Vehicle lighting devices

Abstract

The present invention provides a vehicle-mounted light-emitting device that can monitor for malfunctions such as broken wires in the light source even when the power supply voltage is low. [Solution] The vehicle light-emitting device 2 includes a control unit 11 that controls a drive device 4 for driving a light source 3 by constant current control, the control unit monitors the power supply voltage input to the drive device, determines that there is a problem with the drive device if the power supply voltage is abnormal, sets the control mode for controlling the drive device to normal mode if the power supply voltage is normal, sets the control mode to safe mode which controls at a lower voltage than the normal mode if the power supply voltage drops, monitors the drive voltage output from the drive device to the light source according to the control mode, determines whether the drive voltage is within the normal voltage range, determines that there is a problem with the light source if the drive voltage is outside the normal voltage range and outputs a signal indicating the problem.

Description

Technical Field

[0001] The present invention relates to a vehicle lighting device capable of monitoring a disconnection of a light source.

Background Art

[0002] Patent Document 1 describes a light-emitting diode driving device that detects a short-circuit fault occurring in a light source using a light-emitting diode. According to the technique described in Patent Document 1, it includes a control unit that causes the light-emitting diode to emit light based on constant current control. This control unit sets a predetermined reference current value for supplying power to the light source, sets a voltage threshold for determining a short-circuit fault of the light source, compares the detected voltage value of the direct current voltage of the light source with the threshold value, and when detecting a decrease in the direct current voltage, reduces the predetermined reference current value, reduces the threshold value, and is configured to protect the light-emitting diode driving device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, in order to realize a blind spot monitor in a vehicle, an indicator using a light-emitting diode such as an outer mirror indicator is provided.This indicator is driven based on a constant current and its failure state is monitored. To monitor the failure state of the indicator, the voltage is monitored. When performing voltage monitoring in a circuit based on a constant current, it is necessary to ensure a sufficient power supply voltage for the driving circuit. However, according to the technique described in Patent Document 1, it monitors a direct current, and when a decrease in the power supply voltage occurs, the voltage cannot be correctly determined. According to the technique described in Patent Document 1, it may be difficult to monitor the voltage to detect whether the light source is disconnected.

[0005] The present invention aims to provide a vehicle light-emitting device that can monitor for malfunctions such as disconnections in the light source even when the power supply voltage is low. [Means for solving the problem]

[0006] One aspect of the present invention is a vehicle light-emitting device 2 comprising a control unit 11 that controls a drive device 4 for driving a light source 3 by constant current control, wherein the control unit monitors the power supply voltage input to the drive device, determines that there is a problem with the drive device if the power supply voltage is abnormal, sets the control mode for controlling the drive device to normal mode if the power supply voltage is normal, sets the control mode to safe mode which controls at a lower voltage than the normal mode if the power supply voltage drops, monitors the drive voltage output from the drive device to the light source according to the control mode, determines whether the drive voltage is within the normal voltage range, determines that there is a problem with the light source if the drive voltage is outside the normal voltage range and outputs a signal indicating the problem. That is the case. [Effects of the Invention]

[0007] According to the present invention, fault monitoring, such as disconnection of a light source, can be performed even when the power supply voltage is low. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing a vehicle equipped with a vehicle light-emitting device according to an embodiment of the present invention. [Figure 2] This diagram shows the relationship between power supply voltage, drive voltage, drive current, and fault condition. [Figure 3] This figure shows the method for determining the fault state in normal mode. [Figure 4] This diagram shows the method for determining the fault state in safe mode. [Figure 5] This flowchart shows the processing flow of a fault diagnosis method performed in a vehicle's light-emitting device. [Modes for carrying out the invention]

[0009] As shown in Figure 1, the vehicle 1 is equipped with a vehicle light-emitting device 2 capable of displaying an indicator. The vehicle light-emitting device 2 comprises a light source 3 having an illumination function. The vehicle light-emitting device 2 is applied to a predetermined indicator device, such as a blind spot monitor, based on the illumination of the light source 3. The vehicle light-emitting device 2 is configured to be able to determine a malfunction such as a disconnection of the light source 3. The light source 3 is composed of an illumination-emitting element such as a light-emitting diode. The light source 3 may be composed of one or more light-emitting diodes.

[0010] A drive unit 4, which supplies driving power, is electrically connected to the light source 3. A power supply unit 5, which supplies power, is connected to the drive unit 4. The power supply unit 5 supplies power to the drive unit 4 based on a preset power supply voltage. In normal conditions, the power supply unit 5 supplies power based on a power supply voltage within the set range. If the power supply unit 5 is not in normal conditions, it supplies power based on a power supply voltage lower than the set range.

[0011] The drive unit 4 is configured to supply drive power to the light source 3 based on a drive voltage and drive current based on the power supply voltage input from the power supply unit 5. In normal mode, as described later, the drive unit 4 supplies drive power to the light source 3 based on a first drive voltage and a first drive current. In safe mode, as described later, the drive unit 4 supplies drive power to the light source 3 based on a second drive voltage and a second drive current. A detection unit 6 for monitoring the operating status is connected to the power supply unit 5 and the drive unit 4.

[0012] The detection unit 6 detects the power supply voltage input from the power supply unit 5 to the drive unit 4. The detection unit 6 also detects the drive voltage output from the drive unit 4 to the light source 3. The detection unit 6 is composed of, for example, a circuit capable of detecting voltage. The detected value detected by the detection unit 6 is monitored by the control unit 11, which will be described later.

[0013] The vehicle light-emitting device 2 is equipped with a control unit 11 that performs calculations and controls the device. The control unit 11 controls a drive unit 4 for driving the light source 3 by constant current control. The control unit 11 is configured to be able to determine the failure state of the drive unit 4. The vehicle light-emitting device 2 is equipped with a storage unit 12 that can store data and programs necessary for control and calculations. The control unit 11 stores the detected value detected by the detection unit 6 in the storage unit 12.

[0014] The control unit 11 is comprised of at least one hardware processor, such as a CPU (Central Processing Unit). The control unit 11 may be implemented by hardware (including circuitry) such as an LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), or GPU (Graphics Processing Unit), or it may be implemented through the collaboration of software and hardware.

[0015] The storage unit 12 is composed of non-temporary storage media such as a hard disk drive (HDD) or a solid-state disk (SSD). The program may be pre-stored in the storage unit 12, or it may be stored in a removable storage medium such as a DVD, CD-ROM, or memory medium. The program may also be installed in the storage unit 12 by connecting an external storage medium.

[0016] The vehicle light-emitting device 2 includes a notification unit 13 that outputs information to the user. The notification unit 13 is composed of, for example, a display device capable of displaying information related to the notification content. The display device is, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display. The notification unit 13 may also be composed of a speaker that outputs information related to the notification content based on sound. The notification unit 13 may also be composed of an indicator that outputs information related to the notification content based on light emission.

[0017] Generally, outer mirror indicators have clearly defined brightness levels to ensure visibility to the user. Outer mirror indicators are configured to allow users to adjust the brightness according to their preferences during the day or night. Therefore, it is desirable for outer mirror indicators to be configured with a constant current circuit that allows for fine-tuning of brightness by current. However, if the power supply voltage to the constant current circuit is lower than the preset drive voltage, it becomes difficult to correctly detect a break in the light source based on the voltage.

[0018] Therefore, constant current circuits require monitoring the current value and determining whether a light source is broken based on the amount of current flowing. Consequently, monitoring for a broken light source in a constant current circuit requires two monitoring circuits: one for voltage monitoring and one for current monitoring, which increases the number of components. In contrast, the control unit 11 is configured to monitor the voltage between the power supply unit 5 and the drive unit 4 detected by the detection unit 6, and to determine whether or not a malfunction has occurred in the vehicle light-emitting device 2.

[0019] Figure 2 shows the relationship between the power supply voltage and the fault states occurring in the vehicle lighting device 2. For the power supply voltage VA supplied by the power supply unit 5, a normal voltage VA1 which is the determination threshold value for the normal state and a reduced voltage VA2 which is the determination threshold value for the abnormal state are set. The control unit 11 sets the control mode according to the state of the power supply voltage VA. The control mode includes a normal mode in the normal state where the power supply voltage VA is equal to or higher than the normal voltage VA1, and a safe mode in the range where the power supply voltage is less than the normal voltage VA1 and equal to or higher than the reduced voltage VA2.

[0020] The control unit 11 sets a normal voltage range between the upper limit and the lower limit of the determination threshold for the driving voltage VB according to the control mode. When a power supply voltage equal to or higher than the normal voltage VA1 is supplied, the control unit 11 sets the control mode to the normal mode. In the normal mode, the control unit 11 sets a normal voltage range between the upper limit value VB1 and the lower limit value VB3 of the determination threshold. In the normal mode, the control unit 11 sets an abnormal voltage range in the range exceeding the upper limit value VB1 of the determination threshold. In a normal state, the driving voltage VB is within the normal voltage range. When an abnormality such as a disconnection occurs, the load of the light source 3 disappears, so that the driving voltage VB is in an abnormal voltage range exceeding the normal voltage range. In the normal mode, the control unit 11 causes the driving device 4 to supply driving power based on the first driving voltage VP1 to the light source 3.

[0021] In the safe mode, the control unit 11 sets a normal voltage range between the upper limit value VB2 of the determination threshold which is lower than VB1 and the lower limit value VB3 of the determination threshold. In the safe mode, the control unit 设定 an abnormal voltage range in the range exceeding the upper limit value VB of the determination threshold. In the safe mode, the control unit 11 causes the driving device 4 to supply driving power based on the second driving voltage VP2 to the light source

[0022] The drive unit 4 supplies a constant drive current C to the light source 3. The drive current C is adjustable by the user in normal mode. In normal mode, if the user's initial setting is set to "bright", the drive current C is set to a first drive current C1 so that the amount of light emitted from the light source 3 becomes brighter. In normal mode, the control unit 11 causes the drive unit 4 to supply a first drive power to the light source 3 based on a first drive voltage VP1 and a first drive current C1. In safe mode, if the user's initial setting is set to "bright", the drive current C is set to a second drive current C2 which is lower than the first drive current C1 so that the amount of light emitted from the light source 3 becomes dimmer. In safe mode, the control unit 11 causes the drive unit 4 to supply a second drive power to the light source 3 based on a second drive voltage VP2 and a second drive current C2.

[0023] The control unit 11 monitors the power supply voltage VA input to the drive unit 4 and the drive voltage VB output from the drive unit 4 to the light source 3 based on the detected value detected by the detection unit 6. The control unit 11 determines that the power supply voltage VA is normal if it is equal to or greater than the normal voltage VA1. If the power supply voltage VA is normal, the control unit 11 sets the control mode for controlling the drive unit 4 to normal mode.

[0024] Figure 3 shows a method for diagnosing faults such as disconnections in the drive unit 4 and light source 3 in normal mode. The control unit 11 sets the control mode to normal mode when the power supply voltage is equal to or greater than the normal voltage VA1. If the user customization is set to "bright", the control unit 11 causes the drive unit 4 to supply the light source 3 with a first drive voltage VP1 and a first drive power based on the first drive current C1.

[0025] The control unit 11 determines whether the first drive voltage VP1 is within the normal voltage range between the upper limit VB1 and the lower limit VB3 of the determination threshold. If the first drive voltage VP1 is within the normal voltage range, the control unit 11 determines that the drive unit 4 is functioning correctly. If the first drive voltage VP1 is outside the normal voltage range and in an abnormal voltage range, the control unit 11 determines that there is a problem with the light source 3. The control unit 11 generates a signal indicating the problem and outputs it to the notification unit 13. The control unit 11 causes the notification unit 13 to output information regarding the notification content indicating that there is a problem with the light source 3. The control unit 11 stops the power supply unit 5 and / or the drive unit 4 and stops the function of the vehicle light-emitting device 2.

[0026] Figure 4 shows a method for diagnosing faults such as disconnections in the drive unit 4 and light source 3 in safe mode. The control unit 11 sets the control mode to safe mode when the power supply voltage is less than the normal voltage VA1 and is a low voltage VA2. The control unit 11 sets the light output of the light source 3 to "dim" and causes the drive unit 4 to supply the first drive power based on the second drive voltage VP2 and the second drive current C2 to the light source 3.

[0027] The control unit 11 determines whether the second drive voltage VP2 is within the normal voltage range between the upper limit VB2 and the lower limit VB3 of the determination threshold. If the second drive voltage VP2 is within the normal voltage range, the control unit 11 determines that the light source 3 is normal. If the second drive voltage VP2 is outside the normal voltage range and is in an abnormal voltage range, the control unit 11 determines that there is an abnormality in the light source 3. The control unit 11 generates a signal indicating an abnormality and outputs it to the notification unit 13. The control unit 11 causes the notification unit 13 to output information regarding the notification content indicating that an abnormality has occurred in the light source 3. The control unit 11 stops the power supply unit 5 and / or the drive unit 4 and stops the function of the vehicle light source 2.

[0028] Figure 5 shows the processing flow of the fault diagnosis method performed in the vehicle light-emitting device 2. The fault diagnosis method is performed based on a computer program that can be installed on the computer mounted in the vehicle light-emitting device 2. The computer program causes the control unit 11 of the vehicle light-emitting device 2 to perform the following processing.

[0029] The control unit 11 determines whether the power supply voltage VA is equal to or greater than the normal voltage VA1 based on the detected value detected by the detection unit 6 (S100). If the control unit 11 determines that the power supply voltage VA is equal to or greater than the normal voltage, it sets the control mode to normal mode (S102). In normal mode, the control unit 11 determines whether the drive voltage VB is in the abnormal voltage range (S104). If the drive voltage VB is not in the abnormal voltage range (S104: No) and is in the normal voltage range, the control unit 11 determines that the light source 3 is normal (S106). The control unit 11 returns to processing S100.

[0030] If the control unit 11 determines that the drive voltage VB is within the abnormal voltage range (S104: Yes), it determines that the light source 3 is disconnected (S108). The control unit 11 stops the drive unit 4 and / or the power supply unit 5 and stops the function of the vehicle light-emitting device 2 (S110). The control unit 11 outputs a signal indicating that an abnormality has occurred in the light source 3 and causes the notification unit 13 to output information regarding the notification content indicating the abnormality (S111).

[0031] If the control unit 11 determines in S100 that the power supply voltage VA is below the normal voltage, it determines whether the power supply voltage VA is equal to or greater than the undervoltage VA2 (S112). If the control unit 11 determines that the power supply voltage VA is equal to or greater than the undervoltage VA2, it sets the control mode to safe mode (S114). The control unit 11 determines whether the drive voltage VB is within the abnormal voltage range (S116). If the control unit 11 determines that the drive voltage VB is within the abnormal voltage range (S116: Yes), it determines that the light source 3 is disconnected (S108). If the control unit 11 determines that the drive voltage VB is not within the abnormal voltage range (S116: No) and is within the normal voltage range, it determines that the light source 3 is normal (S106). The control unit 11 returns to processing S100.

[0032] If the control unit 11 determines in S112 that the power supply voltage VA is less than the low voltage VA2 (S112: No), it determines that the drive unit 4 is abnormal (S118). The control unit 11 stops the drive unit 4 and / or the power supply unit 5 and stops the function of the vehicle light-emitting device 2 (S110).

[0033] As described above, the vehicle light-emitting device 2 can monitor for malfunctions such as disconnections in the light source 3 even when the power supply voltage is low. The vehicle light-emitting device 2 can monitor for malfunctions such as disconnections in the light source 3 by monitoring the power supply voltage input to the drive unit 4 and the drive voltage output from the drive unit 4. The vehicle light-emitting device 2 can simplify the device configuration by performing fault monitoring by monitoring the voltage without providing a circuit to monitor the constant current drive current output from the drive unit 4. [Explanation of Symbols]

[0034] 1 Vehicle, 2 Vehicle light-emitting device, 3 Light source, 4 Drive unit, 5 Power supply unit, 6 Detection unit, 11 Control unit, 12 Memory unit, 13 Notification unit, C Drive current, C1 First drive current, C2 Second drive current, EL Organic, VA Power supply voltage, VA1 Normal voltage, VA2 Undervoltage, VB Drive voltage, VB1 Upper limit, VB2 Upper limit, VB3 Lower limit, VP1 First drive voltage, VP2 Second drive voltage

Claims

[Claim 1] It includes a control unit that controls a drive device for driving a light source by constant current control, The control unit, The power supply voltage input to the aforementioned drive device is monitored, If the power supply voltage is abnormal, it is determined that there is a malfunction in the drive device. If the power supply voltage is normal, the control mode for controlling the drive device is set to normal mode. If the power supply voltage drops, the control mode is set to a safe mode that controls at a lower voltage than the normal mode. The drive voltage output from the drive device to the light source is monitored according to the control mode. Determine whether the drive voltage is within the normal voltage range. If the drive voltage is in an abnormal voltage range outside the normal voltage range, it is determined that there is an abnormality in the light source. If the aforementioned abnormality occurs, a signal indicating the abnormality is output. Vehicle-mounted light-emitting device.

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