JP2007091030A - On-vehicle display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle display device capable of giving an user necessary information regardless brightness of a display screen. <P>SOLUTION: The on-vehicle display device is provided, which has a brightness controlling means for adjusting the brightness of a screen of an indicator by adjusting a tone of color indicated in the screen of the indicator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-vehicle display device that is mounted on a vehicle and displays various information.

  In recent years, an image display device such as a liquid crystal display (LCD) is used in addition to a conventional mechanical meter as a display device for a vehicle instrument panel. This image display device has the advantage that the design and layout of the display can be freely set. Therefore, in addition to the conventional meter display, a vehicle display device has been devised in which a screen display of a vehicle-mounted navigation device is displayed in this image display device. (See Patent Document 1).

JP 2004-157434 A

  In the color liquid crystal display used in the vehicle display device of Patent Document 1, the brightness of the entire display screen is adjusted by the brightness of the backlight. In addition, in a self-luminous display such as an organic EL (Electro Luminescence), brightness is adjusted by uniformly suppressing the entire output voltage (or current). However, even when displaying information that should be informed to the user as soon as possible, such as a warning display, the display is also displayed with the same brightness as the display screen. Therefore, there is a problem that the user does not notice the information when the display screen is dark. .

  With the above problem as a background, an object of the present invention is to provide an in-vehicle display device capable of notifying a user of necessary information regardless of the brightness of a display screen.

Means for Solving the Problems and Effects of the Invention

  This invention provides the vehicle-mounted display apparatus for solving the said subject. In other words, according to the first aspect of the present invention, the vehicle-mounted display device has brightness control means for adjusting the brightness of the display screen by adjusting the gradation of the color displayed on the display screen. Configured as

  For example, in a liquid crystal display that adjusts the brightness of the display by adjusting the brightness of the backlight, a method of changing the brightness of the backlight according to the voltage applied to the backlight as shown in FIG. The applied voltage is changed by the duty ratio of PWM (Pulse Width Modulation). For example, the daytime mode (brightness 5) / nighttime mode (brightness 3) is set according to the stage (brightness) of the backlight luminance.

  On the other hand, in the configuration of the present invention, the brightness of the backlight is constant as shown in FIG. 4, but the brightness of the screen of the display can be made variable. This is because even with the same red color, the brightness of the color can be expressed by adjusting the gradation of the color such as “bright red” and “dark red”. With the above configuration, it is possible to configure an in-vehicle display device that adjusts the brightness of the screen of the display by adjusting the gradation of the color displayed on the screen of the display. Further, by making the luminance of the backlight constant, a circuit that makes the applied voltage to the backlight variable, such as PWM, becomes unnecessary, and the cost can be reduced accordingly. In addition, since the lifetime of the backlight tends to increase when the applied voltage (luminance) is lowered, the luminance of the backlight is minimized so that the user can visually recognize the display screen as in the configuration of the present invention. If an appropriate voltage is applied, the lifetime of the backlight can be extended.

  According to claim 2, the brightness control means in the in-vehicle display device of the present invention is configured to vary the brightness of the display area of the display information according to the type of display information displayed on the screen of the display. Can take.

  With the above configuration, even when the brightness of the screen of the display such as the night mode (brightness 3 in FIG. 4) is dark, for example, a display that should be promptly notified to the user, such as a warning display, is displayed only in the display area. It is possible to display with the maximum brightness (brightness 5 in FIG. 4). In addition, it is possible to set a display area on the display screen of the liquid crystal display for various warning lamps such as lamps and LEDs that have been installed independently of the conventional liquid crystal display. This eliminates the need for lamps, LEDs, and their wiring, thereby reducing component costs, wiring costs, and the like. Further, by consolidating lamps and LEDs into the display device, the space occupied by the display device can be reduced, and the degree of freedom of design design in the vehicle is increased.

  According to the third aspect, the in-vehicle display device of the present invention has gradation storage means for storing gradation corresponding to the brightness of the screen of the display and the type of display information, and the brightness control means It is possible to adopt a configuration in which the display information is displayed based on the gradation that has been set.

  In general, a color is expressed in steps (gradations) of color depth such as 16 gradations and 256 gradations. With the above configuration, if the gradation corresponding to the brightness level is stored, the processing time for determining the brightness of the display information can be shortened.

  According to the fourth aspect of the present invention, the in-vehicle display device of the present invention has a gradation calculating means for calculating a gradation for displaying display information corresponding to the brightness of the screen of the display and the type of display information. Configuration can be taken.

  With the above configuration, it is possible to determine the brightness of the display information even in a configuration that does not store the gradation corresponding to the brightness level.

  According to claim 5, the gradation calculation means in the in-vehicle display device of the present invention is configured to multiply the reference gradation by a predetermined coefficient corresponding to the brightness of the display screen and the type of display information. it can.

  The predetermined coefficient is defined by, for example, primary colors for expressing colors such as RGB (red, green, blue) which are the three primary colors of light and the brightness of the screen of the display, so at least (number of primary colors) × It suffices if there are as many storage areas as (number of screen brightness steps). With the above configuration, it is possible to reduce the area for storage, and it is possible to further shorten the processing time for determining the brightness of the display information.

  According to the sixth aspect of the present invention, the in-vehicle display device of the present invention can have a configuration having information acquisition means for acquiring display information from an external device.

  Various sensors and in-vehicle devices are installed in the vehicle. With the above-described configuration, information that should be promptly notified to the user by information from these sensors and in-vehicle devices can be easily noticed by the user by displaying the information with the brightness maximized. In addition, since information from sensors and in-vehicle devices can be displayed on a single display, the user only has to pay attention to the display on the display, and the number of eye movements during driving is reduced. Further, the space occupied by the display can be reduced, and the degree of freedom in designing the design in the vehicle is increased.

  For the purpose of providing an in-vehicle display device capable of notifying the user of necessary information regardless of the brightness of the display screen, the gradation of the color for displaying the predetermined information is displayed as brighter than other display areas. Realized by configuration.

  Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. FIG. 1 is a block diagram showing a configuration when an in-vehicle display device of the present invention is applied to an in-vehicle navigation device (hereinafter abbreviated as a navigation device) 100. In addition, the application range of the vehicle-mounted display device of the present invention is not limited to the vehicle-mounted navigation device (100), and may be applied to, for example, a display device installed on a vehicle instrument panel. Moreover, it is good also as a structure which includes a navigation screen in the display apparatus installed in the instrument panel of a vehicle.

  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 nonvolatile memory 9, a display And a hard disk device (HDD) 21, a control circuit 8 connected thereto, and a remote control terminal 12.

  The position detector 1 includes a known geomagnetic sensor 2, a gyroscope 3, a distance sensor 4, and a GPS receiver 5 that detects the position of the vehicle based on radio waves from a satellite. 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.

  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, using a so-called capacitance method, a substance that receives an electrical signal is applied to the glass surface of a transparent conductive substrate, and a change in capacitance is detected by the sensor as an electrical signal when a finger is brought close to the glass surface. Also good. In addition to the mechanical switch, a pointing device such as a mouse or a cursor may be used.

  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, and the microphone 31.

  The transceiver 13 which is the information acquisition means of the present invention is a device for receiving road traffic information from, for example, a VICS (Vehicle Information and Communication System) center 14.

  Further, by communicating with an ETC (Automatic Toll Collection System, ETC: Electronic Toll Collection) vehicle-mounted device 16, the fee information received from the ETC road device (not shown) by the ETC vehicle-mounted device 16 is taken into the navigation device 100. be able to. Further, the ETC vehicle-mounted device 16 may be connected to an external network and communicate with the VICS center 14.

  The control circuit 8 which is the brightness control means and gradation calculation means of the present invention is configured as a normal computer, and connects the well-known CPU 81, ROM 82, RAM 83, I / O 84 which is an input / output circuit, and these configurations. 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. 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 ROM 82 may store a program for performing a minimum necessary operation among the navigation functions when the HDD 21 fails.

  The drawing unit 87 generates drawing data to be displayed on the display unit 10 from display data and display color data stored in the HDD 21 or the like.

  In addition to the navigation program 21p, so-called map matching data for improving the accuracy of position detection and map data 21m including road data representing road connections are stored in the HDD 21, which is also the gradation storage means of the present invention. . The map data 21m stores predetermined map image information for display and road network information including link information and node information. The link information is predetermined section information constituting each road, and includes position coordinates, distance, required time, road width, number of lanes, speed limit, and the like. The node information is information that defines an intersection (branch road) and the like, and includes position coordinates, the number of right / left turn lanes, a connection destination road link, and the like. In addition, data indicating whether or not traffic is possible is set in the inter-link connection information.

  In addition, in the HDD 21, auxiliary information for route guidance, entertainment information, and other data can be written independently by the user and stored as user data 21u. The user data 21 u can be rewritten by operating the operation switch group 7, the touch panel 22 and the remote control terminal 12, or by inputting voice from the microphone 31. Further, data and various information necessary for the operation of the navigation device 100 may be stored as the database 21d.

  The map data 21m and user data 21u can be added / 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, it is good also as a structure downloaded from an external network.

  The nonvolatile memory 9 is constituted by a rewritable semiconductor memory such as an EEPROM or a flash memory, and stores information and data necessary for the operation of the navigation device 100. The nonvolatile memory 9 holds the stored contents even when the accessory switch of the vehicle is turned off, that is, the navigation device 100 is turned off.

  Further, information and data necessary for the operation of the navigation device 100 may be stored in the HDD 21 instead of the nonvolatile memory 9. Furthermore, information and data necessary for the operation of the navigation device 100 may be stored separately in the nonvolatile memory 9 and the HDD 21.

  The display 10 is a liquid crystal display capable of color or monochrome gradation display, and includes a liquid crystal panel 75 (see FIG. 2) made of TFT (Thin Film Transistors) and a backlight (not shown). Consists of. An image is displayed on the liquid crystal panel 75, and the user can view the image by irradiating the image from the back with a backlight.

  The speaker 15 is connected to a known voice synthesis circuit 24 connected to the I / O 84 of the control circuit 8, and the digital voice data stored in the nonvolatile memory 9 or the HDD 21 is converted into an analog voice by the voice synthesis circuit 24 according to a command from the navigation program 21 p. The one converted to is sent. Note that the speech synthesis method includes a recording / editing method in which speech waveforms are stored as they are or after being encoded and connected as necessary.

  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 LAN I / F 26 as information acquisition means of the present invention is an interface circuit for exchanging data with a sensor or other in-vehicle devices 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 16 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 the route guidance processing for displaying the destination route on the display 10 is selected from the menu displayed on the display 10 by the input, the following processing is performed.

  That is, when the user selects a point from a given point or facility search or address search on the map, a registered place set by the user, and sets it as a destination, the position detector 1 determines the current position of the vehicle, Processing for obtaining an optimum guide route from the current position to the destination 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 provides a guidance according to an operation or a message according to an operation state.

  The indicator lamp 25 includes a lamp, an LED, and a drive circuit thereof, and is installed independently of the display device 10. The indicator lamp 25 displays various information such as warnings. The display contents must be notified to the user even when the indicator 10 is not operating, such as a lighting state such as a blinker or a high beam, a seat belt non-wearing warning, and a half-door warning. The lighting state, seat belt wearing state, half-door state, and the like are acquired from other in-vehicle devices via the in-vehicle LAN 27.

  FIG. 2 is a block diagram showing a schematic configuration of a drive circuit included in the display 10. The drive circuit includes a liquid crystal drive power supply circuit 40, a reference potential generation circuit 50, a source driver 60, a scan driver 70, a liquid crystal panel 75, and the like. In FIG. 2, illustration of a controller and a backlight unit that collectively control these components is omitted.

The liquid crystal drive power supply circuit 40 generates a drive power supply voltage V _dcdc supplied to the source driver 60 and a highest reference potential V _{refH applied} to the reference potential generation circuit 50. Further, the reference potential generation circuit 50 uses a plurality of references necessary for generating a grayscale voltage in the source driver 60 based on, for example, resistance division based on the highest reference potential V _refH given from the liquid crystal drive power supply circuit 40. Potentials V _{ref0 to} V _refn are generated.

The source driver 60 uses the drive power supply voltage V _dcdc supplied from the liquid crystal drive power supply circuit 40 as a power supply, and latches the digital image data D _{0 to} D _m input from the control circuit 8. A D / A converter 64 that converts the latched digital image data D _{0 to} D _m into an analog signal using a plurality of reference potentials V _{ref0 to} V _{refn supplied} from the reference potential generation circuit 50, and a D / A converter 64 And an output circuit 62 that buffers the analog signal output from the output signal and outputs the analog signal as a plurality of analog image signals Y _{0 to} Y _k .

Scan driver 70 outputs scan signals X ₀ to X _i having a predetermined period. The liquid crystal panel 75 is composed of a plurality of pixel cells arranged in a matrix. For example, the liquid crystal panel 75 is an active matrix drive liquid crystal display in which on / off of each pixel cell is controlled by a TFT. The liquid crystal panel 75 displays an image determined by the analog image signals Y _{0 to} Y _k of the source driver 60 and the scan signals X _{0 to} X _{i of the} scan driver 70.

Hereinafter, the configuration and operation of the liquid crystal driving power supply circuit 40 will be described. The drive power supply voltage V _dcdc and the highest reference potential V _refH for the source driver 60 need to be determined by the design of the liquid crystal panel 75 and the characteristics of the liquid crystal material, and are necessary for driving the liquid crystal drive power supply circuit 40 itself. It is a voltage different from V _CC . Therefore, in the liquid crystal driving power supply circuit 40, to generate a drive power supply voltage V _dcdc from the power supply voltage V _CC, for efficiency, often, DC / DC converter is used. Here, it is assumed that the drive power supply voltage V _dcdc and the highest reference potential V _refH are higher than the power supply voltage V _cc of the liquid crystal drive power supply circuit 40. Therefore, the liquid crystal drive power supply circuit 40 includes a step-up DC / DC converter 45 and a DC / DC converter control circuit that controls the DC / DC converter 45 in order to generate the drive power supply voltage V _dcdc for the source driver 60. 41.

The DC / DC converter control circuit 41 includes a PWM converter 42, an internal reference voltage generator 43, and an error amplifier 44. The liquid crystal driving power supply circuit 40, an internal reference voltage generator and the resistors R11 and R12 for the internal reference voltage V _REF dividing resistance generated by 43, the drive power supply voltage output from the DC / DC converter 45 V _dcdc Are provided with resistors R13 and R14.

The error amplifying unit 44 calculates the difference between the two voltages using the voltage divided by the resistors R11 and R12 as a non-inverting input and the voltage divided by the resistors R13 and R14 as an inverting input. Further, the PWM converter 42 outputs an oscillation signal V _OUT having a pulse width corresponding to the magnitude of the differential voltage output from the error amplifier 44.

Therefore, when the drive power supply voltage V _dcdc has a target magnitude, the resistance values of the resistors R13 and R14 and the resistors divided by the resistors R11 and R12 are equal to each other. _Is designed, it is possible to realize feedback control in which the difference generated between the actually output drive power supply voltage V _dcdc and the target magnitude is zero. By this feedback control, the liquid crystal drive power supply circuit 40 can stably output the drive power supply voltage V _dcdc that matches the target magnitude.

The liquid crystal drive power supply circuit 40 includes a stabilized power supply circuit 46. The stabilized power supply circuit 46 is, for example, a power supply regulator with 2% accuracy, generates the highest-level reference potential V _refH from _the power supply voltage V _cc of the liquid crystal driving power supply circuit 40.

The highest reference potential V _refH is generated not by the stabilized power supply circuit 46 as shown in FIG. 2 but by using the drive power supply voltage V _dcdc output from the DC / DC converter 45 of the liquid crystal drive power supply circuit 40. It can also be generated by resistance division.

In addition to the above methods, it may be used a configuration for outputting digital image data D ₀ to D _m as a digital image signal without conversion to an analog signal without using the D / A converter 64.

  The pixel cell is composed of a set of RGB (red, green, blue), which are the three primary colors of light, and expresses one color by a combination of RGB colors. Also, if shades are added to each primary color, a number of colors can be expressed by having this darkness level, that is, color tone.

  Further, an organic EL display or a plasma display may be used as the display 10. The organic EL display, for example, arranges organic molecules that emit light in RGB colors in order to form a pixel cell, and changes the gradation of RGB colors by changing the voltage applied to the RGB organic molecules. Thus, the brightness of the display area can be made variable.

  The screen of the plasma display is made up of a collection of three dots of RGB. Each dot has a cell structure sandwiched between two glass substrates having a thickness of about 3 mm. When an electric current is passed from the electrode to the gas sealed in the cell and discharged, plasma is generated. At this time, ultraviolet rays are generated. The ultraviolet rays hit the phosphors of the respective cells and emit visible lights of RGB. When the voltage applied to each dot of RGB is changed, the flowing current is also changed, and the gradation of the RGB color is changed to make the brightness of the display region variable.

  As described above, the configuration of the present invention can also be applied to a so-called self-luminous display such as an organic EL display or a plasma display whose brightness changes depending on the voltage applied to the pixel cell. Even when the screen display is low and the display is dark, if there is information that the user wants to inform quickly, the voltage applied to the pixel cell in the display area of the information is changed to make the color gradation brighter. It is possible to make the display area appear brighter than other areas.

(Brightness adjustment processing 1)
The brightness adjustment processing of the display screen of the display device 10 will be described with reference to FIGS. This process is included in the navigation program 21p and is repeatedly executed together with other programs of the navigation program 21p. First, the brightness information of the display screen of the display 10 stored in a predetermined area of the RAM 83 or the nonvolatile memory 9 is acquired (S1).

  The brightness of the display screen of the display device 10 is set by the user's operation switch group 7, the touch panel 22, the operation of the remote control terminal 12 or the voice input from the microphone 31. Further, the brightness of the display screen of the display 10 also changes when a so-called daytime mode / nighttime mode is switched by operating a light switch (not shown) for turning on / off a vehicle width lamp, a headlamp, and the like. .

When drawing data corresponding to the user's operation is created by the drawing unit 87, the brightness of the display screen of the display device 10 acquired previously with reference to the palette table of FIG. Gradation data is acquired based on the depth information (S2). Then, display is performed based on the acquired gradation data (S3). Drawing data including the data of the gradation is sent from the control circuit 8 to the display unit 10 (the latch circuit 66) as digital image data D ₀ to D _m.

  The pallet table in FIG. 7 represents the relationship between the display type of background, characters, graphics, and the like and the brightness of the display screen of the display 10 in terms of the RBG gradation of the pixel cell that performs the display. It is stored in a memory (not shown) of the drawing unit 87. In the example of FIG. 7, the gradation has 16 levels of 0 to F, and the gradation value increases or decreases according to the brightness level of the display 10. Further, the warning display (blue, red, orange) has a constant gradation regardless of the brightness of the display screen of the display 10.

The warning display, that is, the content displayed at the maximum brightness regardless of the brightness of the display 10 includes one or more of the following.
(1) Information included within a predetermined distance of the current position of the vehicle detected by the position detector 1 among the traffic information and weather information acquired through the transceiver 13.
(2) Contents displayed by the indicator lamp 25.
(3) Information (such as warning display contents on the instrument panel) in which the sensor or other in-vehicle device is estimated to be abnormal among the information of the sensor or other in-vehicle device acquired through the in-vehicle LAN 27.
(4) Information on abnormal operation of the navigation device.
(5) Guidance information such as right and left turn points for route guidance.

(Brightness adjustment process 2)
Another example of the brightness adjustment processing of the display screen of the display device 10 will be described with reference to FIGS. First, the brightness information of the display screen of the display 10 stored in a predetermined area of the RAM 83 is acquired (S11).

  When drawing data corresponding to the user's operation is created in the drawing unit 87, display color information is acquired for each of the background, characters, figures, and the like (S12). The display color information corresponds to, for example, brightness 5 in FIG. 7, and is a gradation for displaying the corresponding display color with the maximum brightness. Display color information is stored in the HDD 21 or a memory (not shown) of the drawing unit 87.

  For each of the background, character, figure, etc. for which display color information has been acquired, the display type is examined. If the display type is a predetermined display type such as a warning display (S13: Yes), the gradation of the acquired display color information ( That is, display is performed based on the maximum brightness (S15).

On the other hand, for example, when it is not a predetermined display type of warning display (S13: No), a coefficient based on the brightness information of the display screen of the display 10 is selected with reference to the coefficient table of FIG. The display gradation is determined by multiplying the gradation of the color information by the coefficient (S14). Then, display is performed based on the determined display gradation (S15). Drawing data including the data of the gradation is sent from the control circuit 8 to the display unit 10 (the latch circuit 66) as digital image data D ₀ to D _m.

  The coefficient table of FIG. 8 defines coefficients rn, gn, and bn of R, B, and G of the pixel cell corresponding to the brightness information of the display screen of the display 10, and is not shown in the HDD 21 or the drawing unit 87. Stored in memory. In the example of FIG. 8, the display color information corresponds to the color R (x, y), G (x, y), and B (x, y) of each pixel when the brightness is 5. Note that (x, y) is a coordinate indicating the position of each pixel on the display screen of the display 10.

  The colors Rn (x, y), Gn (x, y), and Bn (x, y) of each pixel when the brightness of the display screen of the display 10 is n are multiplied by the respective coefficients to obtain R (x, y y) × rn, G (x, y) × gn, and B (x, y) × bn. In the case of a predetermined display type such as a warning display, R (x, y), G (x, y), and B (x, y) are used regardless of the value of brightness n. In FIG. 8, the calculation processing may be performed by defining the coefficient when the brightness is 5 as 1.0.

  9 and 10 are screen display examples on the display 10 when the brightness adjustment processing 1 or 2 of the display screen of the display 10 is used. FIG. 9 shows a display example with the brightest brightness 5, and FIG. 10 shows a display example with the darkest brightness 1. In FIG. 10, the background 10a has a dark gradation corresponding to the brightness, and the character display area 10g is difficult to visually recognize. However, the warning display areas 10b to 10e have the same gradation as that in FIG. Since it is displayed with (brightness 5), it is easy to visually recognize regardless of the brightness of the display 10.

  In the screen display of FIGS. 9 and 10, the warning display areas 10 b to 10 e may be displayed using a known superimpose in which characters and pictures are superimposed on the video.

  9 and 10, the fuel consumption obtained from the fuel consumption obtained from a fuel sensor (not shown) installed in the vehicle and the travel distance obtained from the transition of the current position of the vehicle by the position detector 1 is displayed. Even when route guidance is performed by displaying a map on the display 10, when a guidance message is displayed when reaching a preset guidance point such as a left or right turn, the guidance point on the map is highlighted. Or, when traffic information on the driving route is acquired and displayed superimposed on the map, the brightness is made brighter than the map display (the color gradation is bright) and the user is alerted can do.

  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.

  For example, the present invention is not limited to the display (10) of the vehicle-mounted navigation device (100). For example, the meter display areas 91 to 95 and the navigation display area 96 are simultaneously displayed on the liquid crystal display as shown in FIG. In the in-vehicle display system to be displayed, various displays in the meter display (vehicle speed (92), engine speed (94), water temperature (91), oil temperature, fuel (95), presence / absence of seat belt, parking brake, shift range (93) ) Etc.) can be applied to the brightness adjustment of the present invention. For example, when the remaining amount of fuel falls below a predetermined amount, it is possible to alert the user by setting the gradation of the display color of the fuel meter (95) itself or the fuel warning display to be brighter than other display areas.

  Further, the brightness adjustment of the present invention can be applied to the brightness adjustment between the meter display areas 91 to 95 and the navigation display area 96. According to such an in-vehicle display system, the brightness adjustment of the present invention is applied to a display portion in which the brightness cannot be reduced especially for legal reasons in the meter display areas 91 to 95 even if the brightness of the navigation display area 96 is reduced. This is advantageous because the brightness of the display can be adjusted by the gradation of the display color.

  In the above-described in-vehicle display system, for example, a meter ECU (not shown) that performs display control of information acquired from a sensor attached to a vehicle or other in-vehicle devices, and the in-vehicle navigation device 100 are connected to a network by an in-vehicle LAN 27. The data generated and transmitted by the navigation device 100 is displayed in the navigation display area 96. A method may be used in which data sent from the in-vehicle navigation device 100 is processed by a meter ECU (not shown).

  In addition to an in-vehicle navigation device, meter liquid crystal display, etc., an in-vehicle monitor that displays various travel information, a so-called back monitor that supports driving by displaying the rear of the vehicle when the vehicle is moving backward, and in-vehicle acoustics The brightness adjustment of the present invention can also be applied to a display device such as a video device, and the brightness (gradation of display color) is adjusted according to the priority of the information to be displayed, and the information is reliably transmitted to the user. Is possible.

The block diagram which shows the structure of a vehicle-mounted navigation apparatus. The block diagram which showed schematic structure of the drive circuit contained in a display. The figure for demonstrating the brightness adjustment method by a prior art. The figure for demonstrating the brightness adjustment method by this invention. The flowchart for demonstrating the brightness adjustment process 1. FIG. The flowchart for demonstrating the brightness adjustment process 2. FIG. The figure which shows an example of a pallet table. The figure which shows an example of a coefficient table. The figure which shows the example of a display of the screen in the brightness 5. The figure which shows the example of a display of the screen in the brightness 1. The figure which shows the example of a display of a vehicle-mounted display system.

Explanation of symbols

8 Control circuit (brightness control means, gradation calculation means)
9 Non-volatile memory 10 Display 13 Transceiver (information acquisition means)
21 Hard disk device (gradation storage means)
26 LAN I / F (information acquisition means)
87 Drawing unit 100 Car navigation system

Claims (6)

  An in-vehicle display device comprising brightness control means for adjusting brightness of a screen of the display by adjusting a gradation of a color displayed on the screen of the display.   The in-vehicle display device according to claim 1, wherein the brightness control unit varies the brightness of the display area of the display information according to the type of display information displayed on the screen of the display. Gradation storage means for storing gradation corresponding to the brightness of the display screen and the type of display information;
The in-vehicle display device according to claim 1, wherein the brightness control unit displays the display information with the stored gradation.   The in-vehicle display device according to claim 1, further comprising a gradation calculation unit that calculates a gradation for displaying the display information in accordance with brightness of a screen of the display and a type of the display information.   The in-vehicle display device according to claim 4, wherein the gradation calculation unit multiplies a reference gradation by a predetermined coefficient corresponding to the brightness of the screen of the display and the type of the display information. The in-vehicle display device according to any one of claims 2 to 5, further comprising an information acquisition unit that acquires the display information from an external device.

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