit  16  disposed in the in-vehicle information terminal  11 . The input control unit  16  outputs the detected touch position to the application executing unit  13  and the application executing unit  13  operates depending on the touch position. 
     The screen output control unit  15  reads screen construction data  31  and screen flow data  34  stored in an application data storage unit  20  on the basis of a command output from the application executing unit  13 , generates screen display data, and outputs the data to the display  21 . 
     Data structures of the screen construction data  31  and the screen flow data  34  will be described below with reference to  FIGS. 2 and 3 . As illustrated in  FIG. 2 , the screen construction data  31  includes plural component data pieces  32 . The “component” mentioned herein is a part combined into a screen and is a generic name of images such as icons, characters, illustrations, and photographs regardless of operability. The “operation component” is a component which can be operated out of the components and means a button or the like in the operation screen. 
     The component data  32  is image data itself displayed on the screen. The component data  32  is correlated with component attribute data  33 . The component attribute data  33  includes recognition time information  35 , operation time information  36 , and a task completion identifier  37  which are set for each component. 
     The recognition time information  35  is set in advance and indicates the time required for allowing a user to recognize the function or the display details of one component in each operation screen. The operation time information  36  is also set in advance and indicates the time required for selectively operating one operation component in each operation screen. 
     The task completion identifier  37  is an identifier indicating whether the corresponding component is an operation component for completing a task required for completing all operations so as to provide a function desired by a user. Here, the “task” indicates a bundle of operations which are performed on an application and includes an operation for starting an application, an operation for changing the setting of an application, and the like. For example, the task completion identifier is set to “1” when the operation component corresponds to the final component of the task, and is set to “0” when the task is not completed by selectively operating the operation component. 
     As illustrated in  FIG. 3 , the screen flow data  34  is data indicating a link relationship between screens layered with the menu screen  40  as a vertex. As described above, in this embodiment, since the in-vehicle information terminal  11  has a configuration in which a user can add an application, plural menu screens  41 ,  42  are arranged in the same layer so as to cope with an increase in application. When the in-vehicle information terminal  11  is started, the first menu screen  41  is displayed on the display  21  and the second menu screen  42  on which icons different from the first menu screen  41  are displayed is displayed depending on the user&#39;s operation. 
     As illustrated in  FIG. 1 , the in-vehicle information terminal  11  is provided with an attribute value computing unit  17  constituting the display control unit. The attribute value computing unit  17  computes the total task time Ttsk indicating the time until the task is completed after the task is started for each operation component by accumulating the recognition time information  35  and the operation time information  36  before displaying a screen. 
     A technique of computing the total task time Ttsk will be described below with reference to  FIG. 3 . It is assumed that a “music playback” application for playing a music file stored in a hard disk thereof or the like, a “VICS” application for displaying information provided through a vehicle information and communication system (VICS: registered trademark), and a “news” application added by a user so as to provide information such as news acquired from the outside are installed in the in-vehicle information terminal  11  in advance. These applications are only examples and the pre-installed applications may vary depending on the in-vehicle information terminal  11 . The number or combination of applications to be installed by a user varies depending on the in-vehicle information terminal  11 . 
     In the example illustrated in  FIG. 3 , a button serving as an entrance for executing the “music playback” application is displayed on the first menu screen  41  as a first layer. As a sequence for executing the “music playback”, an execution button  41 D of the first menu screen  41  only has to be selected. The task of “music playback” is completed by operating the execution button  41 D. As a result, a task completion screen  43  of “music playback” as a second layer is displayed and music pieces stored in the hard disk or the like is played in a predetermined order. 
     For example, when the first menu screen  41  is displayed, the attribute value computing unit  17  computes the time required for operating the execution button  41 D in the first menu screen  41  as the total task time Ttsk of “music playback”. 
     At this time, the attribute value computing unit  17  reads the component attribute data  33  correlated with the buttons  41 A to  41 F as the operation components and a title display section  41 G which are displayed on the first menu screen  41  and adds the time obtained by adding the recognition time information  35  of the buttons  41 A to  41 F and the title display section  41 G to the operation time information  36  of the execution button  41 D for selecting the “music playback”. For example, when the recognition time information  35  of the respective buttons  41 A to  41 F. is “ 0 . 5  seconds”, the recognition time of the title display section  41 G is “0.4 seconds”, and the operation time information  36  of the selection button  41 F is “0.5 seconds”, the total task time Ttsk is “0.5 sec×6+0,4 sec+0.5 sec=3.9 sec”. 
     In the example illustrated in  FIG. 3 , the button serving as an entrance for displaying or changing setting of the “VICS” application is displayed as a selection button  41 F on the first menu screen  4  L As the sequence for executing “VICS” or changing the setting thereof, the selection button  41 F on the first menu screen  41  is first selected .to display a selection screen  44  of the second layer. The selection screen  44  is a screen for selecting modes such as “only highway”, “highway/general road”, and “non-display” through the operation of the selection buttons  44 A to  44 C. By selecting one of the selection buttons  44 A to  44 C, all tasks for displaying the VICS information or changing the setting thereof are completed. When the selection buttons  44 A,  44 B of “only highway” or “highway/general road” are selected in the selection screen  44 , a screen  46  for displaying the VICS information as a third layer is output to the display  21 . 
     For example, when the first menu screen  41  is displayed, the attribute value computing unit  17  computes the time required for completing the task in the operation transitioning from the first menu screen  41  to a screen of a lower layer as the total task time Ttsk for displaying the VICS information. As described above, the task time (3.9 sec) in the first menu screen  41  is computed. The. component attribute data  33  corresponding to the selection buttons  44 A to  44 C displayed on the selection screen  44  is read and the task time in the screen is computed. For example, when the recognition time information  35  for recognizing the respective buttons  44 A to  44 C is “0.5 sec” and the operation time information  36  set for the operation of selecting one of the buttons  44 A to  44 C is “0.5 sec”, the task time in the selection screen  44  is “0.5 sec×3+0.5 sec=2 sec”. Accordingly, the total task time Ttsk of the “VICS” application based on the first menu screen  41  is a value (3.9 sec+2.0 sec=5.9 sec) obtained by adding the times required for the respective screens  41  and  44 . 
     In the example illustrated in  FIG. 3 , the “news” application is started from the second menu screen  42  as the first layer. As the sequence of starting the execution of the “news” application, a category selection button  42 E such as “information” displayed on the second menu screen  42  is first operated to transition to an information selection screen  45 . Selection buttons  45 A to  45 C for selecting fields of information displayed such as “news”, “weather”, and “traffic” and execution buttons  45 D,  45 E for selecting “vocal reading” and “no voice” are displayed on the information selection screen  45 . In the information selection screen  45 , the task is completed by selecting one of the selection buttons  45 A to  45 C and then selecting one of the execution buttons  45 D,  45 E. When the execution button  45 D of “vocal reading” is operated, a voice of reading news or the like is output from a speaker  22 . When the execution button  45 E of “no voice” is operated, no voice is output. When the execution button  45 D of “vocal reading” is operated, the task is completed at that time. However, when the execution button  45 E of “no voice” is operated, the. task is completed by selectively operating buttons  47 A,  48 A indicating “topic” on screens  47 ,  48  displayed in the next time. 
     For example, when the second menu screen  42  is displayed, the attribute value computing unit  17  computes the task time (3.9 sec) of the second menu screen  42  and the task time (for example, 3.0 sec). of the information selection screen  45  as the second layer using the same method as described above and computes the total task time 
     Ttsk by adding the task times. When there is a possibility that the task will be further branched from the screen of the second layer, the total task time Ttsk is computed for each branched task. For example, when a task that is completed by selecting the execution button  45 D and a task that is completed in the next screen  47 ,  48  by selecting the execution button  45 E are present on the information selection screen  45 , the total task times Ttsk of the tasks are computed, In this application, the total task time Ttsk for operating the execution button  45 E of “no voice” is longer than the total task time Ttsk for operating the execution button  45 D of “vocal reading”. 
     The attribute value computing unit  17  compares an operation-enabled time Topr in which the operation is allowed with the computed total task times Ttsk. The operation-enabled time Topr is the upper limit value of the time allowed for the operation of the in-vehicle information terminal  11  in a state where the vehicle condition transitions from the stop state. When the total task time Ttsk is equal to or less than the operation-enabled time Topr, the attribute value computing unit  17  outputs a command to display the operation components relevant to the task in a normal mode to the screen output control unit  15 . As a result, the buttons and the like as the operation components are displayed in an active state in which they can be operated. On the other hand, when the total task time Ttsk is greater than the operation-enabled time Topr, the attribute value computing unit  17  outputs a command to tone down and display the operation components relevant to the task in an inactive state in which they are deactivated to the screen output control unit  15 . The button in the inactive state cannot be operated and the user&#39;s operation of the application is limited. When a task in a screen of a layer lower than the screen serving as the reference is branched into plural parts as described above and only when the total task times Ttsk thereof are greater than the operation-enabled time Topr, the corresponding operation components are displayed in the inactive state. That is, when a task of which the total task time Ttsk is less than the operation-enabled time Topr is present among the plural tasks, the corresponding operation component is displayed in the active state. 
     Operations particularly relevant to a display control of the in-vehicle information terminal  11  will be described below with reference to  FIG. 4 . First, when the in-vehicle information terminal  11  is started, the attribute value computing unit  17  reads the component attribute data  33  corresponding to the components displayed on the first menu screen  41  (step S 1 ). The attribute value computing unit  17  computes the total task time Ttsk for each operation component displayed on the first menu screen  41  using the same technique as described above on the basis of the read component attribute data  33  (step S 2 ). As described above, a button as an operation component cannot be said to be correlated with one application (task). For example, when a button is used to select a category, the button may be correlated with plural applications. In this case, the attribute value computing unit  17  computes the total task times Ttsk of all the tasks correlated with the operation component. 
     The vehicle condition determining unit  12  acquires the vehicle speed output from the vehicle ECU  10  as a vehicle condition (step S 3 ), and determines whether the vehicle condition is a running state (step S 4 ). When the vehicle condition determining unit  12  determines that the vehicle is not in the running state but is in the stop state (NO in step S 4 ), the screen output control unit  15  reads the screen construction data  31  and displays the first menu screen  41  in the normal display mode on the display  21  (step S 6 ). That is, in this screen, all the operation components are displayed in a state (active state) where the selection operation is enabled. 
     On the other band, when the vehicle condition determining unit  12  determined that the vehicle condition is the running state (YES in step S 4 ), the first menu screen  41  is displayed in a mode in which the operation components of which the total task time Ttsk is greater than the operation-enabled time Topr are set to a selection-disabled state (inactive state) (step S 5 ). When the screen is displayed in this way (steps S 5 , S 6 ), the screen output control unit  15  determines whether to cause the screen to transition on the basis of the output from the input control unit  16  (step S 7 ). 
     When the screen output control unit  15  determines that the screen does not transition (NO in step S 7 ), the vehicle condition determining unit  12  acquires the vehicle condition in step S 3  again and determines whether the vehicle condition is the running state again (step S 4 ). When the stop state is continuously maintained, the screen display in which the operation components are set to the active state is maintained. When the vehicle condition transitions from the stop state to the running state, the total task time Ttsk correlated with the respective components is compared with the operation-enabled time, Topr, and an operation component of which the total task time Ttsk is greater than the operation-enabled time Topr is switched to a display in the inactive state. When the vehicle condition transitions from the running state to the stop state, a component displayed in the inactive state is switched to the active state. 
     An operation example of a component and a transition example of a screen based on such a display control will be described below in more detail. As illustrated in  FIG. 5A , when the vehicle starts running before the first menu screen  41  is displayed or while the first menu screen  41  is displayed and when the total task time Ttsk computed for the “VICS” application is greater than a predetermined operation-enabled time Topr, the selection button  41 F of “VICS” is switched to the inactive state. As a result, the starting or the setting change of the “VICS” application is limited. In addition, when an operation component of a task of which the total task time Ttsk is greater than the operation-enabled time Topr is present, the operation component is switched to the inactive state. Regarding the operation components corresponding to a task of which the total task time Ttsk is equal to or less than the operation-enabled time Topr, the buttons corresponding to the application are displayed in the active state. 
     As illustrated in  FIG. 5B , when the vehicle starts running before the first menu screen  41  is displayed or while the first menu screen  41  is displayed and, for example, when the total task time Ttsk of the “music playback” application is equal to or less than the operation-enabled time Topr, the execution button  41 D displayed in the active state. That is, the “music playback” application can be executed even after the vehicle starts running. 
     On the other hand, when the screen is operated by a user and the screen output control unit  15  determines that the screen transitions (YES in step S 1 ), the above-mentioned process is repeatedly performed on the basis of the transitioned screen again in step S 1 . 
     As illustrated in  FIG. 5C , it is assumed that the vehicle starts running, for example, when the first menu screen  41  transitions to the selection screen  44  for selecting the display mode of the VICS information or while the selection screen  44  is displayed. At this time, the total task time Ttsk with the selection screen  44  as a start point is computed before the selection screen  44  is displayed in step S 2 . When the computed total task time Ttsk (2 sec) is shorter than the total task time Ttsk (5.9 sec) computed with the first menu screen  41  as a start point and the total task time Ttsk is equal to or less than the operation-enabled time Topr, the buttons  44 A to  44 C are displayed in the active state and one thereof can be operated. That is, the “VICS” application cannot be operated when the vehicle starts running while the first menu screen  41  is displayed, but the application can be operated after transitioning to the selection screen  44 . 
     As illustrated in  FIG. 5D , it is assumed that the vehicle starts running, for example, when the second menu screen  42  transitions to the information selection screen  45  or after the second menu screen  42  transitions to the information selection screen  45 . At this time, in step S 2 , the total task time Ttsk is computed on the basis of the information selection screen  45  before the information selection screen  45  is displayed. When the total task time Ttsk of the task that is completed by operating the execution button  45 D of “vocal reading” is equal to or less than the operation-enabled time Topr, the execution button  45 D is displayed in the active state: When the execution button  45 D of “vocal reading” is operated, information is read with a voice  100 . When the execution button  45 E of “no voice” is operated and the total task time Ttsk of the task that is completed in the next screen  47 ,  48  is greater than the operation-enabled time Topr, the execution button  45 E is displayed in the inactive state. Even on a screen of a layer lower than the first layer, an operation component displayed in the active state and an operation component displayed in the inactive state are present depending on the timing of starting of the vehicle. 
     In this embodiment, since the total task time Ttsk is computed on the basis of the component attribute data  33  correlated with the corresponding operation component for each operation component in this way, it is possible to compute the total task time Ttsk even when the arrangement of the operation components is changed in the screen or between the screens by the user&#39;s operation. Since the control of the display mode is not performed on the entire screen, it is possible to allow at least the transitioning from the first menu screen  41  to the second menu screen  42 . Accordingly, even when the number of operation components displayed on the menu screen  40  increases by allowing the user to add an application, the steps of displaying an operation component of which the operation is desired by the user can be performed even at the time of running of the vehicle. 
     As described above, the following advantages are obtained in the display controller and the display control method of an information terminal according to this embodiment. (1) When the total task time Ttsk computed for each operation component is greater than the operation-enabled time Topr which is the allowable upper limit value, the display mode of the corresponding operation component is changed. That is, without changing the display mode without exception when the vehicle condition transitions from the stop state, the display mode of the corresponding operation component is dynamically changed each time depending on the computed total task time Ttsk. As a result, it is possible to maintain the convenience in use of the in-vehicle information terminal  11  at a high level while preventing the operation of the in-vehicle information terminal  11  from having an effect on the vehicle driving operation depending on the setting of the operation-enabled time Topr. 
     (2) The total task time Ttsk is computed by accumulating the values of the component attribute data  33  of all the components operated until the task is completed. Accordingly, after the vehicle transitions from the stop state or while the vehicle transitions from the stop state, the total task time Ttsk corresponding to each operation step can be obtained. 
     (3) Since the total task time Ttsk is computed as the attribute value required for completing a task, it is possible to weight complication of an operation, non-easiness in recognition of a component, and the like depending on the time. 
     (4) The total task time Ttsk includes the recognition time required for recognizing the operation components of each screen and the operation time required for operating the operation components. That is, even in the tasks having the same operation frequency until a task is completed, the recognition time or the operation time as the attribute value can be set to be long for a screen in which it is difficult to recognize the components thereof or a screen in which the operation is complicated, and the recognition time or the operation time as the attribute value can be set to be short for a screen in which it is easy to recognize the components thereof or a screen in which the operation is easy. 
     (5) Since the operation function of an operation component of which the display mode is changed to the inactive state by the screen output control unit  15  is set to be inactive, at least the operation of the corresponding operation component does not have an effect on the vehicle driving operation. 
     Second Embodiment 
     A second embodiment of a display controller and a display control method of an information terminal will be described below with a focus put on a difference from the first embodiment. The display controller according to this embodiment has the same basic configuration as the first embodiment, substantially the same elements as in the first embodiment in the drawings will be referenced by the same reference numerals and description thereof will not be repeated. 
     The component attribute data  33  in this embodiment does not include the recognition time information  35  and the operation time information  36  and includes the task completion identifier  37  and operation frequency information. The operation frequency information indicates the operation frequency of the corresponding component. For example, the operation frequency information is set to “1” for an operation component such as a selection button and is set to “0” for a component other than an operation component. The operation frequency information is configured to identify types of buttons, for example, when plural types of operation components are present in one screen such as when one of plural buttons is selected and an “enter” button is pressed. The attribute value computing unit  17  computes the total operation frequency Ntsk by accumulating the operation frequency until a task is completed on the basis of the component attribute data  33  and the screen flow data  34 . The total operation frequency Ntsk indicates the operation frequency until a task is completed. The attribute value computing unit  17  compares the total operation frequency Ntsk with an operation-enabled frequency Nopr which is the upper limit allowed for the operation of the in-vehicle information terminal  11  in a state where the vehicle condition transitions from the stop state, and displays a component of which the total operation frequency Ntsk is greater than the operation-enabled frequency Nopr in the inactive state. 
     Operations particularly relevant to the display control of the in-vehicle information terminal  11  in this embodiment will be described below with reference to FIG  6 . In this embodiment, the attribute value computing unit  17  computes the total operation frequency Ntsk for each operation component on a displayed screen on the basis of the screen flow data  34  and the component attribute data  33  (step S 21 ). 
     The vehicle condition determining unit  12  acquires the vehicle condition similarly to the first embodiment (step S 22 ) and determines whether the vehicle condition is the running state (step S 23 ). When the vehicle condition determining unit  12  determines that the vehicle is in the stop state (NO in step S 23 ), the screen output control unit  15  displays a normal screen in which all the components are displayed in the active state (step S 25 ). 
     On the other hand, when the vehicle condition determining unit  12  determines that the vehicle condition is the running state (YES in step S 23 ), the screen output control unit  15  displays a screen in which an operation component of which the total operation frequency Ntsk is greater than the operation-enabled frequency Nopr is displayed in the inactive state (step S 24 ). 
     When the screen transitions (YES in step S 26 ), the total operation frequency Ntsk is computed again before the screen is displayed in step S 21 . When the screen does not transition (NO in step S 26 ), the display mode is switched depending on the vehicle condition again in step S 22 . 
     As described above, the following advantages are obtained in the display controller and the display control method according to this embodiment. (6) When the total operation frequency Ntsk computed for each operation component is greater than the operation-enabled frequency Nopr which is the allowable upper limit value, the display mode of the corresponding operation component is changed. That is, without changing the display mode without exception when the vehicle condition transitions from the stop state, the display mode of the corresponding operation component is dynamically changed each time depending on the computed total operation frequency Ntsk. As a result, it is possible to maintain the convenience in use of the in-vehicle information terminal  11  at a high level while preventing the operation of the in-vehicle information terminal  11  from having an effect on the .vehicle driving operation depending on the setting of the operation-enabled frequency Nopr. 
     (7) The total operation. frequency Ntsk is computed by accumulating the operation frequency information included in the component attribute data  33  of all the components operated until the task is completed. Accordingly, after the vehicle transitions from the stop state or while the vehicle transitions from the stop state, the total operation frequency Ntsk corresponding to each operation step can be obtained. 
     (8) Since the total operation frequency Ntsk until all the relevant operations are completed is computed as the attribute value required for completing a task, it is possible to reduce the computational load of the in-vehicle information terminal. 
     Third Embodiment 
     A third embodiment of a display controller and a display control method of an information terminal will be described below with a focus put on a difference from the first embodiment. The display controller according to this embodiment has the same basic configuration as the first embodiment, substantially the same elements as in the first embodiment in the drawings will, be referenced by the same reference numerals and description thereof will not be repeated. 
     As illustrated in  FIG. 7 , an information terminal according to this embodiment is a portable information terminal  50  such as a smart phone carried into a vehicle. The portable information terminal  50  includes a communication module  52  that can communicate with a vehicle side. The communication module  52  acquires the vehicle condition transmitted from the vehicle ECU  10  via a vehicle-side communication unit  51  and outputs the acquired vehicle condition to the vehicle condition determining unit  12 . The portable information terminal  50  has the same configuration as the configuration for performing the display control of the in-vehicle information terminal  11  in the above-mentioned embodiments, except for the communication module  52 , a dedicated speaker  53 , and a display  54 . In this embodiment, the display  54  of the portable information terminal  50  is a touch panel type display. 
     The operations of the portable information terminal  50  are basically the same as the operations of the in-vehicle information terminal  11  in the first embodiment, but acquires the vehicle speed as the vehicle condition from the vehicle ECU  10  via the communication module  52 . 
     Therefore, similarly to the, first embodiment, the above-mentioned advantages of (1) to (5) are obtained in the display controller and the display control method according to this embodiment. 
     Other Embodiments 
     The above-mentioned embodiments may be embodied as follows. 
     In the above-mentioned embodiments, an operation component can be operated on the screen of the first layer, but the operation component can be set to the inactive state on a screen of a layer lower than the first layer. In addition, for example, when the vehicle condition is the stop state in a state where the screen of the first layer is displayed and an operation component therein is operated, the display mode of the operation component may be controlled so as to enable the operation thereof until the task is completed. 
     The total task time Ttsk is computed as the attribute value relevant to the operation until the task is completed in the first embodiment, and the total operation frequency Ntsk is computed as the attribute value in the second embodiment, but another parameter may be computed. For example, an achievement rate (%) to the total task time may be computed and compared with an upper limit value (%) thereof. 
     In the second embodiment, the component attribute data  33  includes the . operation frequency information, but the screen flow data  34  may be correlated with the operation frequency information on the respective screens. In the third embodiment, the portable information terminal  50  includes the communication module  52  for acquiring the vehicle condition. In addition, when the portable information terminal  50  includes a module capable of detecting the vehicle speed such as an acceleration sensor, the vehicle condition may be determined without communicating with the vehicle ECU  10 . 
     After the vehicle transitions from the stop state, the display mode may be set depending on the magnitude of the vehicle speed. For example, the operation-enabled time Topr and the operation-enabled frequency Nopr may be set to be smaller at the time of running at a high speed than those at the time of running at a low speed. At the time of running at a high speed, the total task time Ttsk may be set to be large by multiplying the total task time Ttsk by a coefficient varying with the vehicle speed. 
     In the above-mentioned embodiments, when a task is branched into plural parts in a screen of a layer lower than a reference screen and only when all the total task times Ttsk thereof are greater than the operation-enabled time Topr, the corresponding operation components are displayed in the inactive state. In addition, when a task of which the total task time Ttsk is greater than the operation-enabled time Topr is present among the tasks branched in the lower layer, the corresponding operation components may be set to the inactive state. 
     In the above mentioned embodiments, the total task time Ttsk is computed each time before displaying a screen, but the total task time Ttsk of a task in which the arrangement of the operation component as an entrance such as a pre-installed application is not changed may not be computed each time but the once-computed total task time Ttsk may be maintained. According to this method, it is possible to reduce the computational load of the in-vehicle information terminal  11  or the portable information terminal  50 . 
     The above-mentioned embodiments describe an example where an application is installed in the in-vehicle information terminal  11  or the portable information terminal  50 , but an application that can be operated by the in-vehicle information terminal  11  or the portable information terminal  50  may be an application stored in the server via an external network. 
     In the above-mentioned embodiments, a vehicle speed is acquired as the vehicle condition, but other information may be acquired. For example, information on an ON/OFF state or a degree of operation of an accelerator pedal or an ON/OFF state of a brake pedal or a parking brake may be acquired and it may be determined on the basis of the acquired information whether the vehicle transitions from the stop state. Alternatively, it may be determined on the basis of an engine rotation speed whether the vehicle transitions from the stop state. Alternatively, it may be determined on the basis of plural information pieces indicating the vehicle state whether the vehicle transitions from the stop state. 
     In the above-mentioned embodiments, when the total task time Ttsk or the total operation frequency Ntsk is greater than the operation-enabled time Topr or the operation-enabled frequency Nopr as the upper limit value, the corresponding operation components are set to the inactive state in which the operation of the operation components is disabled. When the total task time or the total operation frequency Ntsk is greater than the upper limit value, only the display mode of the operation component may be changed, for example, so as to tone down or flicker the operation component. 
     In the above-mentioned embodiments, the total task time Ttsk and the total operation frequency Ntsk are computed only for a task transitioning from a reference screen to a screen of a lower layer, but the total task time Ttsk and the total operation frequency Ntsk may be computed for a task transitioning to a screen of a higher layer. For example, the total task time Ttsk and the total operation frequency Ntsk of a “return” button may be computed with the transitioning from the “return” button to a button which is a task entrance as a reverse task. 
     In the above-mentioned embodiments, the information terminal having a touch panel display  21  or  54  has been used as the information terminal, but a terminal other than such a type of information terminal may be used. For example, the invention may be applied to an information terminal such a type of display in which operation components displayed on a screen are operated with a cursor key or the like.