JP2012240631A - Display device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device for a vehicle, capable of preventing abnormal display of vehicle information by using a discharge circuit when power supply is stopped.SOLUTION: The display device for a vehicle includes: a display means 1 for displaying vehicle information; a drive circuit 2 for giving drive signals to the display means 1; a control means 3 for urging desired display to the display means 1 by controlling the drive circuit 2; a power source circuit 4 for generating a driving voltage of the control means 3 by utilizing the power source of an on-board battery B; a capacitor 5 connected to the drive circuit 2 for smoothing the bias circuit of the display means 1; and a discharge circuit 6 connected to the drive circuit 2 and provided so as to discharge the charges of the capacitor 5. The drive circuit 2 includes: a reset circuit 21 for resetting the drive signals 2 on the basis of reset signals from the control means 3; and a boosting circuit 22 for boosting the drive voltage from the power source circuit 4 in order to generate the drive signals.

Description

  The present invention relates to a display device for a vehicle, and particularly to a display device for a vehicle that displays using a display panel.

  2. Description of the Related Art Conventionally, as a vehicle display device, for example, there is a vehicle instrument disclosed in Patent Document 1, a pointer-type display unit including a speedometer, a liquid crystal or an organic display for displaying various information such as a travel distance and an outside temperature. There is a composite instrument provided with a display panel unit using EL.

  In addition, the liquid crystal display devices mounted on these instruments are generally liquid crystals that display information such as specific figures and characters by selectively applying an electric field to a predetermined portion of a pair of transparent substrates filled with liquid crystal in the middle. A liquid crystal display device with a built-in display panel is often used as a display device for computers, mobile phones, and the like. Such a liquid crystal display device has a panel driving IC chip for driving the liquid crystal display panel. ing.

  In addition, a bias voltage generating circuit is incorporated in the panel driving IC chip in response to a demand for low power consumption, and the liquid crystal display device having such a liquid crystal display panel driving IC chip generates a bias voltage. A voltage is held in a bias circuit smoothing capacitor by a bias generated by the circuit.

JP 2003-76294 A

  However, in the liquid crystal display device, the bias voltage charge held in the bias circuit smoothing capacitor may flow toward the liquid crystal display panel when the power source of the liquid crystal display device is turned off. As a result, a part of the display of the liquid crystal display panel may be abnormally displayed, which is a problem.

  In particular, in a vehicle display device, a case where a predetermined power supply voltage cannot be obtained due to deterioration of an on-vehicle battery or a load state of an electrical component is assumed. Therefore, abnormal vehicle information can be obtained even in various power supply states. There was a room for improvement.

  Accordingly, an object of the present invention is made by paying attention to the above-described problems, and for a vehicle that can prevent display of abnormal vehicle information by using a discharge circuit when power supply is stopped. It is to provide a display device.

  The vehicle display device of the present invention includes a display means for displaying vehicle information, a drive circuit for supplying a drive signal to the display means, and a control means for prompting the display means for a desired display by controlling the drive circuit. A power supply circuit that generates a drive voltage of the control means using a power supply of the on-vehicle battery, a capacitor connected to the drive circuit for smoothing a bias circuit of the display means, and a capacitor connected to the drive circuit A discharge circuit provided so as to be able to discharge the electric charge of the control circuit, wherein the drive circuit resets the drive circuit based on a reset signal from the control means, and a power supply voltage for generating the drive signal. A booster circuit for boosting, and when the drive voltage from the power supply circuit to the control means is interrupted, the reset circuit is used to drive the drive circuit. It resets the said discharge circuit vehicular display apparatus characterized by discharging the electric charge of the capacitor used.

  The power supply circuit inputs power from the in-vehicle battery via a start switch of a vehicle.

  Further, it is characterized by comprising switch means for switching whether or not to supply the drive voltage generated by the power supply circuit to the drive circuit based on a control signal from the control means.

  Further, the wiring between the reset circuit and the control means is connected to a reset unit composed of a pull-down resistor element having one end grounded.

  Further, the discharge circuit is characterized in that it includes a discharge section that is made up of a pull-down resistor element that branches to a wiring for supplying power to the booster circuit and is grounded at one end.

  The present invention relates to a display device for a vehicle including a display panel that displays vehicle information on a screen, and when the power supply is stopped, the use of a discharge circuit can prevent abnormal vehicle information from being displayed.

1 is a block diagram showing a circuit configuration of an embodiment of the present invention.

  Hereinafter, an embodiment applied to a vehicle instrument will be described as an embodiment of the present invention with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an electrical configuration of a vehicle meter according to the invention. A display means 1, a drive circuit 2, a control means 3, a power supply circuit 4, a capacitor 5, and a discharge circuit 6 are provided. It is mounted on a circuit board provided in the housing of the vehicle instrument.

  As the display means 1, for example, a display panel for displaying various information that changes every moment can be applied to a user who is driving a vehicle, and a display panel using liquid crystal or organic EL is preferable. In this case, the display means 1 uses a TFT-type liquid crystal display panel provided with a drive driver. Based on the control and drive of the control means 3 and the drive circuit 2, various information relating to the vehicle, for example, the traveling speed of the vehicle. In addition, the vehicle information such as the remaining fuel amount, the fuel consumption, the indicator such as the accumulated travel distance, the gear position, and the alarm is displayed and output in a desired image.

  Further, the display means 1 can display a measured value calculated by calculation by the control means 3 or calculation processing by a control circuit other than the vehicle meter using a drive signal from the drive circuit 2, In the instrument panel, it is provided so that the vehicle user can visually recognize the display of the vehicle information. In this case, the display unit 1 is connected to the drive circuit 2 via a circuit board or wiring on which a light emitting diode that is a backlight (not shown) is mounted.

  Further, the display means 1 may be used for display applications such as opening / closing state of a vehicle door, time, vehicle peripheral video (back monitor, etc.), television broadcast image, character information by wireless communication, etc. by switching screens. It is done.

  The drive circuit 2 generates and outputs a drive signal for driving the display means 1 based on a control signal generated from the control means 3, and a drive driver IC can be applied to the liquid crystal display panel. In addition, the drive circuit 2 includes a reset circuit 21 that resets the drive circuit 2 based on a reset signal from the control unit 3 and a booster circuit 22 that boosts the power supply voltage to generate the drive signal.

  In addition, the wiring between the reset circuit 21 and the control means 3 is connected to a reset unit 21a composed of a pull-down resistance element whose one end is grounded. The reset circuit 21 receives a reset signal from the control means 3 In this case, or when there is no signal, the drive circuit 2 is reset. Therefore, when the control means 3 does not operate, the drive circuit 2 is reset by grounding the reset unit 21a. In this case, when the input to the reset circuit 21 is a 0V signal, it is recognized as a reset signal and reset processing is performed. When other voltage (for example, 5V) is input, the normal operation state is maintained. Designed to be

  Further, the booster circuit 22 inputs the boosting power generated by the control from the control means 3 using the power supply from the in-vehicle battery B, boosts the voltage using the capacitor 5, and is necessary for the display of the display means 1. Generate voltage.

  The control means 3 can be a microcomputer connected to the drive circuit 2 via a signal line, and the information from various sensors mounted on the vehicle is transmitted via a communication cable using the power from the power supply circuit 4 as a drive source. An input process is performed based on the vehicle information from the vehicle side and a predetermined program. Further, the control means 3 is configured to generate a control signal for controlling the display means 1 by this arithmetic processing and output it to the drive circuit 2.

  In addition to the display process for generating and outputting a control signal for displaying the vehicle information on the display means 1, the control means 3 performs a switch process for switching the power supply to the drive circuit 2 via the switch circuit 7. The storage unit stores each program for performing reset processing of the drive circuit 2 and the calculation result.

  The power supply circuit 4 generates drive voltages for the control means 3 and the drive circuit 2 using the power supply of the in-vehicle battery B. In this case, the power supply circuit 4 inputs a power supply voltage (for example, 8 to 14 V) to the vehicle-mounted battery B via the vehicle start switch S or the power fuse F including an ignition switch, and a desired voltage (for example, for example) 5V) and output. The power supply circuit 4 is connected to the drive circuit 2 via the switch circuit 7.

  The capacitor 5 is connected to the booster circuit 22 of the drive circuit 2 for smoothing the bias circuit of the display means 1 and is used to hold the bias voltage generated by the booster circuit 22.

  The discharge circuit 6 branches to a wiring for supplying power to the booster circuit 22 and is provided with a discharge unit composed of a pull-down resistor element having one end grounded. When the driving circuit 2 is reset, the discharge circuit 6 can flow the electric charge of the capacitor 5 boosted and held by the booster circuit 22 to the ground side without flowing to the display means 1 side. The influence of the display on the display means 1 due to electric charges can be prevented.

  The switch circuit 7 can be a transistor or the like, and can switch whether or not the power supply from the power supply circuit 4 is supplied to the drive circuit 2 based on a signal from the control means 3. After the control means 3 is activated, power is supplied to the drive circuit 2 and the power supply to the drive circuit 2 is stopped before the control means 3 stops.

  Such a vehicle meter includes a display unit 1 that displays vehicle information, a drive circuit 2 that supplies a drive signal to the display unit 1, and a control that prompts the display unit 1 to display a desired display by controlling the drive circuit 2. Means 3, a power supply circuit 4 for generating a drive voltage for the control means 3 using the power supply of the vehicle battery B, a capacitor 5 connected to the drive circuit 2 for smoothing the bias circuit of the display means 1, and a drive circuit 2 And a discharge circuit 6 provided so as to be capable of discharging the electric charge of the capacitor 5. The drive circuit 2 resets the drive circuit 2 based on a reset signal from the control means 3, and the drive And a booster circuit 22 that boosts the drive voltage from the power supply circuit 4 to generate a signal. When the drive voltage from the power supply circuit 4 to the control means 3 is interrupted, the reset circuit 21 is used. Resets the driving circuit 2 Te, to discharge the capacitor 5 using the discharging circuit 6.

  Therefore, for example, when the in-vehicle battery B is removed or when the predetermined voltage cannot be supplied due to deterioration, the electric charge of the bias voltage held in the capacitor 5 is discharged when the power supply is unexpectedly turned off. Can do. By operating this discharge based on a reset signal applied by the reset unit 21a, it is possible to discharge without flowing the charge of the bias voltage of the capacitor 5 to the display means 1. Therefore, abnormal display by the display means 1 can be prevented.

  The vehicle display device of the present invention has been described by way of example in the configuration of the embodiment described above, but the present invention is not limited to this, and the gist of the present invention is also achieved in other configurations. It goes without saying that various improvements and design changes can be made without departing from the scope.

  The present invention can be applied as, for example, a display device for a vehicle mounted on a moving body including an automobile, a motorcycle, an agricultural machine, or a construction machine.

1 Display means
2 Drive circuit 21 Reset circuit 22 Booster circuit 3 Control means 4 Power supply circuit 5 Capacitor 6 Discharge circuit

Claims (5)

Display means for displaying vehicle information;
A drive circuit for supplying a drive signal to the display means;
Control means for urging the display means to display a desired display by controlling the drive circuit;
A power supply circuit that generates a drive voltage of the control means using a power supply of the vehicle battery;
A capacitor connected to the drive circuit for smoothing the bias circuit of the display means;
A discharge circuit connected to the drive circuit and provided to be able to discharge the electric charge of the capacitor,
The drive circuit includes a reset circuit that resets the drive circuit based on a reset signal from the control unit, and a booster circuit that boosts a power supply voltage to generate the drive signal.
When the drive voltage from the power supply circuit to the control means is interrupted, the drive circuit is reset using the reset circuit, and the electric charge of the capacitor is discharged using the discharge circuit. Display device.   The vehicle display device according to claim 1, wherein the power supply circuit inputs power from the in-vehicle battery via a start switch of the vehicle.   The switch means for switching whether to supply the drive voltage generated by the power supply circuit to the drive circuit based on a control signal from the control means is provided. The vehicle display device described.   The vehicle according to any one of claims 1 to 3, wherein a reset unit including a pull-down resistor element having one end grounded is connected to a wiring between the reset circuit and the control unit. Display device.   5. The discharge circuit according to claim 1, wherein the discharge circuit is provided with a discharge portion that is made up of a pull-down resistor element branched to a wiring for supplying power to the booster circuit and grounded at one end. The vehicle display device described in 1.

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