JP2008049925A - Display device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device for vehicle capable of limiting the change in the display mode of a display when the external light quantity is temporarily reduced. <P>SOLUTION: The display device for vehicle is provided, which limits the change to a display mode for a dark state when a structure such as a three-dimensional intersection road and a railroad viaduct is present so as to block the reach of the external light on a vehicle traveling on a road; an instantaneous light-shading structure for instantaneous light blocking during the passage of the vehicle is present in the vehicle advancing direction; and the state around the vehicle is light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device for a vehicle that detects an external light quantity and automatically switches a screen of a display device between a day screen and a night screen.

  As the vehicle travels, the current position is detected by GPS (Global Positioning System), etc., and the current position is displayed on the display together with a road map, and an appropriate route from the starting point to the destination The vehicle-mounted navigation device that guides the user with a display or a voice output device contributes to efficient and safe driving for the user.

  There are a variety of display devices inside the vehicle and information displayed, such as in-vehicle navigation devices. As the types of display content increase, the improvement of the visibility has become one issue. As described above, as one means for improving the visibility of the display device, the brightness of the display device is adjusted according to the ambient brightness.

  For example, an in-vehicle display device has been devised that compares the estimated illuminance estimated from the time information with the estimated illuminance estimated from the travel position, and controls the brightness of the display based on the darker illuminance (Patent Literature). 1).

  In addition, in order to remove the influence of external light noise, noise due to sudden external light changes is removed by changing the sampling time for measuring the intensity of external light, and appropriate brightness adjustment is performed according to the usage environment. A display control method and a display control device that can be used have been devised (see Patent Document 2).

Japanese Patent Laid-Open No. 11-184446 JP 2001-142446 A

  In the configuration of Patent Document 1, there is a problem that the brightness of the display unit is lowered more than necessary due to a temporary decrease in the brightness of external light, and visibility is deteriorated.

  Moreover, in the structure of patent document 2, when the brightness of a display device needs to be darkened or brightened, especially when external light changes rapidly when the sampling time is long, there is a problem that the responsiveness deteriorates. appear. There is also a problem that the sampling process becomes complicated because the sampling time is changed.

  Moreover, in the above-described conventional technology, for example, when driving on a road under an overpass such as a road or a railroad (so-called underpass), the display mode is such that the brightness of the display becomes dark due to a temporary decrease in the amount of external light. May change and may be difficult for the user to see.

  Against the background of the above problems, an object of the present invention is to provide a vehicle display device that restricts a change in display mode of a display device in the case of a temporary decrease in external light amount.

Means for Solving the Problems and Effects of the Invention

  A vehicle display device for solving the above-described problems includes ambient light / dark information acquisition means for acquiring ambient light / dark information reflecting whether the surrounding state of the vehicle is a bright state or a dark state, and various types of electronic maps, etc. When the display means for displaying information and the content of the acquired ambient light / dark information indicate a bright state, the display form of the display means is the first display form for the bright state, and when the dark state is indicated The display form switching means which makes the display form of the display means a second display form for the dark state different from the first display form, and the object data of the road for displaying the travel route of the vehicle on the electronic map, Map data storage for storing object data of a light blocking structure that exists so as to block the arrival of external light to a vehicle traveling on a road and that instantaneously blocks light when the vehicle passes means A traveling direction detecting means for detecting the traveling direction of the vehicle, an instantaneous light shielding structure presence determining means for determining whether or not the instantaneous light shielding structure exists in the traveling direction of the vehicle, and an instantaneous light shielding structure exists, and And a display form switching restricting means for restricting switching to the second display form when the content of the acquired ambient light / dark information is in a bright state.

  With the above configuration, the instantaneous light shielding structure blocks the arrival of external light to the vehicle, and the problem is that the brightness of the display unit decreases more than necessary due to a temporary decrease in the brightness of external light and the visibility deteriorates. Does not occur. Further, there is no need to change the sampling time for measuring the intensity of external light, and there is no problem that the responsiveness deteriorates when the external light changes suddenly when the sampling time is long. Further, the problem that the sampling process becomes complicated does not occur.

  Moreover, the surrounding light / dark information acquisition means in the display apparatus for vehicles of this invention can also be comprised so that the lighting state information of the lighting device of a vehicle may be acquired as surrounding light / dark information.

  2. Description of the Related Art In recent years, an auto light system that senses the brightness of the surroundings of a vehicle and automatically turns on the light when it is determined that the light needs to be turned on, and turns off the light when it is determined that it is not necessary. When the outside light reaches the vehicle by the instantaneous light blocking structure, the light is turned on in this auto light system. Therefore, if the lighting state information of the auto light system is acquired, the surrounding state of the vehicle can be known. With the above configuration, the state around the vehicle can be acquired without providing a new device or circuit.

  The lighting device in the display device for a vehicle according to the present invention is an illumination sensor that detects illumination around the vehicle, and performs lighting / extinguishing control of a lighting unit of the lighting device based on an illumination input value from the illumination sensor. Control means, the ambient light / dark information acquisition means acquires the lighting state information from the lighting control means, the lighting control means compares the illuminance input value from the illuminance sensor with a predetermined threshold, and compares A comparison unit that outputs a binary lighting / extinguishing command signal to the lighting unit based on the result, and setting a dead band in a certain range including a threshold for the illuminance input value to the comparing unit, thereby the lighting / extinguishing command Short-cycle chattering prevention means for preventing chattering reversal based on a change in illuminance input shorter than the period of change in illuminance when passing through the instantaneous light shielding structure. It is also possible to.

  With the above configuration, it is possible to prevent a non-instantaneous light shielding structure such as a tree from being mistaken as an instantaneous light shielding structure. Also, in the auto light system, in order to prevent hunting that repeats blinking of the light in a short cycle, it is confirmed that the lighting / extinguishing command signal output is stable after performing annealing processing, etc. The light is turned off. For this reason, there is a delay of about several seconds from when the illuminance changes until when the light is actually turned on / off. On the other hand, in the configuration of the present invention, since the annealing process or the like is not performed, the response delay can be suppressed to a short period chattering prevention time, for example, about 1 to 2 seconds.

  Moreover, the display apparatus for vehicles of this invention can also be comprised so that the light-shielding structure in which the section length which produces light shielding is less than the predetermined value is defined as an instantaneous light-shielding structure.

  Since the section length of the instantaneous light shielding structure is defined as object data in the map data storage means, it is possible to easily determine whether it is an instantaneous light shielding structure or not with the above configuration.

  Further, the vehicle display device of the present invention estimates the passing time passing through the instantaneous light shielding structure from the vehicle speed detecting means for detecting the vehicle speed of the vehicle, the section length of the instantaneous light shielding structure and the detected vehicle speed. A display time switching limiting unit, and the display mode switching limiting unit may be configured to prohibit switching to the second display mode when the estimated passing time is less than a predetermined value.

  Even when the instantaneous light shielding structure has the same section length, the time required to pass (passing time) varies depending on the vehicle speed. When the vehicle speed is relatively low, that is, when the passage time is long, the light shielding time is also long, so it is necessary to switch to the second display mode. With the above configuration, the display mode can be appropriately switched according to the traveling state (vehicle speed) of the vehicle, and switching to the second display mode can be prohibited only when necessary.

  In addition, the vehicle display device of the present invention can be configured such that at least one of a three-dimensional intersection road and a railway viaduct with respect to a traveling road is defined as an instantaneous light shielding structure.

  Since the transit time when passing under the three-dimensional intersection road and the railway viaduct is relatively short, when switching to the second display mode, it is difficult for the user to see. However, according to the above configuration, when the vehicle passes under a three-dimensional intersection road and a railway viaduct, switching to the second display form is prohibited, so that the problem that the user feels difficult to see is solved.

  The map data storage means in the vehicle display device of the present invention stores road or railway object data together with the display width data of the road or railway, and the display width is less than a predetermined value. A three-dimensional intersection road or a railway viaduct based on a road or a railway can be configured as an instantaneous light shielding structure.

  Even if the section length of the road or railway is not stored in the map data, if there is display width data to be displayed on the display means, the actual section length can be obtained from the scale of the display. Also with the above configuration, the display mode can be appropriately switched according to the traveling state of the vehicle, and switching to the second display mode can be prohibited only when necessary.

  In the map data storage means of the vehicle display device of the present invention, the road or railway object data is described as a set of links whose end points are defined by node information that defines branch points, and the current position of the vehicle is determined. Position detection means for detecting, node information of a detected link that is a link representing a road on which the detected vehicle is currently traveling, and node information of an intersection determination target link that exists within a predetermined range with respect to the traveling link; Based on the above, it is checked whether the running link and the intersection determination target link have intersections at points other than the nodes that form both ends. And a display form switching restricting means for determining that the intersection determination target link and the traveling link are It is determined to be, and, when the contents of the acquired ambient brightness information of the bright state, may be configured to limit the switch to the second display mode.

  The electronic map data stored in the vehicle-mounted navigation device includes information on the above-described link and node. With the above-described configuration, it is possible to determine a link (a road, a railroad, or the like) that intersects the road on which the vehicle is currently traveling. Further, whether or not the vehicle is traveling on the underpass of the three-dimensional intersection can be determined based on ambient light / dark information. Therefore, it is not necessary to store data representing the top and bottom of the three-dimensional intersection in the electronic map data. That is, the effects of the present invention can be obtained not only when the electronic map data is three-dimensional data but also when the electronic map data is existing two-dimensional data.

  Hereinafter, an example in which the vehicle display device of the present invention is configured as a part of the function of an in-vehicle navigation device will be described with reference to the drawings. Of course, it is good also as a structure independent as a display apparatus for vehicles, and it is good also as a structure as a part of other vehicle equipment. FIG. 1 is a block diagram showing the configuration of an in-vehicle navigation device (hereinafter abbreviated as navigation device) 100. The navigation device 100 includes a position detector 1, a map data input device 6, an operation switch group 7, a remote control (hereinafter referred to as remote control) sensor 11, a voice synthesis circuit 24 for performing voice guidance, a speaker 15, a memory 9, and a display. 10, a transceiver 13, a hard disk device (HDD) 21, a LAN (Local Area Network) I / F (interface) 26, a control circuit 8 connected thereto, a remote control terminal 12, and the like.

  The position detector 1 is a well-known geomagnetic sensor 2, a gyroscope 3 that detects the rotational angular velocity of the vehicle, a distance sensor 4 that detects the travel distance of the vehicle, and a GPS receiver that detects the position of the vehicle based on radio waves from a satellite. Machine 5 is provided. Since these sensors 2, 3, 4, and 5 have errors of different properties, they are configured to be used while being complemented by a plurality of sensors. Depending on the accuracy, some of the above-described sensors may be used, and further, a steering rotation sensor or a wheel sensor of each rolling wheel, such as a vehicle speed sensor 23, may be used. The position detector 1 corresponds to the position detecting means and the traveling direction detecting means of the present invention.

  As the operation switch group 7, for example, a touch panel 22 integrated with the display device 10 or a mechanical switch is used. The touch panel 22 is pressed when an electric circuit is wired on the screen of the display 10 in the X-axis direction and the Y-axis direction through a gap called a spacer on a glass substrate and a transparent film, and the user touches the film. Since the voltage value changes due to short-circuiting of a part of the wiring, a so-called resistance film method for detecting this as a two-dimensional coordinate value (X, Y) is widely used. In addition, a known so-called capacitance method may be used. In addition to the mechanical switch, a pointing device such as a mouse or a cursor may be used. Moreover, you may arrange | position the mechanical switch of the operation switch group 7 in the escutcheon which covers the indicator 10 and its periphery and becomes a design frame.

  It is also possible to input various instructions using the microphone 31 and the voice recognition unit 30. In this method, a voice signal input from the microphone 31 is processed by a voice recognition technique such as a well-known hidden Markov model in the voice recognition unit 30, and converted into an operation command corresponding to the result. Various instructions can be input through the operation switch group 7, the remote control terminal 12, the touch panel 22, and the microphone 31.

  The transmitter / receiver 13 is connected to a road traffic from a VICS (Vehicle Information and Communication System) center 14 by an optical beacon or a radio beacon output from a transmitter (not shown) provided along the road, for example. It is a device for receiving information or receiving FM multiplex broadcasting. Moreover, it is good also as a structure which can be connected to external networks, such as the internet, using the transmitter / receiver 13. FIG.

  Further, by communicating with the ETC on-vehicle device 17, it is possible to capture the fee information received by the ETC on-vehicle device 17 from the roadside device (not shown) into the navigation device 100. Further, the ETC on-vehicle device 17 may be connected to an external network and communicate with the VICS center 14 or the like.

  The control circuit 8 is configured as a normal computer, and connects a well-known CPU 81, ROM 82, RAM 83, I / O 84 as an input / output circuit, A / D conversion unit 86, drawing unit 87, clock IC 88, and these components. A bus line 85 is provided. The CPU 81 controls the navigation program 21p and data stored in the HDD 21. The CPU 81 controls the reading / writing of data to / from the HDD 21. In addition, a program for performing a minimum necessary operation as the navigation device 100 may be stored in the ROM 82 in a case where the data read / write control from the CPU 81 to the HDD 21 becomes impossible. The control circuit 8 corresponds to the display form adjusting means, the instantaneous light shielding structure presence judging means, the display form switching restricting means, the passing time estimating means, and the three-dimensional intersection judging means of the present invention.

  The A / D conversion unit 86 includes a well-known A / D (analog / digital) conversion circuit, and converts analog data input from the position detector 1 or the like to the control circuit 8 into digital data that can be calculated by the CPU 81, for example. It is.

  The drawing unit 87 generates display screen data to be displayed on the display unit 10 from map data 21m (described later) stored in the HDD 21 or the like, display data, and display color data.

  The clock IC 88 is also called a real-time clock IC, and sends or sets clock / calendar data in response to a request from the CPU 81. The CPU 81 acquires date / time information from the clock IC 88. Further, date and time information included in the GPS signal received by the GPS receiver 5 may be used. The date information may be generated based on a real-time counter included in the CPU 81. The acquired date / time information is used, for example, for travel history management.

  In addition to the navigation program 21p, the HDD 21 stores so-called map matching data for improving the accuracy of position detection, and map data 21m, which is a map database including road data representing road connections. The map data 21m stores predetermined map image information for display and road network information (object data of the present invention) including link information and node information. An example is shown in FIG. The link information is predetermined section information constituting each road, and includes position coordinates, distance, required time, width, number of lanes, speed limit, and the like in the link attributes. The node information is information that defines an intersection (branch road) or the like, and includes position coordinates, the number of right / left turn lanes, a connecting road link, a distance cost, and the like. In addition, data indicating whether or not traffic is possible is set in the inter-link connection information. The map data 21m corresponds to the map data storage means of the present invention. The object data A and B in FIG. 2 correspond to roads or railways.

  Further, as shown in FIG. 3, the link attribute may include display width data for display on the display device 10. The display width is represented by the number of display dots on the display 10.

  Returning to FIG. 1, auxiliary information for route guidance, entertainment information, and other data can be written by the user in the HDD 21 and stored as user data 21 u. Data and various information necessary for the operation of the navigation device 100 are also stored as the database 21d.

  The navigation program 21p, map data 21m, user data 21u, and database 21d can be added and updated from the storage medium 20 via the map data input device 6. The storage medium 20 is generally a CD-ROM or DVD based on the amount of data, but may be another medium such as a memory card. Moreover, you may use the structure which downloads data via an external network.

  The memory 9 is composed of a rewritable device such as an EEPROM (Electrically Erasable & Programmable Read Only Memory) or a flash memory, and stores information and data necessary for the operation of the navigation apparatus 100. Has been. The memory 9 holds the stored contents even when the navigation device 100 is turned off. Further, instead of the memory 9, information and data necessary for the operation of the navigation device 100 may be stored in the HDD 21. Further, information and data necessary for the operation of the navigation device 100 may be stored separately in the memory 9 and the HDD 21.

  The display 10 is composed of a known color liquid crystal display, and includes a dot matrix LCD (Liquid Crystal Display) and a driver circuit (not shown) for performing LCD display control. The driver circuit uses, for example, an active matrix driving method in which a transistor is attached to each pixel so that the target pixel can be reliably turned on and off, and a display command sent from the control circuit 8 (drawing unit 87) and Display is performed based on the display screen data. Further, an organic EL (ElectroLuminescence) display or a plasma display may be used as the display 10. The display device 10 corresponds to the display means of the present invention.

  The speaker 15 is connected to a well-known voice synthesis circuit 24, and the digital voice data stored in the memory 9 or the HDD 21 in accordance with a command from the navigation program 21p is converted into analog voice by the voice synthesis circuit 24 and sent out. Note that speech synthesis methods include a recording / editing method in which speech waveforms are stored as they are or after being encoded and connected as necessary, and a text synthesis method in which corresponding speech is synthesized from character input information.

  The vehicle speed sensor 23 includes a rotation detection unit such as a known rotary encoder. For example, the vehicle speed sensor 23 is installed in the vicinity of the wheel mounting unit to detect the rotation of the wheel and send it to the control circuit 8 as a pulse signal. The control circuit 8 converts the rotation speed of the wheel into the speed of the vehicle, calculates the expected arrival time from the current position of the vehicle to a predetermined location, and calculates the average vehicle speed for each travel section of the vehicle. The vehicle speed sensor 23 corresponds to the vehicle speed detection means of the present invention.

  The LAN I / F 26 is an interface circuit for exchanging data with other in-vehicle devices and sensors via the in-vehicle LAN 27. Further, data may be taken from the vehicle speed sensor 23 or connected to the ETC on-vehicle device 17 via the LAN I / F 26.

  With this configuration, when the navigation program 21p is activated by the CPU 81 of the control circuit 8, the navigation device 100 allows the user to operate the operation switch group 7, the touch panel 22, the remote control terminal 12, or the voice from the microphone 31. When a route guidance process for displaying a destination route on the display 10 is selected from a menu (not shown) displayed on the display 10 by input, the following process is performed.

  That is, first, the user searches for a destination. The destination search method includes, for example, a method of specifying an arbitrary point on the map, a method of searching from the area where the destination is located, a method of searching from the telephone number of the destination, and a name of the destination from the Japanese syllabary table There are a method of searching by inputting the number of characters stored in the memory 9 as a facility frequently used by the user. When the destination is set, the current position of the vehicle is obtained by the position detector 1, and a process for obtaining an optimum guide route to the destination from the current position is performed. Then, the guidance route is displayed on the road map on the display 10 so as to guide the user to the appropriate route. As a method for automatically setting an optimum guide route, a method such as the Dijkstra method is known. In addition, at least one of the display 10 and the speaker 15 performs notification of a message according to an operation guidance or an operation state.

  In addition, an illumination detection device 19 is connected to the navigation device 100. FIG. 4 shows a configuration example of the illumination detection device 19. The illumination detection device 19 includes a control unit 19a including a CPU 19a1, a ROM 19a2, etc., a sensor unit 19b, an input / output circuit 19c for exchanging signals with an external device, etc., and a control (not shown) stored in the ROM 19a2 by the CPU 19a1. By executing the program, it is determined whether the surrounding state of the vehicle is a bright state or a dark state, and lighting / extinguishing control of the lighting unit including the headlight lamp of the lighting device 20 is performed. That is, a command signal for instructing lighting / extinguishing is output to an external device such as the lighting device 20. Further, the control program does not determine that the state around the vehicle has changed due to a short-cycle state change from the sensor unit 19b, and waits for a predetermined time until the state becomes stable after the change of the state of the sensor unit 19b. For example, an annealing process for preventing hunting of the command signal is included. The illumination detection device 19 corresponds to the ambient light / dark information acquisition unit of the present invention, and the control unit 19a corresponds to the lighting control unit of the present invention.

  FIG. 5 shows a configuration example of the sensor unit 19b. Illuminance sensor S using a CdS cell, which is a known photoconductive element mainly composed of cadmium sulfide, an adjustment resistor VR for setting a threshold value for comparison with an illuminance input value from the illuminance sensor S, a resistance R1 and R2 and an operational amplifier OP that operates as a comparator. The resistor R1 sets the input to the operational amplifier OP to an appropriate value according to the characteristics of the illuminance sensor S and the voltage of the power supply V. The comparator amplifies the difference between the + and-inputs of the operational amplifier OP, and since the amplification degree is infinitely large, the output Vo is the maximum value V1 of the output voltage of the operational amplifier OP when the illuminance input value is larger than the threshold value. Thus, when the illuminance input value is smaller than the threshold value, the output voltage becomes the minimum value V2 of the operational amplifier OP. Since the illuminance sensor S generates a voltage proportional to the illuminance, the controller 19a outputs a turn-off instruction when Vo = V1, and outputs a turn-on instruction when Vo = V2. The operational amplifier OP corresponds to the comparison means of the present invention.

  The sensor unit 19b constitutes a known Schmitt circuit that performs positive feedback using the resistor R2. Since hysteresis is generated by the adjusting resistor VR and the resistor R2, in order to invert the output Vo, the illuminance input value needs to be different from the reference voltage by this hysteresis, and the output Vo fluctuates near the reference voltage. Can be prevented. For example, if the reference voltage is 2.5V and the hysteresis is 0.5V, the output Vo is inverted when the illuminance input value exceeds 3.0V, which is the reference voltage plus hysteresis, and the output voltage is inverted when the illuminance input value decreases. The output Vo is inverted when less than 2.0V minus. The resistor R2 corresponds to the short period chattering preventing means of the present invention, and the hysteresis corresponds to the dead zone of the present invention.

  The display mode switching restriction process will be described with reference to FIG. This process is included in the navigation program 21p and is repeatedly executed together with other processes of the navigation program 21p. First, the control circuit 8 acquires lighting state information (ambient light / dark information) from the illumination detection device 19 (S11). When the acquired lighting state information does not include a lighting command such as “Headlight ON” (S12: No), the screen mode (display mode) of the display 10 is set to the day screen mode (No) because it is in the bright state. First display form of the present invention). The day screen mode is a normal display mode of the navigation device, and is set to a color tone, luminance, and contrast that can be visually recognized at daytime (the bright state of the present invention). The display mode set this time is stored in a predetermined area of the memory 9 or the RAM 83.

  The lighting state information is output from the input / output circuit 19c of the illumination detection device 19, that is, an output after a predetermined annealing process is performed by the control unit 19a, or an output (Vo) from the sensor unit 19b. ) May be used. If the output after being processed by the control unit 19a is used, it is possible to suppress the screen mode from changing in a short time because there is little hunting of the lighting state. In addition, when the output from the sensor unit 19b is used, the response time of this process with respect to a change in illuminance can be shortened.

  On the other hand, when the lighting command is included (S12: Yes), it is determined that the state is dark. Then, referring to the memory 9 or the RAM 83, the screen mode set in the previous display mode switching restriction process is checked, and in the case of the night screen mode (second display mode of the present invention) (S14: No), the screen remains as it is. The display is performed in the mode (S19 → S18).

  On the other hand, in the daytime screen mode (S14: Yes), in order to determine whether it is temporary headlight ON information, the current position of the vehicle is obtained from the position detector 1 and the traveling direction of the vehicle is obtained, and the map data Referring to 21m, it is examined whether there is a road (that is, a light shielding structure of the present invention) that protects roads, railways, or roads that intersect three-dimensionally in the traveling direction of the current position of the vehicle from landslides and avalanches. When the light shielding structure exists (S15: Yes), the width (section length) included in the link information of the light shielding structure included in the map data 21m is referred to. The traveling direction of the vehicle may be obtained from a change in the current position of the vehicle, or may be obtained from a change in the rotation angle with respect to the reference direction using the rotation angular velocity of the vehicle detected by the gyroscope 3.

  The process for determining the presence or absence of roads, railways, etc. that intersect with each other will be described later. In this process, it is not necessary to determine whether the vehicle is traveling above or below a three-dimensional intersection. When driving on the upper side of a three-dimensional intersection, the headlight is not turned on because the outside light is not blocked. That is, it is possible to determine the traveling position at the three-dimensional intersection based on whether or not the headlight (lighting device) is turned on. Therefore, it is not necessary to store information that the road intersects with another road or a railroad in the map data 21m or the like. The effect of the present invention can be obtained even in a navigation apparatus having only map data for two-dimensional display.

  When the section length exceeds a predetermined reference value such as 12 m (S16: No), it is determined that the instantaneous light shielding structure of the present invention is not used, and the screen mode (display mode) of the display 10 is changed to night. The screen mode (second display mode of the present invention) is set (S19). The night screen mode is set to a color tone / brightness / contrast that can be visually recognized at night (the dark state of the present invention). For example, the night screen mode is displayed by lowering the brightness or using a dark color. At this time, the display mode set this time is stored in a predetermined area of the memory 9 or the RAM 83.

  On the other hand, when the section length is equal to or smaller than a predetermined reference value (S16: Yes), it is determined as the instantaneous light shielding structure of the present invention, and the screen mode (display mode) of the display 10 is set to the day screen mode (the first screen of the present invention One display form) (S17). The display mode set this time is stored in a predetermined area of the memory 9 or the RAM 83.

  Finally, electronic map data and the like are displayed in the set screen mode (S18).

  In the condition determination in step S16, the display width data (see FIG. 3) described above may be used instead of the section length. When the display width data is represented by the number of display dots of the display device 10, the section length can be obtained from the dot diameter, display dot number, and scale determined by the specifications of the display device 10. At this time, when the display width data falls below a predetermined reference value, it is determined as the instantaneous light shielding structure of the present invention.

  An example of display mode switching restriction will be described with reference to FIGS. FIG. 7 shows a running vehicle and a map around it, and the current position of the vehicle is indicated by P (a mark combining ◯ and ▲). FIG. 8 shows nodes (N) and links (L) in the map of FIG. FIG. 9 shows the correspondence between nodes and links in FIGS. In FIGS. 7 and 8, the upper side of the drawing is the north direction. When the vehicle passes under the three-dimensional intersection road 53 while traveling, the illumination detection device 19 outputs a lighting command signal because the arrival of external light to the vehicle is blocked. Then, referring to the link information of the map data 21m, the width (section length) of the three-dimensional intersection road 53 is less than a predetermined value, so that the screen mode of the display 10 remains the day screen mode. Similarly, when the vehicle passes under the railway viaduct 59 and when it passes through the first tunnel 64, the screen mode of the display 10 remains the day screen mode.

  On the other hand, when passing through the second tunnel 67, since the section length exceeds a predetermined value, the screen mode of the display 10 changes to the night screen mode.

  By performing the above processing, it is possible to prevent unnecessary switching to the night screen when traveling under a multi-level crossing road or railway viaduct, and to switch to the night screen when the headlight is turned on during tunnel or night driving. Switching can be performed smoothly.

  A solid intersection determination process for determining whether a solid intersection is present will be described with reference to FIGS. This process is executed prior to the condition determination in step S15 in FIG. First, the coordinates of the nodes N1 and N2 at both ends of the traveling link L1 including the current position Q of the vehicle shown in FIG. 11 are acquired from the map data 21m (S31). The acquired coordinates are (x1, y1) and (x2, y2), respectively. The link L1 is expressed as the following formula 1 using the coordinates of the nodes N1 and N2.

  Next, a node N3 closest to the current position (vehicle position) Q of the vehicle other than the nodes N1 and N2 at both ends of the traveling link L1 is searched (S32). The coordinates of the node N3 are (x3, y3). Then, the node N4, which is the other end of the link including the node N3 (intersection determination target link L2), is searched with reference to the map data 21m (S33). The coordinates of the node N4 are (x4, y4). The link L2 is expressed as the following Expression 2 using the coordinates of the nodes N3 and N4.

  From the nodes N1 and N2 and the nodes N3 and N4 searched above, an intersection K0 between the links L1 and L2 including these nodes is calculated (S34). The X coordinate x0 of the intersection point k0 is expressed as Equation 3 below.

  If the X coordinate x0 of the intersection point K0 calculated above is in the range of x1 <x0 <x2 (S35: Yes), it can be determined that the links L1 and L2 are three-dimensionally crossed (S39). This is because if two links intersect on a plane, it becomes an intersection, and this intersection is represented as a node. That is, x0 = x1 or x0 = x2.

  If the links L1 and L2 are not three-dimensionally crossed (S35: No), if it is not checked whether or not all links including the node N3 are three-dimensionally crossed with the link L1 (S36: No), step S33 Referring back to the node information, a link different from the above-described link L2 including the node N3 is searched, and if there is a link, the other end node is searched. Then, it is checked whether or not a new link including the searched node crosses the link L1 (S34).

  When it is determined whether or not all the links including the node N3 are three-dimensionally intersected with the link L1 (S36: Yes), for example, when there is a node other than the node N3 within a predetermined range from the link L1 such as 1 km ( S37: Yes), a link including the node is searched, and a node included in the searched link is searched (S38). Then, the process returns to step S34, and it is checked whether or not a solid intersection with the link L1 is made using the searched new link and node pair.

  Another example of the display form switching restriction process will be described with reference to FIG. Note that steps S51 to S55 and S57 to S59 of this process are the same as steps S11 to S15 and S17 to S19 of FIG. 6, so detailed description thereof will be omitted, and only step S56 will be described.

  When the light shielding structure exists (S55: Yes), the width (section length) included in the link information of the light shielding structure included in the map data 21m is referred to. Next, the vehicle speed is acquired from the vehicle speed sensor 23. Then, the passage time of the light shielding structure is estimated and calculated from the section length and the vehicle speed.

  When the passage time exceeds a predetermined reference value such as 5 seconds (S56: No), the screen mode (display mode) of the display 10 is set to the night screen mode (S59). On the other hand, when the section length is equal to or smaller than a predetermined reference value (S56: Yes), it is determined as the instantaneous light shielding structure of the present invention, and the screen mode of the display 10 is set to the daytime screen mode (S57). The display mode set this time is stored in a predetermined area of the memory 9 or the RAM 83.

  In the condition determination in step S56, the above-described display width data (see FIG. 3) may be used instead of the section length. As described above, the section length can be obtained from the display width data and the scale, and the passing time can be estimated and calculated.

  Although the embodiments of the present invention have been described above, these are merely examples, and the present invention is not limited to these embodiments, and the knowledge of those skilled in the art can be used without departing from the spirit of the claims. Various modifications based on this are possible.

The block diagram which shows the structure of a vehicle-mounted navigation apparatus. The figure which shows the structural example of link information and node information. The figure which shows another example of the content of a link attribute. The block diagram which shows the structural example of an illumination detection apparatus. The figure which shows the structural example of a sensor part. The flow figure explaining a display form change restriction process. The figure explaining the example of a display form switching restriction | limiting. The figure which shows the node and link in the map of FIG. The figure which shows the correspondence of a node and a link. The flowchart explaining a three-dimensional intersection determination process. The figure explaining a three-dimensional intersection determination process. The flow figure explaining another example of a display form change restriction process.

Explanation of symbols

1 Position detector (position detection means, travel direction detection means)
7 Operation switch group 8 Control circuit (display mode adjusting means, instantaneous light blocking structure presence determining means, display mode switching limiting means, passing time estimating means, three-dimensional intersection determining means)
10 Display (display means)
12 Remote control terminal 15 Speaker 19 Illumination detection device (Ambient light / dark information acquisition means)
19a Control part 19b Sensor part OP Operational amplifier (comparison means)
R2 resistance (short cycle chattering prevention means)
S Illuminance sensor (Ambient light / dark information acquisition means)
21 Hard disk drive (HDD)
21d database 21m map data (map data storage means)
22 Touch panel 23 Vehicle speed sensor (vehicle speed detection means)
24 voice synthesis circuit 31 microphone 87 drawing unit 100 vehicle-mounted navigation device

Claims (8)

Ambient light / dark information acquisition means for acquiring ambient light / dark information reflecting whether the surrounding state of the vehicle is a bright state or a dark state;
Display means for displaying various information such as an electronic map;
When the content of the acquired ambient light / dark information indicates the bright state, the display form of the display means is the first display form for the bright state, and when the content indicates the dark state, the display means A display form switching means that makes the display form of the second display form for the dark state different from the first display form,
On the electronic map, a light-blocking structure that exists together with road object data for displaying a travel route of the vehicle, and that blocks outside light from reaching the vehicle traveling on the road, Map data storage means for storing object data of an instantaneous light-blocking structure that generates instantaneous light-blocking when passing through;
Traveling direction detection means for detecting the traveling direction of the vehicle;
Instantaneous light shielding structure presence determining means for determining whether or not the instantaneous light shielding structure exists in the traveling direction of the vehicle;
Display mode switching limiting means for limiting switching to the second display mode when the instantaneous light blocking structure exists and the content of the acquired ambient light / dark information is in the bright state;
A vehicle display device comprising:   The vehicle display device according to claim 1, wherein the ambient light / dark information acquisition unit acquires lighting state information of a lighting device of the vehicle as the ambient light / dark information. The lighting device includes an illuminance sensor that detects illuminance around the vehicle, and a lighting control unit that performs lighting / extinguishing control of a lighting unit of the lighting device based on an illuminance input value from the illuminance sensor,
The ambient light / dark information acquisition means acquires the lighting state information from the lighting control means,
The lighting control unit compares an illuminance input value from the illuminance sensor with a predetermined threshold value, and outputs a binary lighting / extinguishing command signal for the lighting unit based on the comparison result; By setting a certain range of dead zone including the threshold value for the illuminance input value to the comparison means, the lighting / extinguishing command signal output has a shorter period than the illuminance change period when passing through the instantaneous light shielding structure. The vehicle display device according to claim 2, further comprising short cycle chattering preventing means for preventing chattering reversal based on a change in illuminance input.   The vehicle display device according to any one of claims 1 to 3, wherein the light shielding structure in which the section length causing the light shielding is less than a predetermined value is defined as the instantaneous light shielding structure. Vehicle speed detecting means for detecting the vehicle speed of the vehicle;
From the section length of the instantaneous light shielding structure and the detected vehicle speed, a passing time estimation means for estimating a passing time passing through the instantaneous light shielding structure,
5. The vehicle according to claim 1, wherein the display form switching restriction unit prohibits switching to the second display form when the estimated passage time is less than a predetermined value. 6. Display device.   The vehicle display device according to any one of claims 1 to 5, wherein at least one of a three-dimensional intersection road and a railway viaduct with respect to a traveling road is defined as the instantaneous light shielding structure. The map data storage means stores road or railway object data together with display width data of the road or railway,
The vehicle display device according to claim 6, wherein a road or rail-based three-dimensional crossing road or railroad viaduct whose display width is less than a predetermined value is determined as the instantaneous light shielding structure. In the map data storage means, the object data of the road or the rail is described as a set of links whose end points are defined by node information that defines branch points,
Position detecting means for detecting a current position of the vehicle;
Based on node information of a traveling link that is a link representing a road on which the detected vehicle is currently traveling, and node information of an intersection determination target link existing within a predetermined range with respect to the traveling link, the traveling It is checked whether or not the middle link and the intersection determination target link have an intersection at a point other than the nodes that form both ends of the link. A solid intersection judging means for judging that
The display form switching restricting means determines that the intersection determination target link is three-dimensionally intersected with the traveling link by the three-dimensional intersection determining means, and the content of the acquired ambient light / dark information is in the bright state. The vehicle display device according to claim 6 or 7, wherein switching to the second display mode is limited.

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