Patent Publication Number: US-8120479-B2

Title: Vehicular instrument device and vehicle with vehicular instrument device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a division of U.S. application Ser. No. 12/065,187, filed Aug. 8, 2008, now U.S. Pat. No. 7,932,819, which is a National Stage entry of International Application No. PCT/JP2006/317416, filed Aug. 29, 2006, the entire specifications claims and drawings of which are incorporated herewith by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a vehicular instrument device having first and second meter cluster panels, which are disposed in an instrumental panel, and to a vehicle incorporating such a vehicular instrument device. 
     The present invention is also concerned with a vehicular display device having a first liquid crystal display unit, a second liquid crystal display unit superposed on the first liquid crystal display unit, and a controller for controlling the first and second liquid crystal display units so as to display information, and to a vehicle incorporating such a vehicular display device. 
     BACKGROUND ART 
     Vehicular instrument devices, which allow a vehicle driver to visually recognize information necessary to drive the vehicle by means of two instruments disposed in the instrument panel, are disclosed in Japanese Laid-Open Patent Publication No. 2000-168400 and Japanese Laid-Open Patent Publication No. 2002-67735. 
     Specifically, in the vehicular instrument device disclosed in Japanese Laid-Open Patent Publication No. 2000-168400, one of the instruments, which displays less urgent information such as information about parking lots, etc., is positioned in a substantially central area of the instrument panel, when the driver directs his or her line of sight toward the forward direction of the vehicle, and the other instrument, which displays more urgent information such as information about vehicle speed, route guidance for the vehicle and road traffic, is positioned in an area of the instrument panel that is closer to the steering wheel than the central area thereof. 
     In the vehicular instrument device disclosed in Japanese Laid-Open Patent Publication No. 2002-67735, one of the instruments, which displays more frequently viewed information such as information about vehicle speed and engine speed, is positioned in a substantially central area of the instrument panel, when the driver directs his or her line of sight toward the forward direction of the vehicle, and the other instrument, which displays less frequently viewed information such as information about brake malfunctions and battery charging failures, is positioned in an area of the instrument panel that is viewed inside the steering wheel. 
     Another vehicular instrument device disclosed in Japanese Laid-Open Patent Publication No. 2002-225592 has an instrument and a head-up display. The instrument displays information, the importance of which does not change even when the vehicle situation changes, such as information about vehicle speed and fuel level, which is positioned in a substantially central area of the instrument panel, or in an area of the instrument panel that is viewed inside the steering wheel when the driver directs his or her line of sight in the forward direction of the vehicle. The head-up display displays information of greater importance, such as warnings for preventing vehicle collisions, in an area of the front windshield near the instrument panel. 
     While the driver is driving the vehicle, the driver directs his or her line of sight through the front windshield toward an outside area in the forward direction of the vehicle. At this time, the driver&#39;s view covers a certain angular range around the line of sight, including the front windshield and a portion of the instrument panel. 
     With the vehicular display devices disclosed in the above publications, when the driver directs his or her line of sight in the forward direction of the vehicle, for example, the display area of the instrument that displays vehicle speed, which is important and viewed quite frequently by the driver, is viewed either (1) in a substantially central area of the instrument panel located outside of the steering wheel (Japanese Laid-Open Patent Publication No. 2000-168400, Japanese Laid-Open Patent Publication No. 2002-67735, and Japanese Laid-Open Patent Publication No. 2002-225592), or (2) in an area of the instrument panel located inside the steering wheel (Japanese Laid-Open Patent Publication No. 2002-225592). 
     In order to observe the displayed vehicle speed, the driver must move his or her head vertically and horizontally about the neck, in order to move the line of sight from the exterior area toward the display area of the instrument. If the display area of the instrument is viewed in a substantially central area of the instrument panel, then since the line of sight moves a greater distance horizontally than vertically, movement of the line of sight also requires a longer period of time when moving horizontally than when moving vertically. If the display area of the instrument is viewed in the area of the instrument panel inside the steering wheel, then the driver must move his or her line of sight by a large vertical distance. 
     Japanese Laid-Open Patent Publication No. 11-352943 and Japanese Laid-Open Patent Publication No. 2000-108722 disclose vehicular display devices having a first liquid crystal display unit, and a second liquid crystal display unit superposed on the first liquid crystal display unit. The first and second liquid crystal display units display information about vehicle speed, etc., for the driver to visually recognize. 
     In the vehicular display device disclosed in Japanese Laid-Open Patent Publication No. 11-352943, the first liquid crystal display unit displays vehicle speed, while the second liquid crystal display unit superposed on the first liquid crystal display unit displays vehicle speed in a superposed relation to the vehicle speed displayed by the first liquid crystal display unit. In the vehicular display device disclosed in Japanese Laid-Open Patent Publication No. 2000-108722, the first liquid crystal display unit displays route guidance information for the driver as well as the temperature outside of the vehicle, while the second liquid crystal display unit superposed on the first liquid crystal display unit forms a speedometer, comprising an arcuate array of display segments simulating an analog pointer, for displaying vehicle speed. 
     With the above vehicular display devices, various items of information required by the driver must be displayed by a plurality of display elements, which are disposed in the first liquid crystal display unit and the second liquid crystal display unit respectively. 
     The vehicular display devices of Japanese Laid-Open Patent Publication No. 11-352943 and Japanese Laid-Open Patent Publication No. 2000-108722 simultaneously display many items of information through the display elements. For allowing the driver to visually recognize such various items of information, the liquid crystal display units must be large in size and contain many display elements. As a result, each time the various items of information are displayed, the driver needs to move his or her line of sight in order to view the displayed information. 
     SUMMARY OF INVENTION 
     It is an object of the present invention to provide a vehicular instrument device, which reduces movement of the line of sight of the driver, as well as a vehicle incorporating such a vehicular instrument device. A further object of the present invention is to provide a vehicular display device, as well as a vehicle incorporating such a vehicular display device. 
     According to an aspect of the present invention, the vehicular instrument device comprises a first meter cluster panel for displaying information that is visually recognizable within a predetermined angular field of vision outside of a steering wheel of the vehicle, when a driver of the vehicle directs a line of sight in a forward direction of the vehicle from an eye range of the driver, and a second meter cluster panel for displaying information that is visually recognizable within the predetermined angular field of vision inside the steering wheel, the first meter cluster panel and the second meter cluster panel being disposed on an instrument panel of the vehicle, wherein the first meter cluster panel is included in the instrument panel near a boundary line between the instrument panel and a front windshield of the vehicle, at a position deeper than the second meter cluster panel as viewed from the perspective of the driver, and wherein the first meter cluster panel and the second meter cluster panel have respective centers of display, the center of display of the first meter cluster panel and the center of display of the second meter cluster panel being aligned along a longitudinal direction of the vehicle. 
     With the above arrangement, since the center of display of the first meter cluster panel and the center of display of the second meter cluster panel are disposed coaxially in the longitudinal direction of the vehicle, the driver is required to move his or her line of sight only vertically. Since the first meter cluster panel is disposed near the boundary line, at a position deeper than the second meter cluster panel as viewed from the perspective of the driver, and the information displayed by the first meter cluster panel is visually recognized outside of the steering wheel, the driver directing his or her line of sight toward an exterior area outside of the vehicle in the forward direction through the front windshield finds it easy to focus on the information displayed by the first meter cluster panel. According to the present invention, the movement of the line of sight of the driver is smaller than with conventional vehicular instrument devices. The center of display of the first meter cluster panel refers to the center of a display surface of the first meter cluster panel, and the center of display of the second meter cluster panel refers to the center of a display surface of the second meter cluster panel. 
     Preferably, the vehicle has an axis passing through the center of display of the first meter cluster panel and an axis passing through the center of display of the second meter cluster panel, and the steering wheel is steerable by the driver and supported by a steering shaft having a central axis, wherein the axes of the vehicle and the central axis of the steering shaft are substantially parallel to each other when viewed from above. In particular, the vehicle has a seat on which the driver is seated, the seat having a seat center, wherein the seat center, the central axis of the steering shaft, the center of display of the first meter cluster panel and the center of display of the second meter cluster panel are aligned along a longitudinal direction of the vehicle. The driver can therefore drive the vehicle in a natural driving posture, and movement of the line of sight of the driver can further be reduced. The seat center refers to the center of the seat on which the driver is seated. 
     The first meter cluster panel and the second meter cluster panel display information of high and low visually recognized frequencies, which is classified based on the frequency at which such information is visually recognized by the driver while the driver operates the vehicle. Preferably, the first meter cluster panel displays information of high visually recognized frequency. Information of high visually recognized frequency, which is displayed by the first meter cluster panel, comprises at least vehicle speed, wherein the first meter cluster panel displays the vehicle speed digitally. The driver can thus visually recognize vehicle speed in a short period of time. 
     Preferably, the first meter cluster panel has a display surface having an upper end, which is shaped along an image of the steering wheel, as projected from the eye range onto the instrument panel. More preferably, the first meter cluster panel has a display surface having a vertical height which is smaller than the vertical height of a display surface of the second meter cluster panel. Therefore, the driver obtains a maximum field of vision with respect to the exterior area outside the vehicle. 
     According to another aspect of the present invention, a vehicular display device is provided, comprising a transmissive first liquid crystal display unit having a plurality of display elements, a transmissive second liquid crystal display unit superposed on the first liquid crystal display unit and having a plurality of display elements, and a controller for controlling the display elements of the first liquid crystal display unit and the display elements of the second liquid crystal display unit, so as to display information required by the driver, wherein the information displayed by the display elements comprises at least first information indicative of a status of the vehicle, second information for confirming an operating setting of a vehicle-mounted device, and third information for indication to the driver, wherein the controller controls the display elements to selectively display the information by selectively energizing and de-energizing the display elements, and further controls the display elements to simultaneously display the information in a non-overlapping manner. 
     With the above arrangement, the first information, and the second information or the third information, can be simultaneously displayed without overlapping each other. Even when various items of information are displayed, the line of sight of the driver is moved only a relatively small distance. 
     The first information comprises information indicative of a status of the vehicle, such as vehicle speed. The second information comprises information for confirming operational settings of a vehicle-mounted device (i.e., whether the vehicle-mounted device is in operation or not) that controls the vehicle so as to cruise while keeping a predetermined distance between the vehicle and a preceding vehicle. The third information comprises information indicating to the driver that the vehicle is approaching the preceding vehicle. 
     The display element of the first liquid crystal display unit and the display element of the second liquid crystal display unit have respective different sizes for displaying the first information. While the first information is being displayed by the display element of either one of the first liquid crystal display unit and the second liquid crystal display unit, when the second information or the third information is displayed by the display element of the other one of the first liquid crystal display unit and the second liquid crystal display unit, the controller controls the display elements so as to display the first information on the display element of the other liquid crystal display unit, wherein the display element of the other liquid crystal display unit for displaying the first information is smaller in size than the display element of the one liquid crystal display unit for displaying the first information. With this arrangement, the display elements can be arranged in the first and second liquid crystal display units, in order to display the first, second, and third information, without increasing the liquid crystal display sizes of the first liquid crystal display unit and the second liquid crystal display unit. 
     When the first information, and the second information or the third information, are simultaneously displayed by the first liquid crystal display unit and the second liquid crystal display unit, the controller preferably controls the display elements to display the information next to each other, as viewed by the driver. Thus, the movement of the line of sight of the driver can further be reduced. 
     The vehicular instrument device and the vehicular display device, as described above, can be incorporated in a vehicle. 
     Any of the vehicular instrument device, the vehicle incorporating the vehicular instrument device therein, the vehicular display device, and the vehicle incorporating the vehicular display device therein, is effective at reducing movement of the line of sight of the driver. 
     The above and other objects, features, and advantages of the present invention shall become more apparent from the following descriptions, when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front elevational view of a vehicular instrument device according to an embodiment of the present invention; 
         FIG. 2  is a side elevational view showing a layout of the vehicular instrument device shown in  FIG. 1 ; 
         FIG. 3  is a plan view showing the layout of the vehicular instrument device shown in  FIG. 1 ; 
         FIG. 4  is a table showing a relationship between items of information required by the driver and respective frequencies at which the items of information are viewed; 
         FIG. 5  is a graph showing a relationship between visual distances and visual acuity of the driver; 
         FIG. 6A  is a side elevational view of a vehicular instrument device according to a comparative example; 
         FIG. 6B  is a front elevational view of the vehicular instrument device in accordance with the comparative example; 
         FIG. 7  is a front elevational view of the vehicular instrument device, showing manners in which the line of sight of the driver moves, and the field of vision of the driver changes; 
         FIG. 8  is a front elevational view of the vehicular instrument device, showing a momentary field of vision of a driver looking in the forward direction of the vehicle; 
         FIG. 9  is a front elevational view of a vehicular display device according to an embodiment of the present invention; 
         FIG. 10A  is a front elevational view of a first liquid crystal display unit of the vehicular display device shown in  FIG. 9 ; 
         FIG. 10B  is a front elevational view of a second liquid crystal display unit of the vehicular display device shown in  FIG. 9 ; 
         FIG. 11  is a cross-sectional view taken along line XI-XI of  FIG. 9 ; 
         FIG. 12A  is a front elevational view of a display pattern, which displays vehicle speed only; 
         FIG. 12B  is a front elevational view of a display pattern, which displays information prompting the driver to brake the vehicle; and 
         FIG. 12C  is a front elevational view of a display pattern, which displays information indicating an operational state of a vehicle-mounted device (IHCC) for controlling the vehicle to cruise while keeping a predetermined distance from a preceding vehicle. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     A vehicular instrument device  10  according to an embodiment of the present invention, and a vehicle  11  incorporating the vehicular instrument device  10 , shall first be described below with reference to  FIGS. 1 through 8 . 
       FIG. 1  shows, in front elevation, the vehicular instrument device  10 , which is incorporated in the vehicle  11  according to the embodiment of the present invention.  FIG. 2  shows a side elevation of the vehicle  11 , illustrating the layout of a first meter cluster panel  16  and a second meter cluster panel  18  of the vehicular instrument device  10 .  FIG. 3  shows a plan view of the vehicle  11 , illustrating the layout of a steering wheel  12 , the first meter cluster panel  16 , and the second meter cluster panel  18 . 
     As shown in  FIGS. 1 through 3 , the first meter cluster panel  16  and the second meter cluster panel  18  are disposed in an instrument panel  14 . 
     As shown in  FIG. 1 , the first meter cluster panel  16  is an instrument for displaying various items of information digitally. The first meter cluster panel  16  includes a speedometer  22  for displaying vehicle speed of the vehicle  11 , a coolant temperature gauge  24  for displaying temperature of the coolant in the engine (not shown) of the vehicle  11 , a fuel gauge  26  for displaying the level of fuel in the fuel tank (not shown) of the vehicle  11 , and turn signal lamps  20   a ,  20   b  for displaying right and left turn signals of the vehicle  11 . The speedometer  22  is disposed at a center portion  19  (represented by a circular blank dot in  FIG. 1 ) of the display of the first meter cluster panel  16 . The fuel gauge  26  is disposed on the right side of the speedometer  22 , and the coolant temperature gauge  24  is disposed on the left side of the speedometer  22 . The turn signal lamps  20   a ,  20   b  are disposed respectively on left and right sides of the speedometer  22 . 
     The second meter cluster panel  18  comprises a tachometer  30  for displaying engine rotational speed of the vehicle  11  as analog indications, a shift indicator  32  for displaying the speed reduction ratio of the transmission (not shown) of the vehicle  11 , an odometer and trip meter  34  for displaying the mileage of the vehicle  11 , and a temperature gauge  36  for displaying the temperature outside of the vehicle  11 . The tachometer  30  is disposed at a center portion  21  (represented by a circular blank dot in  FIG. 1 ) of the display of the second meter cluster panel  18 . The odometer and trip meter  34  and the temperature gauge  36  are disposed in juxtaposed relation to each other below the tachometer  30 . The shift indicator  32  is disposed on the right side of the tachometer  30 . 
     As indicated by the circular blank dot, the center of display  19  of the first meter cluster panel  16  refers to the center of the display surface of the first meter cluster panel  16 . As indicated by the circular blank dot, the center of display  21  of the second meter cluster panel  18  refers to the center of the display surface of the second meter cluster panel  18 . The display surface of the first meter cluster panel  16  refers to a panel  17  on which the turn signal lamps  20   a ,  20   b , the speedometer  22 , the coolant temperature gauge  24 , and the fuel gauge  26  are disposed. The display surface of the second meter cluster panel  18  refers to a panel  38  on which the tachometer  30 , the shift indicator  32 , the odometer and trip meter  34 , and the temperature gauge  36  are disposed. 
     The height of the panel  17  of the first meter cluster panel  16 , as measured in the vertical direction as shown in  FIG. 1 , is smaller than the height of the panel  38  of the second meter cluster panel  18 . 
     As shown in  FIG. 2 , the first meter cluster panel  16  and the second meter cluster panel  18  are disposed below a V2 line  42  extending forwardly from a V2 point  40 . The V2 line  42  represents a line of sight of a driver  48  from the V2 point  40 , and the first meter cluster panel  16 , the second meter cluster panel  18 , and other vehicle-mounted devices are not disposed above the V2 line  42 . The V2 line  42  thus refers to a reference line along which the frontal field of vision of all drivers  48  is not affected. 
     As shown in  FIGS. 1 through 3 , when the driver  48  who is seated on a seat  46  directs his or her line of sight  49  in the forward direction (indicated by the arrow X 1 ) of the vehicle  11  from an eye range  37  of the driver, the first meter cluster panel  16  is visually recognized in an area of the instrument panel  14  outside of the steering wheel  12 . The first meter cluster panel  16  as viewed from the perspective of the driver  48  is disposed near a boundary line  45  between the instrument panel  14  and the front windshield  44  and is included within the instrument panel  14 . 
     Indications on the first meter cluster panel  16 , i.e., indications of the speedometer  22 , the fuel gauge  26 , the coolant temperature gauge  24 , and the turn signal lamps  20   a ,  20   b , can thus be visually recognized outside of the steering wheel  12 , within a predetermined and certain angular range of view of the driver  48 . 
     When the driver  48  directs his or her line of sight  49  in the forward direction (indicated by the arrow X 1 ) of the vehicle  11  from the eye range  37 , the second meter cluster panel  18  is disposed in an area of the instrument panel  14  that lies inside the steering wheel  12 . At this time, indications on the second meter cluster panel  18 , i.e., indications of the tachometer  30 , the shift indicator  32 , the odometer and trip meter  34 , and the temperature gauge  36 , can be visually recognized inside the steering wheel  12 , within a predetermined and certain angular range of view of the driver  48 . 
     The eye range  37  shown in  FIG. 2  refers to a range in which the eyes  47  of all drivers  48  who are seated on the seat  46  are positioned and are capable of visually observing an exterior area in the forward direction of the vehicle, when the line of sight  49  is directed in the forward direction of the vehicle  11 , as indicated by the arrow X 0 , through the front windshield  44 . 
     As shown in  FIG. 1 , the center of display  19  of the first meter cluster panel  16 , the center of display  21  of the second meter cluster panel  18 , and the center of the steering wheel  12  are positioned on a common vertical axis  39 . As shown in  FIG. 3 , the center of display  19  of the first meter cluster panel  16 , the center of display  21  of the second meter cluster panel  18 , the center of the steering wheel  12 , and the center of the seat  46  are positioned along a central axis  52  of the steering shaft  53 , which supports the steering wheel  12  that is turned by the driver  48 . 
     The central axis  52  extends parallel to the longitudinal direction of the vehicle  11 , as indicated by the arrows X 1 , X 2  in  FIG. 3 . Therefore, when view from above, the center of the steering wheel  12 , the center of display  19  of the first meter cluster panel  16 , the center of display  21  of the second meter cluster panel  18 , and the center of the seat  46  (seat center) are disposed on the central axis  52 , along the longitudinal direction of the vehicle  11  indicated by the arrows X 1 , X 2  in  FIG. 3 . 
     As shown in  FIG. 1 , an upper end of the panel  17  of the first meter cluster panel  16 , and a region of the instrument panel  14  near the upper end of the panel  17 , are arcuate in shape along an image of the steering wheel  12  that is projected from the eye range  37  (see  FIG. 2 ) onto the instrument panel  14 . 
       FIG. 1  is a front elevational view of the vehicular instrument device  10  as viewed by the driver  48  (see  FIG. 2 ) when the line of sight  49  is directed from the eyes  47  of the driver  48 , within the eye range  37 , in the forward direction (indicated by the arrow X 1 ) of the vehicle  11 . Therefore, the steering wheel  12 , rather than the projected image of the steering wheel  12 , is shown as being superposed on the instrument panel  14 . 
     The vehicular instrument device  10  according to the present embodiment, and the vehicle  11  incorporating the vehicular instrument device  10 , are basically constructed as described above. Advantages of the vehicular instrument device  10 , as well as those of the vehicle  11 , shall be described below with reference to  FIGS. 1 through 8 . 
     First, indications produced by the first meter cluster panel  16  and the second meter cluster panel  18 , in order to allow the driver  48  (see  FIGS. 2 and 3 ) to visually recognize required information appropriately, shall be described below with reference to  FIGS. 1 through 4 . 
     The first meter cluster panel  16  and the second meter cluster panel  18  display various items of information on the panels (display surfaces)  17 ,  38  thereof based on the frequency at which the information required by the driver  48  is visually recognized, while the driver  48  operates the vehicle  11 . 
       FIG. 4  is a table showing the relationship between various meters that display items of information required by the driver  48  while the driver  48  drives the vehicle  11 , and frequencies at which the meters are visually recognized by the driver  48 . 
     In the table shown in  FIG. 4 , meters that are visually recognized by the driver  48  include, in a descending order of their visually recognized frequencies, the speedometer  22  (visually recognized frequency: 64%) (see  FIG. 1 ), the tachometer  30  (15%), the odometer and trip meter  34  ( 10 ′ a ), the fuel gauge  26  (5%), the shift indicator  32  (AT indicator and parking indicator, 3%), the coolant temperature gauge  24  (1%), and the turn signal lamps  20   a ,  20   b  (turn indicators, 1%). 
     The items of information required by the driver include, in a descending order of their visually recognized frequencies, (1) the speed of the vehicle  11  (speedometer  22 ), (2) the rotational speed of the engine (tachometer  30 ), (3) the mileage of the vehicle  11  (odometer and trip meter  34 ), (4) the level of fuel in the fuel tank (fuel gauge  26 ), (5) the speed reduction ratio (shift indicator  32 ), (6) the coolant temperature (coolant temperature gauge  24 ), and (7) right and left turn indicators of the vehicle  11  (turn signal lamps  20   a ,  20   b ). 
     Therefore, if the items of information are assigned successively to the panel  17  of the first meter cluster panel  16  and to the panel  38  of the second meter cluster panel  18  in a descending order of their visually recognized frequencies, the items of information required by the driver  48  are appropriately displayed for the driver  48  so as to facilitate visual recognition thereof. 
     In  FIG. 1 , when the driver  48  (see  FIGS. 2 and 3 ) directs his or her line of sight  49  in the forward direction (indicated by the arrow XI) of the vehicle  11 , (1) the vehicle speed of the vehicle  11  which is of the highest visually recognized frequency is displayed by the speedometer  22  at the center of display  19  of the first meter cluster panel  16  which is disposed near the line of sight  49 , (4) the fuel level in the fuel tank is displayed on the right side of the center of display  19  by the fuel gauge  26 , (6) the coolant temperature is displayed on the left side of the center of display  19  by the coolant temperature gauge  24 , and (7) the indications of right and left turns of the vehicle  11  are displayed near the center of display  19  by the turn signal lamps  20   a ,  20   b.    
     The above items of information displayed by the first meter cluster panel  16  are displayed digitally. Therefore, the driver  48  can separately distinguish the displayed items of information in a short period of time. Since the speed of the vehicle  11 , which has the highest visually recognized frequency, is displayed at the center of display  19  of the first meter cluster panel  16 , the driver  48 , who is directing his or her line of sight  49  in the forward direction (indicated by the arrow X 1 ) of the vehicle  11 , can instantaneously observe and recognize the vehicle speed. 
     On the other hand, (2) the engine rotational speed, which has the second highest visually recognized frequency, is displayed at the center of display  21  of the second meter cluster panel  18  by the tachometer  30 , whereas (3) the mileage of the vehicle  11  is displayed below the center of display  21  by the odometer and trip meter  34 , and (5) the transmission speed reduction ratio is displayed to the right of the center of display  21  by the shift indicator  32 . 
     Since engine rotational speed, which is of the second highest visually recognized frequency, is displayed at the center of display  21  of the second meter cluster panel  18 , the driver  48  directing his or her line of sight  49  in the forward direction (indicated by the arrow X 1 ) of the vehicle  11  can visually recognize the engine rotational speed in a short period of time, by moving his or her line of sight  49  downwardly. 
     The first meter cluster panel  16  is disposed at a position that can easily be focused on by the driver  48 , as described below with reference to  FIGS. 1 through 3  and  5 . 
       FIG. 5  is a graph showing the relationship between visual distances and visual acuity of the driver  48  (see  FIGS. 2 and 3 ) who drives the vehicle  11 . If the visual distances of all drivers  48  seated on the seat  46  are 1 m or more, then such drivers  48  can appropriately visually recognize the information required to drive the vehicle  11 . 
     As shown in  FIGS. 2 and 3 , the first meter cluster panel  16 , which displays vehicle speed having the highest visually recognized frequency, is disposed in front of the second meter cluster panel  18  in the direction indicated by the arrow XI. Therefore, if the first meter cluster panel  16  is spaced 1 m or more from the eyes  47  of the driver  48 , then the driver  48  who drives the vehicle  11  can easily focus on the first meter cluster panel  16 . As a result, the driver  48  can reliably visually recognize the information of high visually recognized frequency, such as the vehicle speed. 
     The vehicular instrument device  10  according to the present embodiment enables the line of sight  49  of the driver  48  to be moved less than the vehicular instrument device  51 , according to a comparative example, as described below with reference to  FIGS. 1 through 3  and  6 A through  8 . The vehicular instrument device  51  according to the comparative example is a conventional vehicular instrument device, which is shown in  FIGS. 6A and 6B  as having instruments  54  and  57 . 
       FIG. 6A  shows, in side elevation, the manner in which the line of sight  49  moves when the driver  48  views the vehicular instrument device  51 .  FIG. 6B  shows, in front elevation, the manner in which the line of sight  49  moves when the driver  48  views the instruments  54  and  57 , as well as the changes in fields of vision  56 ,  58  when the line of sight  49  moves. 
     With the vehicular instrument device  51  according to the comparative example, as shown in  FIGS. 6A and 6B , when the line of sight  49  is directed in the forward direction (indicated by the arrow X 1 ) of the vehicle  11  from the eye range  37  of the driver  48 , the instrument  54  is viewed within the field of vision  58  inside the steering wheel  12 , whereas the instrument  57  is viewed in a central area of the instrument panel  14  outside of the steering wheel  12 . The instrument  54  has a central axis  55  that is offset from a central axis  59  of the steering wheel  12  toward the central area of the instrument panel  14 . 
     In order for the driver  48 , who is seated on the seat  46 , to see information such as vehicle speed displayed on the instruments  54 ,  57 , the driver  48  must move his or her head vertically and horizontally about the neck, in order to change the line of sight  49  from the exterior area in the forward direction (indicated by the arrow X 1 ) of the vehicle toward the instruments  54 ,  57 . 
     Specifically, as shown in  FIG. 6A , when the driver  48  moves his or her line of sight  49 , which has been directed to the exterior area through the front windshield  44 , downwardly toward the instrument  54  in order to view information, e.g., the vehicle speed, displayed on the instrument  54 , then as shown in  FIG. 6B , the field of vision of the driver  48  is reduced from the range indicated by  58  to the range indicated by  56 . As a result, the field of vision within which the driver  48  viewing the instrument  54  can see the exterior area through the front windshield  44  is reduced to a field of vision  61  near the boundary line  45 , which is defined by the dot-and-dash line representing the field of vision  56  and the solid line representing the frame of the front windshield  44 . 
     Therefore, the driver  48 , when viewing the instrument  54 , is unable to have a sufficiently large field of vision with respect to the exterior area, and hence may find it difficult to recognize, in a short period of time, persons and objects that are present in the forward direction (indicated by the arrow X 1 ) of the vehicle  11 . In this case, the driver  48  needs to move his or her line of sight  49  downwardly by a large distance, from the central area of the front windshield  44  toward the instrument  54 . Since the central axis  55  of the instrument  54  is offset from the central axis  59  of the steering wheel  12 , the driver  48  seated on the seat  46  also is forced to drive the vehicle  11  while being kept in an unnatural driving posture. 
     When the driver  48  moves his or her line of sight  49 , which has been directed at the center of display  63  of the instrument  54 , toward the instrument  57  (see  FIG. 6B ) positioned to the left of the instrument  54  in order to view the information displayed on the instrument  57 , since the line of sight  49  moves a greater distance horizontally than vertically, a longer period of time is required for the line of sight  49  to move horizontally than vertically. 
     The driver  48  is thus unable to have a proper field of vision of the exterior area, and must move his or her line of vision  49  over great distances. Further, since the instrument  57  is disposed in the central area of the instrument panel  14 , the driver  48  seated on the seat  46  is forced to drive the vehicle  11  while being kept in an unnatural driving posture. 
     When the driver  48  moves his or her line of sight  49 , which has been directed at the center of display  64  of the instrument  57 , toward an obliquely upward position on the front windshield  44  (see  FIGS. 6A and 6B ), the driver  48  can obtain a proper field of vision of the exterior area, but needs to move the line of sight  49  a great distance. 
     With the vehicular instrument device  10  according to the present embodiment, as shown in  FIGS. 1 through 3  and  7 , the center of display  19  of the first meter cluster panel  16 , the center of display  21  of the second meter cluster panel  18 , the center of the steering wheel  12 , the center of the steering shaft  53 , and the center of the seat  46  (seat center) are coaxially positioned on the axis  39  and along the central axis  52 . Consequently, when the driver  48  directs his or her line of sight  49  from the exterior area in the forward direction (indicated by the arrow X 1 ) of the vehicle  11  toward the first meter cluster panel  16 , the line of sight  49  moves only vertically. Therefore, the distance that the line of sight  49  moves is much smaller than with the vehicular instrument device  51  according to the comparative example (see  FIGS. 6A and 6B ). 
     Furthermore, the first meter cluster panel  16  that displays the speed of the vehicle  11 , and which is of the highest visually recognized frequency, is disposed near the boundary line  45  at a position deeper than that of the second meter cluster panel  18  as viewed from the eye range  37  (see  FIG. 2 ). Therefore, the vehicular instrument device  10  according to the present embodiment permits the driver  48  to focus more easily on the display surface (panel  17 ) of the first meter cluster panel  16  than with the vehicular instrument device  51  according to the comparative example. Consequently, the driver  48  can appropriately visually recognize the displayed information such as vehicle speed, etc. 
     As described above, inasmuch as the center of display  19  of the first meter cluster panel  16 , the center of display  21  of the second meter cluster panel  18 , the center of the steering wheel  12 , the center of the steering shaft  53  (see  FIG. 3 ), and the center of the seat  46  (seat center) are coaxially positioned on the axis  39  and along the central axis  52 , the driver  48  can drive the vehicle  11  while seated in a natural driving posture observing the first meter cluster panel  16  and the second meter cluster panel  18 . 
     When the driver  48  (see  FIGS. 2 and 3 ) directs his or her line of sight  49  toward the center of display  19  of the first meter cluster panel  16 , a field of vision  66 , in which the driver  48  can see the exterior area through the front windshield  44 , and lying inside the field of vision  56 , i.e., a range defined by the dot-and-dash line representing the field of vision  56  and the solid line representing the boundary line  45 , as shown in  FIG. 7 , is established. The established field of vision  66  is wider than the field of vision  61  in which the driver  48  (see  FIG. 6A ) sees the exterior area when directing his or her line of sight  49  toward the instrument  54  of the vehicular instrument device  51  according to the comparative example, i.e., a range defined by the dot-and-dash line representing the field of vision  56  and the solid line representing the boundary line  45 , as shown in  FIG. 6B . 
     Therefore, as shown in  FIG. 8 , the vehicular instrument device  10  according to the present embodiment allows the driver  48  to appropriately visually recognize activities in the exterior area as well as indications on the first meter cluster panel  16 , within a field of vision  60  (momentary field of vision) in which the driver  48  can momentarily judge activities in the exterior area in fields of vision  56 ,  58 , while also generally recognizing the indications on the second meter cluster panel  18  within the field of vision  56 . The driver  48  can thus instantaneously recognize objects, e.g., pedestrians  62 , that are present in the forward direction (indicated by the arrow X 1  in  FIGS. 2 and 3 ) while viewing the exterior area as well as the first meter cluster panel  16 , and thus can quickly control the vehicle  11  in view of the presence of pedestrians  62 . 
     The upper end of the panel  17  of the first meter cluster panel  16  is arcuate in shape along an image of the steering wheel  12  that is projected onto the instrument panel  14  when the driver  48  directs his or her line of sight  49  in the forward direction (indicated by the arrow X 1 ) from the eye range  37  (see  FIG. 2 ). The height of the panel  17  of the first meter cluster panel  16 , as measured in the vertical direction in  FIG. 1 , is smaller than the height of the panel  38  of the second meter cluster panel  18 . 
     Therefore, the driver  48  obtains a maximum field of vision with respect to the exterior area near the boundary line  45  of the front windshield  44 . 
     With the vehicular instrument device  10  according to the present embodiment, and the vehicle  11  incorporating the vehicular instrument device  10 , as described above, the line of sight of the driver  48  moves only vertically because the center of display  19  of the first meter cluster panel  16  and the center of display  21  of the second meter cluster panel  18  are disposed substantially coaxially with each other. Since the first meter cluster panel  16  is disposed at a position that is deeper than that of the second meter cluster panel  18  near the boundary line  45 , and the indications on the first meter cluster panel  16  are visually recognized outside of the steering wheel  12 , the driver  48  who directs his or her line of sight  49  toward the exterior area in the forward direction (indicated by the arrow X 1 ) through the front windshield  44  can also easily focus on the display surface (panel  17 ) of the first meter cluster panel  16 . Therefore, the vehicular instrument device  10  and the vehicle  11  according to the present embodiment enable the line of sight  49  of the driver  48  to be moved a smaller distance than in the case of the vehicular instrument device  51  according to the comparative example. 
     Next, a vehicular display device  114  according to an embodiment of the present invention, as well as a vehicle  110  incorporating the vehicular display device  114 , shall be described below with reference to  FIGS. 9 through 12C . 
       FIG. 9  shows, in front elevation, the vehicular display device  114  (also referred to as “first meter cluster panel  114 ”) incorporated in the vehicle  110  according to the present embodiment.  FIGS. 10A and 10B  show, in front elevation, the display surfaces of a first liquid crystal display unit  118   a  and a second liquid crystal display unit  118   b , respectively, of the first meter cluster panel  114 .  FIG. 11  is a cross-sectional view of the first meter cluster panel  114  shown in  FIG. 9 , taken along line XI-XI of  FIG. 9 .  FIGS. 12A through 12C  show, in front elevation, display patterns on the first meter cluster panel  114 . 
     As shown in  FIG. 9 , the first meter cluster panel  114  is disposed on an upper portion of an instrument panel  112  and outside of the steering wheel  143  as viewed by the driver of the vehicle  110  (not shown). As shown in  FIGS. 10A through 11 , the first meter cluster panel  114  comprises a planar first liquid crystal display unit  118   a , and a planar second liquid crystal display unit  118   b  that is superposed on the first liquid crystal display unit  118   a.    
     The first liquid crystal display unit  118   a  is disposed closer to the driver, and comprises, as shown in  FIG. 10A , a display element  116  positioned centrally in the first liquid crystal display unit  118   a , and a display element  120  disposed on the left side of the display element  116 . The display element  116  displays the speed of the vehicle  110 . The display element  120  displays information for indicating to the driver of the vehicle  110  that the vehicle  110  is approaching a preceding vehicle, which is driven in front of the vehicle  110 . 
     Specifically, the vehicle  110  incorporates therein a vehicle-mounted device (hereinafter referred to as an “IHCC (Intelligent Highway Cruise Control) system” for controlling the vehicle  110  to cruise, while maintaining a predetermined distance between the vehicle  110  and the preceding vehicle. The IHCC system detects, using radar, the actual vehicle-to-vehicle distance between the vehicle  110  and the preceding vehicle, and outputs various items of information, indicating that the vehicle  110  is approaching the preceding vehicle, to the first meter cluster panel  114  when the detected actual vehicle-to-vehicle distance is shorter than a vehicle-to-vehicle distance preset in the IHCC system. 
     In  FIG. 10A , the display element  120  displays a message “BRAKE” for prompting the driver to brake the vehicle  110  when the vehicle  110  approaches too closely to the preceding vehicle. 
     As shown in  FIG. 10B , the second liquid crystal display unit  118   b  comprises a display element  122  disposed in a right side area of the display surface of the second liquid crystal display unit  118   b , a display element  124  disposed to the left of the display element  122 , and display elements  126 ,  128  disposed to the left of the display element  124 . 
     The display element  122  displays vehicle speed, and the display element  124  displays information concerning whether the IHCC system in operation has detected the preceding vehicle or not. The display element  126  displays (1) information of whether the IHCC system is in operation, (2) information of whether the vehicle  110  is approaching a preceding vehicle, and (3) information of whether a radar transmitting/receiving unit is dirty or smeared and thus is incapable of detecting the preceding vehicle. The display element  128  displays a preset vehicle speed when the IHCC system is in operation. 
     Each of the display elements  116  and  120  through  128  comprises a transmissive liquid crystal display element for displaying digital information. The display elements  116 ,  122 , the display element  126 , and the display element  128  for displaying preset vehicle speed, comprise segmented liquid crystal display elements. 
     If each of the display elements  116  and  120  through  128  comprises a TN liquid crystal display element, when a controller  142  (see  FIG. 11 ) energizes LEDs  134 ,  136  to emit light, while also energizing the display elements  116  and  120  through  128 , light emitted from the LEDs  134 ,  136  is blocked by the display elements  116  and  120  through  128 . As a result, the driver observing the first meter cluster panel  114  is unable to visually recognize indications on the display elements  116  and  120  through  128 . 
     When the controller  142  energizes LEDs  134 ,  136  to emit light, while de-energizing the display elements  116  and  120  through  128 , light emitted from the LEDs  134 ,  136  is transmitted through the display elements  116  and  120  through  128  and is radiated outwardly. Therefore, the driver observing the first meter cluster panel  114  is able to visually recognize indications on the display elements  116  and  120  through  128 . 
     In the first meter cluster panel  114 , the speed of the vehicle  110  is displayed as first information indicative of a status of the vehicle  110  by the display elements  116 ,  122 . The information (1), the information (3), and the preset vehicle speed are displayed as second information for confirming operational settings of the IHCC system by the display elements  126 ,  128 . Information indicating that the vehicle  110  is approaching a preceding vehicle, information indicating that the IHCC system has detected the preceding vehicle, and the above-described information (2), are displayed as third information given to the driver by the display elements  120 ,  124 ,  126 . 
     As shown in  FIG. 11 , the first liquid crystal display unit  118   a  and the second liquid crystal display unit  118   b  are fixedly mounted onto a baseboard  130  by support members  132   a ,  132   b . A plurality of LEDs  134  for emitting white light, and an LED  136  for emitting amber light, are disposed on the surface of the baseboard  130  inside of the support members  132   a ,  132   b . A wall  138  extends from the baseboard  130  to the second liquid crystal display unit  118   b , with a clearance  140  remaining between the tip end of the wall  138  and the second liquid crystal display unit  118   b.    
     As shown in  FIG. 11 , some of the LEDs  134  are positioned on the right side of the wall  138 , and other LEDs  134 , and the LED  136 , are positioned on the left side of the wall  138 . As shown in  FIG. 12B , the wall  138  divides the display element  120  and the display element  122  from each other, as viewed from the second liquid crystal display unit  118   b  (see  FIG. 11 ) toward the baseboard  130 . 
     When the controller  142  energizes the TN display elements  116  and  124  through  128  (see  FIGS. 10A and 10B ), while also energizing the LEDs  134  on the right side of the wall  138  and the LED  136  on the left side of the wall  138 , white light emitted from the LEDs  134  on the right side of the wall  138  passes only through the display element  122  and is radiated outwardly, and amber light emitted from the LED  136  on the left side of the wall  138  passes only through the display element  120  and is radiated outwardly. As a result, the display element  116  displays “100 km/h”, for example, in white characters, while the display element  120  displays “BRAKE”, for example, in amber characters. Therefore, the first meter cluster panel  114  displays the display pattern shown in  FIG. 12B . 
     The driver can thus recognize that the present speed of the vehicle  110  is 100 km/h, and that the vehicle  110  needs to be braked, because the vehicle  110  is approaching a preceding vehicle. 
     Since the wall  138  is disposed between the LEDs  134  that emit white light and the LED  136  that emits amber light, white light emitted from the LEDs  134  is prevented from passing through the display element  120 , while amber light emitted from the LED  136  is prevented from passing through the display element  122 . 
     As shown in  FIG. 11 , the controller  142  is disposed on the surface of the baseboard  130  outside of the support member  132   b . The controller  142  controls energization of the display elements  116  and  120  through  128  (see  FIGS. 10A and 10B ), as well as energization of the LEDs  134 ,  136 , such that the display elements  116 ,  120  and  122  through  128  simultaneously display the first information, and the second information or the third information, which are required by the driver of the vehicle  110 , in a non-overlapping manner. 
     Specifically, the controller  142  controls the display elements  116  and  120  through  128  (see  FIGS. 10A and 10B ), as well as the LEDs  134 ,  136  (see  FIG. 11 ), in order to display the display patterns shown in  FIGS. 12A through 12C , for example. 
       FIG. 12A  shows a display pattern, which displays only the vehicle speed as first information on the display element  116 .  FIG. 12B  shows a display pattern, which displays the vehicle speed as first information on the display element  122 , and also displays information for prompting the driver to brake the vehicle  110  as third information on the display element  120 .  FIG. 12C  shows a display pattern, which displays the vehicle speed as first information on the display element  122 , displays information indicating that the vehicle  110  is approaching a preceding vehicle as third information on the display element  124 , and also displays the preset vehicle speed for the vehicle  110  on the display element  128 . 
     A comparison of  FIGS. 12A through 12C  reveals that the vehicle speed, serving as the first information, is displayed in a large size in  FIG. 12A , but is displayed in a small size in  FIGS. 12B and 12C , so as not to overlap the second information and third information. In  FIGS. 12B and 12C , the first information, together with the second information or the third information, are disposed next to each other. 
     As shown in  FIG. 9 , a second meter cluster panel  144  is also disposed on the instrument panel  112 . The second meter cluster panel  144  is positioned inside of a steering wheel  143  as viewed from the perspective of the driver. The second meter cluster panel  144  comprises a tachometer  146  disposed centrally on the display surface, for displaying engine rotational speed of the vehicle  110  as analog indications, a shift indicator  148  for displaying the speed reduction ratio of the transmission (not shown) of the vehicle  110 , an odometer and trip meter  150  for displaying mileage of the vehicle  110 , and a temperature gauge  152  for displaying the temperature outside of the vehicle  110 . The tachometer  146  is disposed centrally on a panel  154 , which serves as the display surface of the second meter cluster panel  144 . The odometer and trip meter  150 , and the temperature gauge  152 , are disposed in juxtaposed relation to each other below the tachometer  146 . The shift indicator  148  is disposed on the right side of the tachometer  146 . 
     The vehicular display device (first meter cluster panel)  114  according to the present embodiment, and the vehicle  110  which incorporates the vehicular display device  114  therein, are basically constructed as described above. Operations of the vehicular display device (first meter cluster panel)  114 , along with the vehicle  110 , shall be described below with reference to  FIGS. 9 through 12C . 
     Operations of the first meter cluster panel  114 , for changing indications on the first meter cluster panel  114  from the display pattern shown in  FIG. 12A  to the display pattern shown in  FIG. 12B  or  12 C when the vehicle-to-vehicle distance between the vehicle  110  and the preceding vehicle becomes smaller than the preset distance in the IHCC system, shall be described below. It is assumed that each of the display elements  116  and  120  through  128  comprises a TN liquid crystal display element. 
     First, operation of the first meter cluster panel  114 , for displaying the display pattern shown in  FIG. 12A , i.e., operation of the first meter cluster panel  114  when the vehicle-to-vehicle distance between the vehicle  110  and the preceding vehicle is the preset distance in the IHCC system, shall be described below. 
     The controller  142  (see  FIG. 11 ) energizes the display elements  120  through  128  (see  FIGS. 10A and 10B ) while also energizing all of the LEDs  134  on the baseboard  130 . White light emitted from the LEDs  134  passes through only the display element  116  and is radiated outwardly. The display element  116  displays “100 km/h”, for example, in white characters. As a consequence, the driver can recognize that, the current speed of the vehicle  110  is 100 km/h. 
     Next, operation of the first meter cluster panel  114 , while the IHCC system is in operation, for changing indications on the first meter cluster panel  114  from the display pattern shown in  FIG. 12A  to the display pattern shown in  FIG. 12B , when the vehicle-to-vehicle distance between the vehicle  110  (see  FIG. 9 ) and the preceding vehicle becomes smaller than the preset distance in the IHCC system, shall be described below. 
     The IHCC system judges that the vehicle speed needs to be lowered, and that the vehicle-to-vehicle distance needs to be increased up to the preset distance. The IHCC system outputs a signal to the controller  142  for prompting the driver to brake the vehicle  110  (see  FIG. 11 ). Based on the input signal, the controller  142  energizes the LEDs  134  on the right side of the wall  138  as well as the LED  136  on the left side of the wall  138 , while also energizing the display elements  116  and  124  through  128  (see  FIGS. 10A and 10B ). 
     White light emitted from the LEDs  134  on the right side of the wall  138  passes only through the display element  122  and is radiated outwardly. The display element  122  displays “100 km/h”, for example, in white characters. Amber light emitted from the LED  136  on the left side of the wall  138  passes only through the display element  120  and is radiated outwardly. The display element  120  displays “BRAKE”, for example, in amber characters. As a result, the driver can recognize that the current speed of the vehicle  110  is 100 km/h and that the vehicle  110  needs to be braked because the vehicle  110  is approaching the preceding vehicle. 
     Now, operation of the first meter cluster panel  114 , while the IHCC system is in operation, for changing indications on the first meter cluster panel  114  from the display pattern shown in  FIG. 12A  to the display pattern shown in  FIG. 12C , so as to inform the driver that the preceding vehicle is running ahead of the vehicle  110  (see  FIG. 9 ), shall be described. 
     The IHCC system outputs a signal to the controller  142  indicating that the IHCC system is in operation, and that the preceding vehicle is running ahead of the vehicle  110  (see  FIG. 11 ). Based on the input signal, the controller  142  energizes all of the LEDs  134  while also energizing the display elements  116 ,  120  (see  FIG. 10A ). 
     White light emitted from the LEDs  134  passes only through the display elements  122  through  128  and is radiated outwardly. The display element  122  displays “100 km/h”, for example, in white characters. The display element  124  displays a vehicle figure, representing the preceding vehicle, in white. The display element  128  displays “100 km/h” as the preset vehicle speed in the IHCC system in white characters. As a result, the driver can recognize that (1) the present speed of the vehicle  110  is 100 km/h, (2) the preceding vehicle is running ahead of the vehicle  110 , (3) the IHCC system is in operation, and (4) the preset speed of the vehicle  110  in the IHCC system is 100 km/h. 
     As described above, the vehicular display device (first meter cluster panel)  114  according to the present embodiment, and the vehicle  110  that incorporates the vehicular display device  114 , simultaneously display the first information together with the second information or the third information in a non-overlapping manner. Even when various items of information are displayed, movement of the driver&#39;s line of sight is kept relatively small. 
     The display element  116  of the first liquid crystal display unit  118   a  and the display element  122  of the second liquid crystal display unit  118   b , which display the first information (vehicle speed), are of different sizes. While the vehicle speed is being displayed by the display element  116  of the first liquid crystal display unit  118   a , and when the display elements  120  and  124  through  126  are operated to display the second information or the third information, the controller  142  controls the display elements  116  and  120  through  128  together with the LEDs  134 ,  136  in order to display the vehicle speed on the display element  122 . The display element  122  for displaying vehicle speed is smaller in size than the display element  116  for displaying vehicle speed. The display elements  116  and  120  through  128  can thus be arranged to display the first, second, and third information, without having to increase the liquid crystal display sizes of the first liquid crystal display unit  118   a  and the second liquid crystal display unit  118   b.    
     When the first, information, along with the second information or the third information, are displayed simultaneously by the first liquid crystal display unit  118   a  and the second liquid crystal display unit  118   b , the controller  142  controls the display elements  116  and  120  through  128  in order to display the first information, together with the second information or the third information, next to each other. Therefore, movement of the driver&#39;s line of sight is further reduced. 
     The display elements  116  and  120  through  128  can display other characters and figures, as described below, as well as the characters and figures that have been described above. The display element  124  can display a figure indicating that the IHCC system has not detected a preceding vehicle. The display element  126  can display characters “CMS NEAR” indicating that the vehicle  110  is approaching the preceding vehicle and could possibly hit the preceding vehicle from behind, characters “CMS FAR” indicating that the vehicle  110  is approaching the preceding vehicle, but is not close enough to hit the preceding vehicle from behind, characters “IHCC OFF” indicating that the IHCC system is not in operation, and characters “RADAR SMEARED” indicating that the transmitting/receiving unit of the radar has become dirty or smeared and thus is incapable of detecting a preceding vehicle. 
     The display elements  116  and  120  through  128  have been described as comprising segmented liquid crystal display elements. However, the display elements may also comprise dot-matrix liquid crystal display elements. In the above description, the LEDs  134  emit white light and the LED  136  emits amber light. However, the LEDs may be replaced with different LEDs that emit light in other colors. 
     Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.