JP2020069820A - Display device for vehicle - Google Patents

Abstract

To provide a display device for vehicles capable of suppressing erroneous lighting.SOLUTION: A display device for vehicles 10 controls an on-board light fitting 90 having a high-potential terminal 90H and a low-potential terminal 90L, and displays vehicle information. The display device for vehicles 10 comprises: a high-potential contact 10H which is electrically connected to the high-potential terminal 90H; a low-potential contact 10L which is electrically connected to the low-potential terminal 90L; a changeover unit 50 for switching between a grounding status for grounding the low-potential contact 10L and a blockage status for blocking an electric current without grounding the low-potential contact 10L; a driver 30 for switching between a voltage application status for applying an electric voltage to the high-potential contact 10H and a non-voltage application status for not applying an electric voltage to the high-potential contact 10H; and a light fitting controller 22 which turns on the on-board light fitting 90 by turning the driver 30 into the voltage application status and the changeover unit 50 into the grounding status, and switches off the on-board light fitting 90 by turning the driver 30 into the non-voltage application status and the changeover unit 50 into the blockage status.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle display device.

  2. Description of the Related Art Conventionally, a vehicular display device for lighting a vehicular lamp such as a flasher or a tail lamp is known. For example, a vehicle display device described in Patent Document 1 is a combination meter for displaying vehicle information, and a lighting device corresponding to a lamp having one end connected to a vehicle ground via a battery and the other end connected to the combination meter. And a lamp.

JP, 2002-212172, A

  When electromagnetic noise is applied in the configuration described in Patent Document 1, a potential difference occurs at both ends of the illumination lamp, which may cause the illumination lamp to erroneously light. In particular, in recent years, it has become common to use LEDs (Light Emitting Diodes) as illumination lamps. Unlike a light bulb, an LED is liable to be erroneously turned on even by a minute current flowing due to noise.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicular display device capable of suppressing erroneous lighting.

  In order to achieve the above object, a vehicle display device according to the present invention is a vehicle display device that controls a vehicle-mounted lamp having a high-potential terminal and a low-potential terminal to display vehicle information, wherein the high-potential terminal is A high potential contact electrically connected, a low potential contact electrically connected to the low potential terminal, a grounded state in which the low potential contact is grounded, and a current cutoff without grounding the low potential contact A switching unit that switches between a cutoff state, a driver that switches between a voltage application state in which a voltage is applied to the high potential contact and a non-voltage application state in which no voltage is applied to the high potential contact, and the driver is in the voltage application state. The vehicle-mounted lamp is turned on by setting the switching unit to the grounded state, and the vehicle-mounted lamp is turned off by setting the switching unit to the cutoff state while the driver is in the non-voltage application state. Comprises a lamp control unit that, the.

  According to the present invention, erroneous lighting can be suppressed in the vehicular display device.

1 is a block diagram of a vehicle display device and an on-vehicle lamp according to an embodiment of the present invention. 6 is a timing chart showing a lighting command signal and a grounding command signal according to an embodiment of the present invention.

An embodiment of a vehicle display device for controlling an on-vehicle lamp according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the vehicle display device 10 is a vehicle-mounted meter that displays vehicle information. The vehicle display device 10 performs PWM (Pulse Width Modulation) control of the vehicle-mounted lamp 90 that is provided separately from the vehicle display device 10. The vehicle-mounted lamp 90 is a direction indicator lamp including an LED in this example.

The vehicle display device 10 includes a control unit 20, a display unit 40, a driver 30, a switching unit 50, a high potential contact 10H, and a low potential contact 10L.
The high potential terminal 90H of the vehicle lamp 90 is electrically connected to the high potential contact 10H. The low potential terminal 90L of the vehicle-mounted lamp 90 is electrically connected to the low potential contact 10L.

  The display unit 40 displays vehicle information under the control of the control unit 20. The display unit 40 includes a digital instrument and / or a pointer instrument including a liquid crystal display panel or an organic EL (Electro-Luminescence) display panel.

Under the control of the control unit 20, the driver 30 drives the vehicle-mounted lamp 90 by changing the potential of the high potential contact 10H. That is, the driver 30 is a high side driver.
Specifically, the driver 30 periodically applies the constant voltage from the constant voltage source Va to the vehicle-mounted lamp 90 based on the lighting command signal S1 from the control unit 20. When the driver 30 receives the high potential Hi of the lighting command signal S1, the driver 30 is in a voltage application state in which a constant voltage based on the constant voltage source Va is applied to the vehicle-mounted lamp 90. Further, the driver 30 is in a non-voltage application state in which the constant voltage based on the constant voltage source Va is not applied to the vehicle-mounted lamp 90 when receiving the low potential Lo of the lighting instruction signal S1. The driver 30 is in the non-voltage applied state even in the standby period when the lighting instruction signal S1 is not received.

The switching unit 50 is an NPN transistor, the collector is connected to the low potential contact 10L, the base is connected to the switching port 20L of the control unit 20, and the emitter is grounded. The switching unit 50 includes a resistor R1 connected between the base and the emitter. The resistor R1 suppresses the malfunction of the switching unit 50 by dropping the leak current or noise input to the base to the ground.
The switching unit 50 switches the connection state of the low potential contact 10L under the control of the control unit 20.
Specifically, the switching unit 50 is in a grounded state in which the low potential contact 10L is grounded based on the grounding command signal S2 from the switching port 20L of the control unit 20 and in a cutoff state in which the current is cut off without grounding the low potential contact 10L. To switch. The switching unit 50 is in the grounded state when receiving the high potential Hi of the grounding command signal S2. When the switching unit 50 is grounded, a current flows between the emitter and the collector. Therefore, the current from the high potential contact 10H flows to the ground via the vehicle-mounted lamp 90, the low potential contact 10L, the emitter and the collector of the switching unit 50. Therefore, when the switching unit 50 is in the grounded state and the driver 30 is in the voltage applied state, the vehicle-mounted lamp 90 is turned on.
The switching unit 50 is in the cutoff state when receiving the low potential Lo of the grounding command signal S2. When the switching unit 50 is in the cutoff state, no current flows between the emitter and the collector. Therefore, when the switching unit 50 is in the cutoff state, the in-vehicle lamp 90 does not erroneously light up even if a potential difference occurs at both ends of the in-vehicle lamp 90 due to noise, for example.

The control unit 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The control unit 20 includes a display control unit 21, a lamp control unit 22, an output port 20H, and a switching port 20L as functions.
The display control unit 21 displays vehicle information via the display unit 40 based on a vehicle information signal from an in-vehicle ECU (Electronic Control Unit).

The lamp control unit 22 outputs the lighting command signal S1 to the driver 30 via the output port 20H, and outputs the ground command signal S2 to the switching unit 50 via the switching port 20L.
Specifically, the lamp control unit 22 outputs a lighting command signal S1 to the driver 30 based on an operation signal from a direction indicator light operation unit (not shown). The lighting command signal S1 periodically oscillates between a high potential Hi and a low potential Lo, as shown in FIG. Therefore, the lamp control unit 22 can cause the vehicle-mounted lamp 90 to blink through the driver 30 by outputting the lighting command signal S1 to the driver 30. The lamp control unit 22 performs PWM control for adjusting the brightness of the vehicle lamp 90 based on the on-duty ratio of the lighting command signal S1.

  The lamp control unit 22 outputs the grounding command signal S2 to the switching unit 50 during the period in which the lighting command signal S1 is output, that is, during the period in which the turn signal lamp operating unit (not shown) is operated. On the other hand, the lamp control unit 22 does not output the grounding command signal S2 in a period in which the lighting command signal S1 is not output, that is, in a period in which the turn signal operation unit (not shown) is not operated. The grounding command signal S2 periodically oscillates between the high potential Hi and the low potential Lo, as shown in FIG. The lighting instruction signal S1 and the grounding instruction signal S2 are synchronized. Further, the period T2 of the high potential Hi of the grounding command signal S2 is longer than the period T1 of the high potential Hi of the lighting command signal S1, and the period T1 is set to be included in the period T2. The period T2 is set to a period obtained by adding a margin time Tad before and after the period T1. The margin time Tad is to prevent the grounding command signal S2 from being at the low potential Lo during the period T1 in which the lighting command signal S1 is at the high potential Hi due to a difference in transmission timing of the lighting command signal S1 and the grounding command signal S2. Is set to.

Next, the operation of the vehicle display device 10 and the vehicle-mounted lamp 90 during the period in which the vehicle-mounted lamp 90 blinks will be described with reference to the timing chart of FIG.
At time t1, both the lighting instruction signal S1 and the grounding instruction signal S2 have the high potential Hi. When the lighting command signal S1 has the high potential Hi, the driver 30 applies a constant voltage to the vehicle-mounted lamp 90. Further, when the grounding command signal S2 is at the high potential Hi, the switching unit 50 is grounded. Therefore, at time t1, a current flows through the vehicle-mounted lamp 90 and the vehicle-mounted lamp 90 is turned on.

  At time t2, the grounding command signal S2 is maintained at the high potential Hi, while the lighting command signal S1 is switched from the high potential Hi to the low potential Lo. When the lighting command signal S1 is switched to the low potential Lo, the driver 30 stops applying a constant voltage to the vehicle-mounted lamp 90. Therefore, even if the grounding command signal S2 is at the high potential Hi, in other words, even if the switching unit 50 is in the grounded state, no current flows through the vehicle-mounted lamp 90 and the vehicle-mounted lamp 90 is turned off. The turning-off of the vehicle-mounted lamp 90 is a turning-off period in the blinking period.

At time t3, both the lighting instruction signal S1 and the grounding instruction signal S2 have the low potential Lo. Since the lighting command signal S1 has the low potential Lo, the in-vehicle lamp 90 remains in the off state as at the time t2. Further, when the grounding command signal S2 is at the low potential Lo, the switching unit 50 is in the cutoff state. Therefore, at time t3, even if a potential difference occurs at both ends of the vehicle-mounted lamp 90 due to noise, the vehicle-mounted lamp 90 does not erroneously light but remains in the off state.
In the standby period in which the vehicle-mounted lamp 90 does not blink and is always turned off, the grounding command signal S2 is not output to the switching unit 50 and the switching unit 50 is in the cutoff state. Therefore, even in the standby period, erroneous lighting due to noise is suppressed, as at time t3.

(effect)
As described above, according to the embodiment described above, the following effects can be obtained.

(1) The vehicle display device 10 controls the vehicle-mounted lamp 90 having the high potential terminal 90H and the low potential terminal 90L to display the vehicle information. The vehicle display device 10 is in a grounded state in which the high potential contact 10H electrically connected to the high potential terminal 90H, the low potential contact 10L electrically connected to the low potential terminal 90L, and the low potential contact 10L are grounded. And a switching unit 50 that switches between a cutoff state in which the current is cut off without grounding the low potential contact 10L, a voltage application state in which a voltage is applied to the high potential contact 10H, and a non-voltage application in which no voltage is applied to the high potential contact 10H. The driver 30 that switches between the states, and the vehicle-mounted lamp 90 is turned on by setting the switching unit 50 to the grounded state while keeping the driver 30 in the voltage applied state, and switches the switching unit 50 to the cut-off state while keeping the driver 30 in the non-voltage applied state. The lamp control part 22 which turns off the vehicle-mounted lamp 90 by doing so.
According to this configuration, the switching unit 50 is set to the cutoff state when the driver 30 is in the non-voltage application state. As a result, even if a potential difference occurs at both ends of the vehicle-mounted lamp 90 due to noise, it is possible to prevent the vehicle-mounted lamp 90 from being erroneously turned on if the switching unit 50 is in the cutoff state.

(2) The switching unit 50 is an NPN transistor, the collector is connected to the low potential contact 10L, the base is connected to the lamp control unit 22, and the emitter is grounded.
According to this configuration, since the switching unit 50 is the NPN transistor, it is in the cutoff state when the voltage is not applied to the base. Therefore, the lamp control unit 22 can bring the switching unit 50 into the cutoff state without outputting the grounding command signal S2 to the switching unit 50 during the standby period in which the vehicle-mounted lamp 90 does not blink. Generally, the waiting period of the vehicle-mounted lamp 90 is longer than the blinking period. Therefore, the period during which the lamp control unit 22 outputs the grounding command signal S2 can be shortened, and the processing load and power consumption of the lamp control unit 22 can be reduced.

(3) The lamp control unit 22 outputs the lighting command signal S1 and the grounding command signal S2 that are synchronized with each other to the driver 30 and the switching unit 50.
According to this configuration, since the lighting instruction signal S1 and the grounding instruction signal S2 are synchronized with each other, it is possible to reduce the processing load of the lamp control unit 22 for signal generation.

(4) The lamp control unit 22 sets the period T2 in which the switching unit 50 is in the grounded state to a period in which the driver T30 is in the voltage applied state and includes the period T1 and is increased by the margin time Tad before and after the period T1.
According to this configuration, by setting the margin time Tad, it is possible to prevent the switching unit 50 from being unintentionally turned off during the period T1. Therefore, it is possible to more reliably realize the desired brightness or the desired blinking cycle in the vehicle-mounted lamp 90.

(5) The vehicle-mounted lamp 90 is composed of an LED and is provided at a position away from the vehicle display device 10.
According to this configuration, when the vehicle-mounted lamp 90 is an LED, it is easy to light at a low brightness due to a minute current caused by noise. Even in this case, when the driver 30 is in the non-voltage application state, the switching unit 50 is set to the cutoff state, so that the lighting of the vehicle-mounted lamp 90 is suppressed.

  The present invention is not limited to the above embodiments and drawings. Modifications (including deletion of constituent elements) can be appropriately added without changing the gist of the present invention. An example of the modification will be described below.

(Modification)
In the above-described embodiment, the vehicle-mounted lamp 90 is a direction indicator lamp, but the present invention is not limited to this, and may be a headlight or other lamp related to a high beam or a low beam.

  Although the switching unit 50 is the NPN transistor in the above embodiment, the switching unit is not limited to this and may be another switching element.

  In the above-described embodiment, the period T2 is set to the period in which the margin time Tad is added before and after the period T1, but the period T2 may be the same period as the period T1. In this case, the lighting command signal S1 and the grounding command signal S2 have the same waveform, and the processing load on the signal generation of the lamp control unit 22 can be reduced.

  Although the vehicle-mounted lamp 90 is an LED in the above embodiment, it may be a light bulb.

10 Vehicle display device 10H High potential contact 10L Low potential contact 20 Control unit 20H Output port 20L Switching port 21 Display control unit 22 Lamp control unit 30 Driver 40 Display unit 50 Switching unit 90 In-vehicle lamp 90H High potential terminal 90L Low potential terminal S1 Lighting command signal S2 Grounding command signal Tad Allowance time

Claims (3)

A vehicle display device for controlling a vehicle-mounted lamp having a high-potential terminal and a low-potential terminal to display vehicle information,
A high potential contact electrically connected to the high potential terminal,
A low potential contact electrically connected to the low potential terminal,
A switching unit that switches between a grounding state in which the low potential contact is grounded and a blocking state in which a current is blocked without grounding the low potential contact,
A driver that switches between a voltage application state in which a voltage is applied to the high potential contact and a non-voltage application state in which a voltage is not applied to the high potential contact,
The vehicle-mounted lamp is turned on by setting the switching unit to the grounded state while the driver is in the voltage applied state, and the vehicle-mounted by setting the switching unit to the cut-off state while keeping the driver in the non-voltage applied state. A lamp control unit for turning off the lamp,
Vehicle display device. The switching unit is an NPN transistor, a collector is connected to the low potential contact, a base is connected to the lamp control unit, and an emitter is grounded.
The vehicle display device according to claim 1. The lamp control unit outputs command signals synchronized with each other to the driver and the switching unit,
The vehicle display device according to claim 1.