JP5878818B2 - Instrument panel device for vehicle - Google Patents

Description

  The present invention relates to a vehicle instrument panel device, and more particularly to a technique for controlling a vehicle instrument panel device having a plurality of illumination light sources.

  General vehicle instrument panel devices mounted on vehicles such as automobiles are instruments that display the running speed of a vehicle, instruments that display engine rotation speed, and various types that display the state of each part of the vehicle and the presence or absence of an abnormality. The information display part is provided.

  For example, Patent Document 1 is known as a conventional technique related to a vehicle instrument panel device. As disclosed in Patent Document 1, this type of vehicular instrument panel apparatus generally includes a display and further includes a plurality of light sources for illumination.

JP 2010-91546 A

  By the way, in a control circuit inside a vehicle instrument panel device, a power supply voltage of +5 V, which is a general voltage, is often used.

  On the other hand, in order to be able to display various information such as characters, figures and images, a liquid crystal display panel is often mounted on a vehicle instrument panel device. Further, a TFT (Thin Film Transistor) liquid crystal display panel may be employed to enable high quality display. In a TFT liquid crystal display panel, a transistor controls display for each dot of a minute display element constituting a screen. For this reason, a uniform and non-uniform display is possible. In addition, the display response speed is fast and the contrast is high.

  However, when controlling the display contents of the TFT liquid crystal display panel, it is often necessary to use a power supply voltage of + 3.3V. Therefore, when adopting a TFT display panel, a control system using a power supply voltage of +5 V and a control system using a power supply voltage of +3.3 V are mixed in the control circuit of the vehicle instrument panel device. It will be.

  In such a case, it is expected that the control system using the + 5V power supply voltage and the control system using the + 3.3V power supply voltage are controlled by two independent microcomputers.

  On the other hand, in the vehicle instrument panel device, it is necessary to adjust the brightness of illumination according to the preference of the user (driver) or according to the brightness of the surrounding environment. Therefore, in many cases, a rheostat (variable resistor) that can be operated by the user is mounted, and the adjustment state of the rheostat is controlled to reflect the brightness adjustment of the illumination in the vehicle instrument panel device.

  However, when the vehicle instrument panel device is equipped with a plurality of independent microcomputers, the following problems may occur.

  (1) The display contents of the TFT liquid crystal display panel are controlled using the first microcomputer, the backlight brightness is adjusted, and the second microcomputer adjusts the illumination brightness of the entire instrument panel. The case is as follows.

  Since the operation of the first microcomputer and the operation of the second microcomputer are independent, the brightness adjustment of the backlight of the TFT liquid crystal display panel and the brightness adjustment of the entire instrument panel are performed independently of each other. Is called.

  Therefore, when the user adjusts the rheostat for brightness adjustment, the change in the brightness of the backlight and the brightness of the illumination on the entire instrument panel change at different timings or the amount of change in brightness. Differences can occur.

  In particular, when each microcomputer detects the analog level of the signal output from the rheostat by A / D conversion, it is necessary to apply a signal having a different voltage to each microcomputer in accordance with the difference in power supply voltage. There is. Therefore, there is a possibility that a difference occurs in the control amounts of the two microcomputers with respect to a change in the same adjustment amount of the rheostat. As a result, the brightness of the illumination seen by the user flickers, and the user feels uncomfortable.

  (2) The display contents of the TFT liquid crystal display panel are controlled using the first microcomputer, and the backlight brightness of the TFT liquid crystal display panel and the illumination brightness of the entire instrument panel are controlled using the second microcomputer. If you want to adjust:

  In accordance with the adjustment of the rheostat, the second microcomputer can change the brightness of the backlight and the brightness of the entire instrument panel by the same amount at the same timing. However, in this case, since the first microcomputer cannot control the brightness of the backlight, the brightness of the backlight cannot be switched simultaneously or at an appropriate timing when the display content of the TFT liquid crystal display panel is changed. .

  For this reason, for example, when the display content of the TFT liquid crystal display panel is not prepared, only the backlight is turned on first, and the display content may be changed after being illuminated brightly in white over the entire screen. There is. Therefore, when viewed from the user, the screen can be seen to flicker.

  When a plurality of independent microcomputers are used, they can communicate with each other to share the same control information and synchronize the control state. However, a certain amount of time delay occurs when the control information is exchanged by communication, so that the control states of a plurality of microcomputers cannot be completely synchronized. In other words, since the control timing is shifted among the plurality of microcomputers, it is impossible to prevent the above-described flickering of illumination.

  In addition, in order to suppress the flickering of illumination as described above, a high-performance microcomputer with a high processing speed or a dedicated processing circuit must be added, which greatly increases the cost of the apparatus. Was inevitable.

  The present invention has been made in view of the above-described circumstances, and its purpose is to control information displayed on a screen such as a liquid crystal display panel and a plurality of illumination units by a plurality of independent control units. An object of the present invention is to provide a vehicular instrument panel device capable of suppressing unnatural lighting and flickering without incurring a large cost.

In order to achieve the above-described object, a vehicle instrument panel device according to the present invention is characterized by the following (1) to (5).
(1) A light transmissive display capable of controlling display content, a first illumination unit that illuminates the light transmissive display from the back side, and a second that illuminates a location different from the first illumination unit. A vehicle instrument panel device having a lighting section of
A parameter adjustment unit for adjusting a parameter related to the brightness of illumination of the first illumination unit and the second illumination unit;
A first controller that uses power supplied from a first power line and controls at least the second illumination unit according to a parameter determined by the parameter adjustment unit;
A second control unit for controlling at least the display content of the light-transmissive display, using power supplied from a second power supply line in which a voltage different from that of the first power supply line appears;
A first switching circuit that adjusts the brightness of the illumination of the first illumination unit according to a dimming control signal output from the first control unit;
A second switching circuit that switches on / off the illumination of the first illumination unit in accordance with an illumination on / off signal output from the second control unit.
(2) A vehicle instrument panel device having the configuration of (1) above,
The first control unit includes a first dimming control signal for controlling the brightness of the first illumination unit according to the parameter determined by the parameter adjustment unit, and the brightness of the second illumination unit. A second dimming control signal for controlling
The first switching circuit receives the first dimming control signal output from the first control unit, and adjusts the brightness of the illumination of the first illumination unit.
(3) A vehicle instrument panel device having the configuration of (2) above,
The second switching circuit includes a switching element connected to an input of the first switching circuit, and switches an on / off state of the switching element according to the illumination on / off signal.
(4) The vehicle instrument panel device according to any one of (1) to (3) above,
The first control unit and the second control unit are configured by two independent microcomputers that operate asynchronously with each other.
(5) A vehicle instrument panel device having the configuration of (1) above,
The light transmissive display device is a liquid crystal display device incorporating a TFT element.

According to the vehicular instrument panel device having the above configuration (1), the first control unit determines the brightness of the illumination of the first illumination unit and the second illumination unit according to the parameter of the parameter adjustment unit. Can be controlled at the same timing. In addition, the second controller turns on / off the lighting of the first lighting unit, which directly affects the display state of the light transmissive display, in synchronization with a change in display content of the light transmissive display. Can be controlled. Therefore, it is possible to suppress the occurrence of flickering or unnatural brightness changes in the illumination state of the display visible to the user.
According to the vehicular instrument panel device having the above configuration (2), since the first dimming control signal and the second dimming control signal are respectively generated, the brightness of the first illumination unit and the first dimming control signal are generated. The brightness of the illumination unit 2 can be controlled with high accuracy. Further, the illumination on / off signal output from the second control unit does not affect the brightness of the second illumination unit.
According to the vehicular instrument panel device having the configuration (3), it is possible to control the on / off of the illumination of the first illumination unit only by adding a simple circuit.
According to the vehicular instrument panel device having the configuration of (4) above, the control of the illumination light amount according to the parameter of the parameter adjustment unit and the control of the display content of the light transmission type display are controlled by mutually independent control systems. Can be executed.
According to the vehicular instrument panel device having the above configuration (5), the transistor controls the display for each dot of the minute display elements constituting the screen, so that uniform and non-uniform display is possible. In addition, the display response speed is fast and the contrast is high.

  According to the vehicle instrument panel device of the present invention, when controlling information to be displayed on a screen such as a liquid crystal display panel and a plurality of illumination units by a plurality of independent control units, without incurring a large cost, It is possible to suppress unnatural lighting and flickering.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1 is an electric circuit diagram showing a main circuit of a vehicle instrument panel device according to an embodiment. FIG. 2 is a time chart showing an operation example of the circuit shown in FIG.

<Device configuration>
<Overview>
The main circuit of the instrument panel device for a vehicle in this embodiment is shown in FIG.

  The vehicular instrument panel device assumed in the present embodiment includes instruments such as a speedometer and a tachometer that represent the state of the vehicle, as well as a general instrument panel mounted on an automobile, and further travel of the vehicle. Various information such as the distance, the shift position of the transmission, and the presence / absence of abnormality of each part of the vehicle can be displayed.

  The board surface illumination unit 10 included in the circuit shown in FIG. 1 is a light source for illuminating the entire board surface of the vehicle instrument panel device. In addition, the liquid crystal display panel 20 included in the circuit shown in FIG. 1 has a function of displaying numerical values, characters, figures, images, and the like. It can be used to display information such as presence / absence of information as necessary.

  The liquid crystal display panel 20 displays visible information according to the difference in transmission of light that passes through the panel. Therefore, in order to display clear visible information, it is necessary to illuminate from the back side of the panel. The liquid crystal backlight 30 included in the circuit shown in FIG. 1 is a light source for illuminating the liquid crystal display panel 20 from the back side of the panel.

  On the other hand, the brightness of the display displayed by the vehicle instrument panel device needs to be switched according to the difference between day and night or changed according to the preference of the user (driver). The illumination adjusting unit 60 shown in FIG. 1 is a rheostat (variable resistor) arranged at a position where the user can operate, and outputs an illumination reference signal Vr. That is, when the user operates the illumination adjustment unit 60, the illumination reference signal Vr can be changed, and the brightness of the visible information displayed by the vehicle instrument panel device can be adjusted as necessary.

  In order to adjust the brightness of the illumination on the entire panel, the vehicle instrument panel device shown in FIG. 1 adjusts the light emission amount of the panel illumination unit 10 in accordance with the illumination reference signal Vr. In order to adjust the display brightness of the liquid crystal display panel 20, the vehicular instrument panel device shown in FIG. 1 adjusts the light emission amount of the liquid crystal backlight 30 in accordance with the illumination reference signal Vr.

  When the brightness of the display displayed by the vehicle instrument panel device is changed in accordance with the adjustment operation of the illumination adjustment unit 60 by the user, the brightness of the panel illumination unit 10 and the brightness of the liquid crystal backlight 30 are the same timing. It is necessary to change by the same amount. However, if the liquid crystal backlight 30 is turned on in a state where nothing is displayed on the screen of the liquid crystal display panel 20, a screen having no meaning of white as a whole is displayed. Accordingly, the turning on / off of the liquid crystal backlight 30 needs to be synchronized with the display control of the liquid crystal display panel 20.

  In the control system of the vehicle instrument panel apparatus shown in FIG. 1, a control system that uses a power supply voltage of + 5V and a control system that uses a power supply voltage of + 3.3V are mixed. That is, a power supply voltage of +5 V is used for a control system that controls general display. Further, the liquid crystal display panel 20 is a TFT liquid crystal display panel, and it is necessary to use a voltage of +3.3 V in order to control the display contents. Therefore, a control system that uses a power supply voltage of +3.3 V is also provided to perform display control of the liquid crystal display panel 20.

  That is, the main CPU 40 shown in FIG. 1 operates with a power supply voltage of + 5V. Further, the sub CPU 50 operates with a power supply voltage of + 3.3V. The main CPU 40 and the sub CPU 50 are microcomputers that operate independently of each other.

<Description of detailed configuration>
As shown in FIG. 1, the panel illumination unit 10 includes a plurality of light emitting diodes 12 connected in series as a light source. An ignition (IGN) voltage (for example, +12 V) is applied to the positive terminal 11 of the panel illumination unit 10. The terminal 13 on the negative side of the panel illumination unit 10 is connected to the output of the driver circuit 70.

  The liquid crystal backlight 30 includes a plurality of light emitting diodes 32 connected in series as a light source. An ignition (IGN) voltage is applied to the positive electrode terminal 31 of the liquid crystal backlight 30. The negative terminal 33 of the liquid crystal backlight 30 is connected to the output of the driver circuit 90.

  The illumination adjustment unit 60 is connected to a + 5V power supply line and an earth line. Therefore, the voltage of the illumination reference signal Vr can be changed by the user within the range of 0V to + 5V.

  The main CPU 40 realizes a predetermined control function by executing a program incorporated in advance. The main CPU 40 includes an analog signal input port 41, pulse signal output ports 42 and 43, a communication input / output port 44, and a power supply terminal 45.

  DC power necessary for the operation of the main CPU 40 is supplied to the power terminal 45 of the main CPU 40 from a + 5V power line.

  The above-described illumination reference signal Vr is applied to the analog signal input port 41 of the main CPU 40. The main CPU 40 has a function of an A / D converter, and can convert the analog voltage of the illumination reference signal Vr into a digital value and take it in.

  Each of the pulse signal output ports 42 and 43 of the main CPU 40 is used to output a PWM (pulse width modulation) signal. The main CPU 40 has a built-in function for generating a PWM signal. In this embodiment, the pulse width or duty of the PWM signal is changed according to the above-described illumination reference signal Vr. The pulse signal output port 42 outputs a panel illumination PWM signal SG1, and the pulse signal output port 43 outputs a backlight PWM signal SG2.

  The main CPU 40 has a built-in communication function. The communication input / output port 44 of the main CPU 40 is connected to the sub CPU 50.

  The sub CPU 50 realizes a predetermined control function by executing a program incorporated in advance. The sub CPU 50 includes a bus line 51, an output port 52, a communication input / output port 53, and a power supply terminal 54.

  DC power necessary for the operation of the sub CPU 50 is supplied to the power terminal 54 of the sub CPU 50 from the + 3.3V power line.

  Display data SG4 to be displayed on the screen of the liquid crystal display panel 20 is output to the bus line 51 of the sub CPU 50. Since the power supply voltage supplied to the sub CPU 50 is + 3.3V, the voltage of the display data SG4 is switched between high level (H) / low level (L) within the range of 0V to 3.3V. Therefore, the sub CPU 50 can directly drive the liquid crystal display panel 20 operating at +3.3 V using the display data SG4.

  The backlight on / off signal SG3 is output to the output port 52 of the sub CPU 50. The backlight on / off signal SG3 is used to switch on / off the illumination of the liquid crystal backlight 30.

  The sub CPU 50 has a built-in communication function. The communication input / output port 53 of the sub CPU 50 is connected to the main CPU 40.

  The driver circuit 70 includes transistors 71 to 73, a resistor 74, and an input terminal 75. The panel illumination PWM signal SG1 is applied to the input terminal 75 of the driver circuit. The collector of the final stage transistor 73 is connected to the terminal 13 of the panel illumination unit 10.

  When the input terminal 75 of the driver circuit 70 is at a high level (H), the transistors 71 to 73 are turned on, so that the light emitting diode 12 of the panel illumination unit 10 is energized. Further, when the input terminal 75 of the driver circuit 70 is at a low level (L), the transistors 71 to 73 are turned off, so that the light emitting diode 12 of the panel illumination unit 10 is turned off. When a PWM signal appears on the input terminal 75 as the panel illumination PWM signal SG1 at a constant period, the current of the light emitting diode 12, that is, the brightness of the illumination, is determined according to the duty of the PWM signal.

  The driver circuit 90 includes transistors 91 to 93, a resistor 94, and an input terminal 95. The backlight PWM signal SG <b> 2 is applied from the signal line 46 to the input terminal 95 of the driver circuit 90. The collector of the final stage transistor 93 is connected to the terminal 33 of the liquid crystal backlight 30.

  When the input terminal 95 of the driver circuit 90 is at a high level (H), the transistors 91 to 93 are turned on, so that the light emitting diode 32 of the liquid crystal backlight 30 is energized. Further, when the input terminal 95 of the driver circuit 90 is at a low level (L), the transistors 91 to 93 are turned off, so that the light emitting diode 32 of the liquid crystal backlight 30 is turned off.

  When a PWM signal appears in the input terminal 95 as a backlight PWM signal SG2 at a constant period, the current of the light emitting diode 32, that is, the brightness of the illumination, is determined according to the duty of the PWM signal. However, the output of the on / off control circuit 80 is also connected to the input terminal 95 via the signal line 86. Therefore, the state of the on / off control circuit 80 is also reflected in the control of the liquid crystal backlight 30.

  The on / off control circuit 80 includes a transistor 81, a resistor 82, a transistor 83, an input terminal 84, and an output terminal 85. A backlight on / off signal SG3 output from the sub CPU 50 is applied to the input terminal 84 of the on / off control circuit 80.

  When the backlight on / off signal SG3 applied to the input terminal 84 is at a high level (H), the transistor 81 is turned on and the base potential of the transistor 83 is lowered, so that the transistor 83 is turned off. Accordingly, the backlight PWM signal SG2 output from the main CPU 40 is applied to the driver circuit 90 as it is.

  On the other hand, when the backlight on / off signal SG3 applied to the input terminal 84 of the on / off control circuit 80 is at a low level (L), the transistor 81 is turned off and a high potential is applied from the resistor 82 to the base of the transistor 83. The transistor 83 is turned on. Therefore, even when the backlight PWM signal SG2 is output from the main CPU 40, the input terminal 95 of the driver circuit 90 is grounded via the transistor 83, and the backlight is controlled to be in the off state.

<Explanation of device operation>
FIG. 2 shows an example of the operation timing of signals at various parts in the circuit shown in FIG.
In the operation example shown in FIG. 2, the main CPU 40 starts outputting the backlight PWM signal SG2 at time t1, and the sub CPU 50 starts display control of the liquid crystal display panel 20 with the display data SG4 at time t2. It is assumed that the sub CPU 50 switches the backlight from off to on by the backlight on / off signal SG3 at time t3.

  In FIG. 2, the output of the backlight PWM signal SG2 starts at time t1, but at this time, the backlight on / off signal SG3 is still off (L). When the backlight on / off signal SG3 is off, the transistor 83 in the on / off control circuit 80 is turned on, so that the input terminal 95 of the driver circuit 90 is grounded via the transistor 83. Therefore, even if the main CPU 40 outputs the backlight PWM signal SG2, the signal actually applied to the input terminal 95 maintains the low level (L). Therefore, the liquid crystal backlight 30 is kept off.

  In FIG. 2, the sub CPU 50 starts display control of the liquid crystal display panel 20 with the display data SG4 at time t2. Then, at time t3 after the preparation of information to be displayed on the screen of the liquid crystal display panel 20 is completed, the sub CPU 50 switches the backlight on / off signal SG3 from off (L) to on (H).

  When the backlight on / off signal SG3 is turned on, the transistor 83 in the on / off control circuit 80 is turned off, so that the backlight PWM signal SG2 output from the main CPU 40 is directly applied to the input terminal 95 of the driver circuit 90. The Therefore, the light emitting diode 32 of the liquid crystal backlight 30 is energized, and the energization current is determined according to the duty of the PWM signal. That is, dimming control according to the illumination reference signal Vr is performed on the liquid crystal backlight 30.

  As described above, the dimming control of the liquid crystal backlight 30 according to the illumination reference signal Vr can be performed on the main CPU 40 side, and the on / off control of the liquid crystal backlight 30 can be performed on the sub CPU 50 side.

  Therefore, the main CPU 40 controls the panel surface illumination PWM signal SG1 and the backlight PWM signal SG2, so that the light amount of the panel illumination unit 10 and the light amount of the liquid crystal backlight 30 with respect to the change of the illumination reference signal Vr. Can be changed by the same amount at the same time. Therefore, when the user operates the illumination adjustment unit 60, it is possible to eliminate flickering of illumination light that can be seen by the user and uncomfortable illumination.

  Further, since the sub CPU 50 can control the turning on / off of the liquid crystal backlight 30, the liquid crystal backlight 30 is turned on / off at an appropriate timing in accordance with the change of the display content of the liquid crystal display panel 20. Can be switched. For example, as shown in FIG. 2, after the sub CPU 50 starts display control for the liquid crystal display panel 20 (t2) and the display contents are ready (t3), the backlight on / off signal SG3 is switched on. Can do. Thereby, it is possible to avoid the occurrence of flickering on the screen at the start of display of the liquid crystal display panel 20.

  Further, since the operation of the main CPU 40 and the operation of the sub CPU 50 are independent from each other, it is not necessary to employ a high-performance microcomputer in order to reduce the processing time delay, and an increase in device cost can be suppressed.

<Possibility of deformation>
In the vehicular instrument panel device shown in FIG. 1, the illumination reference signal Vr corresponding to the user's operation is generated as an analog signal by the illumination adjustment unit 60 that is a variable resistor. The illumination reference signal Vr may be changed to be supplied from the illumination adjustment unit 60 to the main CPU 40 as a digital signal.

<Supplementary explanation>
(1) The vehicle instrument panel device shown in FIG. 1 includes a light transmissive display (20) capable of controlling display contents, and a first illumination unit (30) for illuminating the light transmissive display from the back side. ) And a second illumination unit (10) that illuminates a portion different from the first illumination unit,
A parameter adjustment unit (60) for adjusting a parameter (Vr) related to the brightness of illumination of the first illumination unit and the second illumination unit;
A first control unit (40) that uses power source power (+5 V) supplied from a first power line and controls at least the second illumination unit according to a parameter determined by the parameter adjustment unit;
A second control unit that controls at least the display content of the light-transmissive display using power supply power (+3.3 V) supplied from a second power supply line in which a voltage different from that of the first power supply line appears. (50),
A first switching circuit (90) for adjusting the brightness of the illumination of the first illumination unit according to a first dimming control signal (SG2) output from the first control unit;
A second switching circuit (80) for switching on / off the illumination of the first illumination unit in accordance with an illumination on / off signal (SG3) output from the second control unit.

(2) In the vehicle instrument panel device shown in FIG.
The first control unit (40) includes a first dimming control signal (SG2) for controlling the brightness of the first illumination unit according to the parameter determined by the parameter adjustment unit, and the second A second dimming control signal (SG1) for controlling the brightness of the illumination unit of
The first switching circuit (90) receives the first dimming control signal output from the first control unit and adjusts the brightness of the illumination of the first illumination unit.

(3) In the vehicle instrument panel device shown in FIG.
The second switching circuit (80) includes a switching element (83) connected to an input (95) of the first switching circuit (90), and the second switching circuit (80) is connected to the switching element according to the illumination on / off signal (SG3). Toggle on / off status.

  (4) In the vehicular instrument panel device shown in FIG. 1, the first control unit (40) and the second control unit (50) are constituted by two independent microcomputers that operate asynchronously with each other. The

(5) In the vehicle instrument panel device shown in FIG.
The light transmission type display (20) is a liquid crystal display with a built-in TFT element.

DESCRIPTION OF SYMBOLS 10 Panel illumination part 11, 13 terminal 12 Light emitting diode 20 Liquid crystal display panel 30 Liquid crystal backlight 31, 33 terminal 32 Light emitting diode 40 Main CPU
41 Analog signal input port 42, 43 Pulse signal output port 44 Input / output port for communication 45 Power supply terminal 46 Signal line 50 Sub CPU
51 Bus Line 52 Output Port 53 Communication Input / Output Port 54 Power Supply Terminal 60 Illumination Adjustment Unit 70 Driver Circuit 71, 72, 73 Transistor 74 Resistor 75 Input Terminal 80 On / Off Control Circuit 81, 83 Transistor 82 Resistor 84 Input Terminal 85 Output Terminal 86 Signal line 90 Driver circuit 91, 92, 93 Transistor 94 Resistor 95 Input terminal SG1 Panel lighting PWM signal SG2 Backlight PWM signal SG3 Backlight on / off signal SG4 Display data Vr Lighting reference signal

Claims (5)

A light transmissive display capable of controlling display contents, a first illumination unit that illuminates the light transmissive display from the back side, and a second illumination unit that illuminates a portion different from the first illumination unit. A vehicle instrument panel device comprising:
A parameter adjustment unit for adjusting a parameter related to the brightness of illumination of the first illumination unit and the second illumination unit;
A first controller that uses power supplied from a first power line and controls at least the second illumination unit according to a parameter determined by the parameter adjustment unit;
A second control unit for controlling at least the display content of the light-transmissive display, using power supplied from a second power supply line in which a voltage different from that of the first power supply line appears;
A first switching circuit that adjusts the brightness of the illumination of the first illumination unit according to a dimming control signal output from the first control unit;
A vehicular instrument panel device comprising: a second switching circuit that switches on / off the illumination of the first illumination unit in accordance with an illumination on / off signal output from the second control unit. The first control unit includes a first dimming control signal for controlling the brightness of the first illumination unit according to the parameter determined by the parameter adjustment unit, and the brightness of the second illumination unit. A second dimming control signal for controlling
The first switching circuit receives the first dimming control signal output from the first control unit, and adjusts the brightness of illumination of the first illumination unit. Item 1. A vehicle instrument panel device according to Item 1. The said 2nd switching circuit has a switching element connected to the input of the said 1st switching circuit, and switches the ON / OFF state of the said switching element according to the said illumination ON / OFF signal. Instrument panel device for vehicles. The vehicle according to any one of claims 1 to 3, wherein the first control unit and the second control unit are configured by two independent microcomputers that operate asynchronously with each other. Instrument panel device. The vehicular instrument panel device according to claim 1, wherein the light transmission type display is a liquid crystal display incorporating a TFT element.

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