VEHICLE FRONT LIGHTING DEVICE

Abstract

Vehicle front lighting device (100, 150) for illuminating an area in front of a vehicle (1) using several lighting devices (LED 1 to LED 12) in a divided manner, wherein the vehicle front lighting device comprises: a lighting device array (10) in which the lighting devices are connected in series; several bypass circuits (21) arranged for the respective lighting devices and allowing a current flowing through the lighting devices to bypass the lighting devices; several switching elements (SW1 to SW12) arranged for the respective bypass circuits to open and close the bypass circuits; a lighting control unit (22) which controls a lighting mode of the lighting device array by bringing the switching elements corresponding to the lighting devices to be switched on into an open state and bringing the switching elements corresponding to the lighting devices to be switched off into a closed state; a current measurement unit (23) that measures the value of a current flowing through the lighting device array; a voltage control unit (24) that applies a voltage to the lighting array and controls the value of the applied voltage to ensure that the current flowing through the lighting array reaches a predetermined setpoint; and an interruption detection unit (25) that determines whether the number of switching elements that are in the open state matches the controlled voltage value and determines that there is an interruption in any of the bypass circuits if it does not match, wherein The lighting control unit switches the lighting devices on and off in a predetermined cycle by opening and closing the switching elements in the predetermined cycle with phases shifted relative to each other under the switching elements. When the lighting control unit receives information about a target brightness for illuminating the area in front of the vehicle for the respective lighting devices, it controls a time fraction of the open state in the predetermined cycle of each of the switching elements corresponding to the respective lighting devices, according to the target brightness, and The interruption detection unit determines whether there is an interruption in the bypass circuits by determining whether the number of switching elements in the open state, which varies in the predetermined cycle, matches the value of the voltage in the predetermined cycle, which is controlled by the voltage value control unit.

Description

[0001] This application is based on Japanese Patent Application No. 2017-242522 filed on December 19, 2017, the disclosure of which is hereby incorporated by reference. Technical area

[0002] The present invention relates to a vehicle front lighting device which uses several lighting devices to illuminate an area in front of a vehicle jointly or in a divided manner. State of the art

[0003] For a front lighting device mounted on a subject vehicle, it is desirable to be able to project high luminance or brightness over a long distance and a wide area, enabling the driver of the subject vehicle to perceive the situation at that distance. To prevent the high luminance from causing glare for the driver of an oncoming vehicle, it is desirable to be able to reduce the luminance or brightness of the light illuminating the area where the oncoming vehicle is located.

[0004] Therefore, a technique has been proposed in which a plurality of lighting devices are mounted to illuminate a front side of the vehicle, and the respective lighting devices are used to illuminate a region in front of the vehicle collectively or in a divided manner (Patent Literature 1).

[0005] If, using the above technique, there is no oncoming vehicle, pedestrian, or similar object present, the driver of the subject vehicle can easily perceive the distant situation by the high brightness of the light emitted over a wide area and at that distance. Conversely, if an oncoming vehicle, pedestrian, or similar object is detected, a situation in which the driver of the oncoming vehicle, pedestrian, or similar object experiences glare can be avoided by reducing the brightness of the lighting device responsible for the area where the oncoming vehicle, pedestrian, or similar object is located, or by switching off the lighting device.

[0006] Furthermore, the technique described above involves a gradual increase in the number of lights mounted on the vehicle. This is because, as the number of lights increases, the area illuminated by each individual light becomes smaller. This prevents situations where the light is dimmed in an area where an oncoming vehicle is not present, for example, when the oncoming vehicle is detected and the light's brightness is reduced or switched off. Alternatively, increasing the number of lights divides the area in front of the vehicle into smaller zones, thus allowing the distribution of light illuminating the front of the vehicle to be more evenly distributed. State of the art literaturePatent literature

[0007] PTL 1: JP 2008 - 37 240 A Summary

[0008] However, if the number of lighting devices fitted to the vehicle is increased, the number of wires or cables or wiring to control the lighting devices also increases, making it difficult to detect whether there is a break in a cable or wiring.

[0009] It is an object of the present invention to provide a vehicle front device that is able to detect the presence or absence of an interruption in a cable or wiring for controlling lighting devices, even when several lighting devices are mounted for joint or shared illumination of a front of a vehicle.

[0010] A vehicle front lighting device according to one aspect of the present invention serves to illuminate an area in front of a vehicle using several lighting devices in a divided manner and comprises a lighting device array in which the lighting devices are connected in series, several bypass circuits arranged for the respective lighting devices and allowing a current flowing through the lighting devices to bypass the lighting devices, several switching elements arranged for the respective bypass circuits to open and close the bypass circuits, a lighting control unit, a current sensing unit, a voltage control unit and an interruption detection unit.The lighting control unit controls a lighting mode of the lighting device array by bringing the switching elements corresponding to the lighting devices to be turned on into an open state and bringing the switching elements corresponding to the lighting devices to be turned off into a closed state. The current value detection unit detects a value of a current flowing through the lighting device array. The voltage value control unit applies a voltage to the lighting device array and controls a value of the voltage to be applied to cause the value of the current flowing through the lighting device array to reach a predetermined target current value.The interruption unit determines whether the number of switching elements that are in the open state matches the controlled value of the voltage and determines that an interruption occurs in any of the bypass circuits if it does not match.

[0011] In the vehicle front lighting device described above, the presence or absence of a break can be determined based on whether the number of lighting devices to be turned on matches the value of the applied voltage, and therefore, even in the case where the area in front of the vehicle is illuminated using the lighting devices, the presence or absence of the break in the wiring for driving the lighting devices can be easily detected. Short description of the drawings

[0012] The above and further problems, features and advantages of the present invention will become clear with reference to the following detailed description and the accompanying drawings. These show: Fig. 1A a diagram showing a vehicle on which a vehicle front lighting device according to an embodiment of the present invention is mounted; Fig. 1B an example diagram showing the vehicle front lighting device mounted on the vehicle; Fig. 2 a block diagram showing an internal structure of the vehicle's front lighting device; Fig. 3A an example diagram of the operation of the vehicle front lighting device for the simultaneous illumination of several LEDs of an LED array; Fig. 3B an example diagram of the operation of the vehicle's front lighting device for the individual illumination of the LEDs of the LED array; Fig. 4 An example diagram showing a method for changing the luminance or brightness of the LEDs by the vehicle's front lighting device; Fig. 5 is an example diagram illustrating a state in which the vehicle front lighting device illuminates an area in front of the vehicle by lighting the LEDs of the LED array at the same brightness; Fig. 6A a diagram showing the times of switching on and off of the LEDs, which are determined according to a light distribution pattern by the vehicle's front lighting device; Fig. 6B a diagram showing a state in which the number of lit LEDs or illuminated LEDs of the vehicle's front lighting device changes over time; Fig. 7A is an example diagram showing a condition where there is no break in the bypass wiring; Fig. 7B is an example diagram showing an exemplary effect of interrupting the bypass wiring on the operation of the LEDs of the LED array; Fig. 8A is an example diagram showing another exemplary effect of interrupting the bypass wiring on the operation of the LEDs of the LED array; Fig. Figure 8B shows an example diagram illustrating another exemplary effect of interrupting the bypass wiring on the operation of the LEDs of the LED array; Fig. 9A An example diagram of a principle for detecting the presence or absence of an interruption in a bypass wiring in the vehicle front lighting device; Fig. 9B an example diagram of a principle for detecting the presence or absence of an interruption in the bypass wiring in the vehicle front lighting device; Fig. 10 a flowchart showing the first half of a lighting control process performed by the vehicle's front lighting device; Fig. 11 a flowchart showing a second half of the lighting control process performed by the vehicle's front lighting device; Fig. 12A an example diagram of a detection time DT for detecting the presence or absence of an interruption during the lighting control process; Fig. Figure 12B shows an enlarged view showing a change in the number of illuminated LEDs between before and after a time T1 in Fig. 12A and indicates a change in the value of the applied voltage; Fig. 12C an enlarged view showing a change in the number of illuminated LEDs between before and after a time T11 in Fig. 12A and indicates a change in the value of the applied voltage; Fig. 13 an example diagram representing a lighting plan used to capture a break position in a lighting control process according to a first modification; and Fig. 14 a block diagram showing an internal structure of a vehicle front lighting device according to a second modification. Description of the embodiments

[0013] A vehicle front lighting device 100 according to an embodiment of the present invention is described with reference to the drawings. Fig. Figure 1A shows a vehicle 1 on which a vehicle front lighting device (FL) 100 is mounted. As shown in Fig. As shown in FIG. 1A, a front lighting device 100 is mounted on each of the left and right sides of the vehicle 1, and each vehicle front lighting device 100 includes an LED array 10 in which a plurality of light-emitting diodes (hereinafter referred to as LEDs) are arranged in a row, and a control module (CM) 20 for controlling the lighting operation of the individual LEDs constituting the LED array 10. The LED arrays 10 are mounted one-by-one under headlights 2 mounted on the front left and right sides of the vehicle 1, and the control modules 20 are mounted inside the vehicle 1 within the LED arrays 10.

[0014] As it is in Fig. 1B, the control modules 20 are connected to a lamp ECU (LE) 50 mounted on the vehicle, and control the operation of lighting the individual LEDs constituting each LED array 10 according to an instruction or command from the lamp ECU 50. The lamp ECU 50 is connected to an on-vehicle LAN 30 that controls the ECUs (not shown) mounted on the vehicle 1, and determines a command content to be output to the lamp ECU 50 based on information received from other control ECUs via the on-vehicle LAN 30.

[0015] Fig. 2 shows a rough internal structure of the vehicle front lighting device 100 according to the present embodiment. As shown in Fig. As shown in FIG. 2, the vehicle front lighting device 100 according to the present embodiment includes the LED arrays 10 and the control modules 20. The LED arrays 10 are each configured such that the LEDs 1 to LEDs 12 are connected in series, and a cathode side of the LEDs 12 is grounded to GND. In the present embodiment, the LEDs 1 to LEDs 12 correspond to the "lighting devices" of the present invention, and the LED array 10 corresponds to a "lighting device array" of the present invention.

[0016] The control modules 20 each include the same number of switching elements SW1 to SW12 as the number of LEDs 1 to LED 12 in the LED arrays 10, and the switching elements SW1 to SW12 are connected in series. A bypass wiring 21a, drawn from an anode side (i.e., a side not connected to the LED 2) of the LED 1, is connected to an upstream side (i.e., a side not connected to the switching element SW2) of the switching element SW1. A bypass wiring 21b, drawn from between the LED 1 and the LED 2, is connected between the switching element SW1 and the switching element SW2. Furthermore, a bypass wiring 21c, drawn from between the LED 2 and the LED 3, is connected between the switching element SW2 and the switching element SW3.In the same way, bypass wiring 21d to 21l, which extends from between LED 3 to LED 12, is connected between switching element SW3 and switching element SW12. A bypass wiring 21m, which extends from a cathode side (i.e., a side grounded to GND) of LED 12, is connected to a downstream side (i.e., a side not connected to switching element SW11) of switching element SW12.

[0017] When switching element SW1 is brought into a conducting state, bypass wiring 21a and bypass wiring 21b through switching element SW1 become conductive, and consequently, a bypass circuit 21 is formed that bypasses LED 1. When switching element SW2 is brought into a conducting state, bypass wiring 21b and bypass wiring 21c through switching element SW2 become conductive, and consequently, a bypass circuit 21 is formed that bypasses LED 2. When switching elements SW3 to SW12 are similarly brought into a conducting state, the respective bypass circuits 21 are formed to bypass LEDs 3 to LED 12. A power transistor, designated as a switching element, is used as each of the respective switching elements SW1 to SW12.The power transistor has three terminals, and when a control terminal among these terminals is brought into a high state, the other two terminals become conductive, and when the control terminal is brought into a low state, the other two terminals become non-conductive.

[0018] In addition to the switching elements SW1 to SW12, the control module 20 also contains a lighting control unit (LC) 22, a current value detection unit 23, a voltage value control unit (VC) 24 and an interruption detection unit (DD) 25.

[0019] Note that these "units" are abstract concepts according to which, for the sake of simplicity, the interior of the control module 20 is classified, focusing on the functions of the control module 20 of the vehicle's front lighting device 100, so that the control module 20 illuminates LEDs 1 to 12 and detects the presence or absence of an open circuit in the bypass wiring 21a to 21m. Therefore, it is not implied that the control module 20 of the vehicle's front lighting device 100 is physically divided into these "units." These "units" can be implemented as a computer program executed by a CPU, as an electronic circuit containing an LSI and memory, or by combining the computer program with the electronic circuit.

[0020] The lighting control unit 22 is connected to control terminals of the switching elements SW1 to SW12, and the control terminals of the respective switching elements SW1 to SW12 can be individually set to a high state or a low state.

[0021] The current sensing unit 23 is connected in series with the LED array 10 and can detect the current flowing through the LED array 10. Since LEDs 1 to 12 within the LED array 10 are connected in series, the current value detected by the current sensing unit 23 is the value of the current flowing through each of LEDs 1 to 12.

[0022] The voltage control unit 24 applies a voltage to the LED array 10, receives a value of a current flowing through the LED array 10 from the current sensing unit 23 and controls a value of the voltage to be applied to the LED array so that the current value becomes equal to a predetermined target current value.

[0023] The interruption detection unit 25 receives the number of switching elements SW1 to SW12 whose control terminals are in the low state from the lighting control unit 22 and receives the value of the voltage applied to the LED array 10 from the voltage value control unit 24. Then the presence or absence of an interruption of the bypass wiring 21a to 21m is detected by determining whether the number of switching elements SW1 to SW2 corresponds to the voltage value.

[0024] In the following, a method for detecting the presence or absence of an interruption in the bypass wiring 21a to 21m by the vehicle front lighting device 100 according to the present embodiment is described, and in preparation, the operation of illuminating the LEDs 1 to 12 by the vehicle front lighting device 100 is described.

[0025] The Fig. 3A and Fig. Figure 3B shows the operation of switching LEDs 1 to 12 on or off by the vehicle front lighting device 100 according to the present embodiment. In the LED array 10, 12 LEDs, i.e., LEDs 1 to 12, are connected in series (see Figure 3B). Fig. 2); however, in order not to complicate the illustration, LEDs 7 to 12 are in the Fig. 3A to 3B are omitted. Therefore, in the description of the Fig. 3A and Fig. 3B assume that the LED array 10 contains six LEDs connected in series, i.e. LED 1 to LED 6, and that the switching elements contain the six switching elements SW1 to SW6.

[0026] If the respective control terminals of the switching elements SW1 to SW6 are in a low state, all switching elements SW1 to SW6 are in an open state, as described in Fig. 3A is shown. When a voltage is applied from the voltage value control unit 24 to the LED array 10, a current therefore flows through the LEDs 1 to 6, as indicated by the thick solid line in the drawing, and the LEDs 1 to 6 are switched on.

[0027] As it is in Fig. As shown in Figure 3B, the control terminal of switching element SW2 is set to a high state (Hi). Switching element SW2 is then in the conducting state, and the bypass circuit 21, which bypasses LED 2 (i.e., bypass wiring 21b, switching element SW2, and bypass wiring 21c), is connected to the bypass circuit 21. Since the resistance of the LEDs is generally greater than the resistance of the bypass circuit 21, any current that would otherwise flow through LED 2 flows through switching element SW2 via the bypass circuit 21, thus switching off LED 2.

[0028] When the control terminals of switching element SW4 and switching element SW5 are high, switching element SW4 and switching element SW5 are in the conductive state. Accordingly, a current that would normally flow through LED 4 and LED 5 flows through the bypass circuit 21 (i.e., bypass wiring 21d, switching element SW4, switching element SW5, and bypass wiring 21f), through switching element SW4 and switching element SW5, and LED 4 and LED 5 are turned off.

[0029] In Fig. 3B represents a thick solid line, a path through which current flows when the control terminals of switching element SW2, switching element SW4, and switching element SW5 are in the high state. In the example of the Fig. Therefore, light is emitted from LED 1, LED 3 and LED 6 in 3B.

[0030] If, as it appears from the Fig. 3A and Fig. 3B, when the lighting control unit 22 sets a control terminal of a particular switching element to the low state, the LED corresponding to the switching element SW is turned on. Conversely, when the control terminal is set to the high state, the LED corresponding to the switching element SW is turned off. Regardless of which LED is turned on, a current value of the current flowing through a respective LED is a current value detected by the current value detection unit 23.

[0031] In the example that is in Fig. As shown, 3A means a current flows through six LEDs, but in the example that in Fig. As shown in Figure 3B, a current flows through three LEDs and three switching elements. Since, in this example, the resistance of the switching elements is sufficiently smaller than the resistance of the LEDs, the resistance of a path through which the current flows is reduced by switching from the state of Fig. 3A in the state of Fig. 3B halves. If the value of the voltage applied by the voltage control unit 24 is not changed, the value of the current flowing through each LED is doubled. Conversely, to maintain the value of the current flowing through each LED, it is necessary to halve the value of the voltage applied by the voltage control unit 24.

[0032] Therefore, the voltage control unit 24 detects the current value of the LED through the current sensing unit 23 and controls the value of the applied voltage in such a way that the current value becomes equal to a predetermined target current value.

[0033] Since the current to the LED is controlled or regulated to a constant target current value in this way, the luminance or brightness of the LED can also be changed by altering the current value. Therefore, the brightness of the LED is changed using the following method.

[0034] Fig. Figure 4 shows how to change the brightness of the LED. As shown in Fig. As shown in Figure 4, the LED is repeatedly turned on and off in a predetermined lighting cycle. In this example, if the lighting cycle is set to a short period of time that is not perceptible to a human, by reducing the proportion of lighting time within the lighting cycle, the human may feel that the brightness of the LED is decreasing. Conversely, if the proportion of lighting time is increased, the human may feel that the brightness of the LED is increasing.

[0035] In the vehicle front lighting device 100 according to the present embodiment, the brightness of the LED is therefore changed by altering the time at which the LED is switched off after it has been periodically switched on in a predetermined lighting cycle. A state in which the lighting time in the lighting cycle is equal to "0" means switched off, and the lighting state is a state of maximum brightness during the lighting cycle. In the vehicle front lighting device 100 according to the present embodiment, the lighting cycle is approximately 3 ms.

[0036] As mentioned above with reference to Fig. As described in Figure 2, 12 LEDs, i.e., LED 1 to LED 12, are arranged in the LED array 10. The brightness of any one of the LEDs 1 to 12 is adjusted by changing the switch-off time after the LED has been periodically switched on in a predetermined lighting cycle. However, the lighting cycles of LEDs 1 to 12 are set to be out of phase, thus resulting in different switch-on times for each LED.

[0037] Fig. Figure 5 shows a state in which LEDs 1 to 12 are switched on at different times. In the example shown in Fig. As shown in Figure 5, the duty cycle for each of LEDs 1 to 12 is 50%. Here, the duty cycle represents a ratio or proportion of the time the LED is switched on to the lighting cycle.

[0038] As shown in the figure, LED 1 is switched on at time T1, LED 2 is switched on at time T2, and LED 3 is switched on at time T3. Similarly, LEDs 4 through 12 are switched on sequentially at times T4 through T12. LEDs 1 through 12, switched on in this order, are switched off after a predetermined time has elapsed since they first illuminated (in this example, half the illumination cycle, as the illumination duty cycle is set to 50%). After the illumination cycle has elapsed following the illumination of LED 1, LED 1 is switched on again, and then LEDs 2 through 12 are switched on sequentially.

[0039] When LEDs 1 to 12 are switched on simultaneously, the resistance value of a path through which the voltage control unit 24 causes a current flow becomes the resistance value of 12 LEDs, and therefore the voltage control unit 24 must apply a large voltage (see Fig. 3A). When LEDs 1 to 12 are switched on simultaneously, they will switch off simultaneously after a time interval corresponding to the duty cycle. Since the resistance of the current path rapidly decreases to the resistance of the 12 switching elements, it is necessary to rapidly reduce the voltage applied by the voltage control unit 24. Therefore, when LEDs 1 to 12 are switched on simultaneously, high voltages must be applied. As described above, when LEDs 1 to 12 are switched on simultaneously, the voltage control unit 24 must vary the applied voltage significantly.

[0040] On the other hand, as in Fig. As shown in Figure 5, LEDs 1 to 12 are switched on sequentially and then switched off sequentially when the phases of the illumination cycle of LEDs 1 to 12 are shifted relative to each other, so that the change in the value of the voltage applied by the voltage control unit 24 can be reduced. In particular, in the example shown in Fig. As shown in Figure 5, the duty cycle of LEDs 1 to 12 is 50%, and therefore the number of LEDs illuminated simultaneously is six. For this reason, the voltage control unit 24 does not need to change the voltage value.

[0041] The brightness at which LEDs 1 to 12 are illuminated changes according to information such as the ambient conditions of vehicle 1, the presence or absence of an oncoming vehicle, pedestrian, or similar object, and information such as the position at which the oncoming vehicle or pedestrian is detected. As mentioned above with reference to Fig. As described in 1B, the lighting ECU 50, when mounted on the vehicle 1, obtains this information via the vehicle's LAN 30, determines the distribution of brightness with which LEDs 1 to LEDs 12 are switched on (so-called light distribution pattern) and outputs the distribution to the vehicle's front lighting device 100. The control module 20 of the vehicle's front lighting device 100 then determines the times at which LEDs 1 to LEDs 12 are switched on and off, according to the light distribution pattern.

[0042] In Fig. Figure 6A shows the times at which LEDs 1 to 12 are switched on and off according to the light distribution pattern. In the example shown in Fig. As shown in Figure 6A, the duty cycle of LED 1 and LED 2 in the light distribution pattern is 30%, the duty cycle of LED 3 is 50%, the duty cycle of LED 4 is 60%, the duty cycle of LED 5 and LED 6 is 80%, the duty cycle of LED 9 and LED 10 is 60%, and the duty cycle of LED 11 and LED 12 is 50%.

[0043] As mentioned above with reference to Fig. As described in section 5, LEDs 1 to 12 are switched on sequentially at times T1 to T12. Since the duty cycle of LED 1 is 30%, LED 1 is switched off at a time when 30% of its illumination cycle has elapsed after it was switched on at time T1. Since LED 2 has a duty cycle of 30%, LED 2 is switched off at a time when 30% of its illumination cycle has elapsed after it was switched on at time T2. Since LED 3 has a duty cycle of 50%, LED 3 is switched off at a time when 50% of its illumination cycle has elapsed after it was switched on at time T3.Subsequently, LEDs 4 to 12 are switched off in the same manner at a time corresponding to a specific duty cycle after each LED has been switched on in sequence at the respective time T4 to T12. In this way, the times at which LEDs 1 to 12 are switched on and off can be determined according to the light distribution pattern.

[0044] In this description, the timings at which LEDs 1 to LED 12 are turned on and off, which are determined according to the light distribution pattern, are referred to as a "lighting schedule." Since the timings at which LEDs 1 to LED 12 are turned on are determined in advance according to the present embodiment, only the turn-off timings are actually determined. However, the timings at which LEDs 1 to LED 12 are turned on can also be changed as needed.

[0045] After the lighting plan of LED 1 to LED 12 has been determined as described above, LED 1 to LED 12 are switched on or off by moving the control connections of the switching elements SW1 to SW12 to a low or high state according to the lighting plan.

[0046] When the lighting plan of LED 1 to LED 12 is determined, the number of LEDs to be turned on (hereinafter referred to as the number of illuminated LEDs) changes over time. Fig. Figure 6B shows a state in which the number of LEDs illuminates changes at respective moments over time.

[0047] As mentioned above with reference to the Fig. 3A and Fig. As described in 3B, the resistance value of the path through which current flows is proportional to the number of illuminated LEDs. If the voltage value of the voltage control unit 24 is controlled such that the current value detected by the current sensing unit 23 reaches a predetermined target current value, while LEDs 1 to 12 illuminate according to the lighting plan described in Fig. 6A are turned on or off, the voltage value becomes a voltage value that changes proportionally to the number of LEDs illuminated.

[0048] Upon receiving the light distribution pattern from the lighting ECU 50, the vehicle front lighting device 100, according to the present embodiment, sets the control terminals of the switching elements SW1 to SW12 to the low or high state according to the lighting plan determined as described above. With the above operation, the front of the vehicle 1 can be illuminated with the light distribution pattern determined by the lighting ECU 50.

[0049] LEDs 1 to LED 12 of LED array 10 and switching elements SW1 to SW12 of control module 20 are connected to each other via bypass wiring 21a to 21m. If an open circuit occurs in any of the bypass wiring 21a to 21m, the front side cannot be illuminated with the light distribution pattern determined by lamp ECU 50, and therefore, there is a need to be able to quickly detect the open circuit when such an open circuit occurs.

[0050] As described above, there is a tendency for the number of LEDs mounted in the LED array 10 to increase year after year, and as the number of LEDs increases, so does the number of bypass wires, making it more difficult to detect a break each year. Therefore, the vehicle front lighting device 100, according to the present embodiment, uses the following method to be able to quickly and easily detect a break in the bypass wiring even when the number of LEDs mounted in the LED array 10 is greater.

[0051] The Fig. 7A and Fig. Figure 7B shows an example of a state in which a current-carrying path changes due to the occurrence of an interruption in the bypass wiring. As described above, 12 LEDs, i.e., LEDs 1 to 12, are connected in the LED array 10 of the present embodiment, but to avoid complicating the illustration, LEDs 7 to 12 are shown in the Fig. 7A and Fig. 7B as in the Fig. 3A and Fig. 3B is not shown. Accordingly, the description of the Fig. 7A and Fig. 7B assume that six LEDs, i.e. LED 1 to LED 6, are connected in series in the LED array 10, and six switches, i.e. switching element SW1 to switching element SW6, are present.

[0052] Fig. Figure 7A shows a situation where no interruption occurs. As shown in Fig. As shown in Figure 7A, a current flows through a path indicated by a thick solid line in the drawing when the control terminals of switching elements SW1, SW3, and SW6 are in a low state and the control terminals of switching elements SW2, SW4, and SW5 are in a high state. Consequently, LEDs 1, 3, and 6 are on, and LEDs 2, 4, and 5 are off.

[0053] In this situation, it is now assumed that an interruption occurs in the bypass wiring 21d. Since, as in Fig. Figure 7A shows that the bypass wiring 21d is a path that bypasses the current flow through LED 4. Therefore, if the bypass wiring 21d is broken, the current cannot bypass LED 4. Even if the control terminal of switching element SW4 is in the high state and switching element SW4 is in the conducting state, current will still flow through LED 4, and LED 4 will be switched on.

[0054] A thick solid line in Fig. 7B represents a path through which current is flowing at this time. Additionally, a marker X in the drawing indicates that there is an open circuit in the bypass wiring 21d. Furthermore, the dashed circle around LED 4 in the drawing indicates that LED 4 is actually on, even though it should be off in response to the switching element SW4 being conductive.

[0055] According to Fig. 7B describes a case where the broken bypass wiring 21d is part of the path for bypassing the LED 4. When the bypass wiring 21d, which is a bypass of the current through the LED 4, is broken, the current cannot bypass the LED 4 and flows through the LED 4, thereby turning on the LED 4.

[0056] The same applies if the broken bypass wiring 21d is part of the path to bypass LED 3.

[0057] Fig. Figure 8A shows a case where the switching element SW3 on a current-up side of the broken bypass wiring 21d is in a conducting state (i.e., the control terminal is high), and the switching element SW4 on a current-down side is in a broken state (i.e., the control terminal is low). Because the switching element SW3 is in the conducting state, the current initially bypasses LED 3, but the current cannot bypass LED 3 because the bypass wiring 21d, which is part of the bypass path, is broken. Consequently, a current flows through a path defined by a thick solid line in Figure 8A. Fig. 8A is specified, and LED 3 is switched on. Fig. 8A indicates that LED 3, surrounded by a dashed line, is actually switched on, even though LED 3 should naturally be switched off in response to the fact that the switching element SW3 is conducting.

[0058] Fig. Figure 8B, on the other hand, shows a situation in which both the switching element SW3 on the current-up side and the switching element SW4 on the current-down side of the interrupted bypass wiring 21b become conductive. Since switching elements SW3 and SW4 are conductive, the current bypasses LED 3 and LED 4. Because the bypass wiring 21d, which runs between LED 3 and LED 4, does not form part of a path through which the current bypasses LED 3 and LED 4, LED 3 and LED 4 remain off even if an interruption occurs in the bypass wiring 21d.

[0059] In contrast to the case that in Fig. As shown in Figure 8B, the current does not bypass LED 3 and LED 4 at the first position if both switching element SW3 on the current-up side and switching element SW4 on the current-down side of the interrupted bypass wiring 21d are interrupted. Since the bypass wiring 21d does not form part of the current's bypass path, LED 3 and LED 4 remain lit even if an interruption occurs in the bypass wiring 21d.

[0060] As can be seen from the description above, if a break occurs in a particular bypass wiring circuit, both LEDs will turn on even if one is switched on by the LED on the power-up side and the other on the power-down side of the bypass wiring, while the other is switched off. If both LEDs are to be switched on or off, both LEDs can be switched on or off as intended.

[0061] Even when attempting to switch LEDs 1 to 12 on and off according to a predetermined lighting schedule, the number of LEDs actually switched on (hereinafter referred to as the number of actual lit LEDs) is greater than the number of lit LEDs determined according to the lighting schedule if there is an interrupted bypass wiring.

[0062] Fig. 9A represents an example where LEDs 1 to 12 are connected according to the lighting plan shown in Fig. 6A shows that the LEDs can be switched on and off while the bypass wiring 21d, which runs from between LED 3 and LED 4, is interrupted. The diagonally dashed sections in Fig. 9A indicate that the LEDs are inadvertently turned on because the bypass wiring 21d is interrupted. For example, LED 4 is turned on together with LED 3 because LED 3 turns on when LED 4 is turned on, even though the time has not yet come. Furthermore, LED 3 remains on because LED 4 continues to turn on even though the time for LED 3 to turn off has come.

[0063] Therefore, the number of actual luminaires with which the LEDs are actually switched on is greater than the number of LEDs that the lighting plan attempts to switch on. The shaded sections in Fig. 9B indicate the number of LEDs that increases due to an interruption. As stated above with reference to the Fig. 3A and Fig. As described in 3B, since the voltage value control unit 24 controls the value of the voltage to be applied to the LED array 10 such that the value of the current flowing through the LEDs becomes equal to the set current value, the voltage value to be applied by the voltage value control unit 24 is proportional to the number of LEDs that are actually switched on (i.e. the number of actual lit LEDs).

[0064] Therefore, if the voltage value applied to the LED array 10 by the voltage value control unit 24 increases or decreases according to a change in the number of LEDs as determined by the lighting plan, no interruption occurs, but if the change in the number of LEDs and the increase or decrease in the voltage value do not match each other (for example, if the increase or decrease in the voltage value is greater or less than the change in the number of LEDs), it can be determined that an interruption has occurred.

[0065] Based on the principle described above, the vehicle front lighting device 100 according to the present embodiment detects the presence or absence of a break in the bypass wirings 21a to 21m connecting the LED array 10 and the control module 20.

[0066] The Fig. 10 and Fig. Figure 11 shows flowcharts of a lighting control process carried out by the vehicle front lighting device 100 according to the present embodiment to illuminate an area in front of the vehicle 1 using the LED array 10.

[0067] As shown in the figure, when the lighting control process is started, it is first determined whether lighting is to be started using the LED array 10 (S100). In the present embodiment, the lamp ECU 50 determines whether lighting is required based on the information acquired from the on-vehicle LAN 30 and outputs the result to the vehicle front lighting device 100. Therefore, if an instruction to start lighting is not received from the lamp ECU 50, it is determined that lighting is not to be started (No in S100), and the lighting control process is in a wait state while repeating the same determination until the command to start lighting is received.

[0068] When a lighting start command is received, the lighting start is determined (Yes in S100), and the light distribution pattern is acquired from the lighting ECU 50 (S101). As described above, the light distribution pattern is information indicating the brightness at which the LEDs of the LED array 10 are turned on.

[0069] Subsequently, a lighting plan is generated according to the light distribution pattern (S102). As described above, the lighting plan consists of data indicating a schedule of times at which the LEDs forming the LED array 10 are turned on and off. As exemplified in Fig. 6A, the Fig. The lighting plan shown in 6A is generated when the light distribution pattern is a pattern according to which the duty cycle of LED 1 and LED 2 is 30%, the duty cycle of LED 3 is 50%, the duty cycle of LED 4 is 60%, the duty cycle of LEDs 5 to 8 is 80%, the duty cycle of LEDs 9 and 10 is 60%, and the duty cycle of LEDs 11 and 12 is 50%.

[0070] Then, according to the generated lighting plan, the switching elements SWs corresponding to the respective LEDs are activated (S103). In other words, according to the lighting plan, the operation to move the control terminal of the switching element SW of the LED to be switched on to the low state and to move the control terminal of the switching element SW of the LED to be switched off to the high state is repeated in the lighting cycle of the LED.

[0071] Next, it is determined whether a command is issued by the lighting ECU 50 (S104), and if no command to stop the lighting is issued by the lighting ECU 50, it is determined that the lighting will not stop (No in S104), and then it is determined whether the lighting cycle has elapsed (S105).

[0072] If the lighting cycle has not yet elapsed since the control of the switching element SW was started, "No" is determined in S105, and it is determined whether the current time is an interrupt detection time DT (S110 in Fig. 11) The detection time DT is set to a time at which a predetermined interval period IT has elapsed since a respective LED of the LED array 10 was switched on. In other words, if, as above with reference to the Fig. 6A and Fig. As described in Figure 6B, the LED array 10 includes LEDs 1 to 12, LEDs 1 to 12 are sequentially turned on at respective times T1 to T12. Twelve times at which the predetermined interval period IT has elapsed since the respective times T1 to T12 become the interruption detection time DT.

[0073] The reason why the interrupt detection time DT is set to such a time is as follows.

[0074] Fig. 12A represents a state in which the number of illuminated LEDs changes over time as LEDs 1 to 12 of the LED array 10 are switched on according to the lighting plan. As described above, a voltage applied to the LED array 10 by the voltage control unit 24 increases or decreases proportionally to the number of LEDs being switched on.

[0075] Since in this example the voltage value control unit 24 controls the voltage value in such a way that the current value detected by the current value sensing unit 23 reaches the target current value, a time delay occurs in the change of the voltage value when the number of light-up LEDs is changed.

[0076] Fig. 12B shows an enlarged view of a change in the number of LEDs lit and a change in the applied voltage value before and after time T1. As shown in the figure, since the voltage value indicated by a dashed line in the figure continuously changes differently from the number of LEDs lit, which is indicated by a solid line, a certain amount of time is required before the voltage value stabilizes. Therefore, a time required for the voltage value to stabilize with a margin (i.e., an interval period IT) is determined in advance, and a time at which the interval period IT has elapsed since times T1 to T12 at which LED 1 to LED 12 were respectively lit is set as a break detection time DT.The above setting prevents the erroneous detection of an interruption due to the detection of a voltage value before stabilization.

[0077] If the interval period IT has not elapsed since the respective times T1 to T12 at which the respective LED 1 to LED 12 were turned on, it is determined that the time is not an open circuit detection time (No in S 110 of the Fig. 11), and then the river returns to S104 in Fig. 10, at which it is determined whether the lighting should be stopped. If the lighting should not be stopped (No in S104), it is determined whether the lighting cycle has elapsed (S105), and if the lighting cycle has not elapsed (No in S105), it is determined again whether the time is an interruption detection time (S110 in Fig. 11).

[0078] Even during the above operation is repeated, the control of the switching elements SWs, which are described in S103 in Fig. Once started at 10, the lighting plan will continue.

[0079] If the current time is an interruption recording time DT (Yes in S110 in Fig. 11), it is then determined whether there is any LED to be switched off within a predetermined period (S111). In this example, the predetermined period is set to a time obtained by adding a predetermined grace period dT (a time shorter than the interval period IT) to the interval period IT.

[0080] If there is no LED to be switched off within the predetermined period (No in S111), the following operation is started to detect whether there is an interruption; however, if there is an LED to be switched off within the predetermined period (Yes in S111), it is determined whether the illumination should be stopped without detecting an interruption (S104 in Fig. 10). The reason for this is as follows.

[0081] Fig. Figure 12C shows an enlarged view of a change in the number of illuminated LEDs and a change in the applied voltage before and after time T11. As mentioned above with reference to the Fig. 6A and Fig. As described in 6B, the number of LEDs is incremented by one, thereby increasing the value of the applied voltage, as indicated by the dashed line in Fig. The value T11 is specified as 12C because it is the time when LED 11 is switched on. However, before the voltage stabilizes (i.e., before the detection time DT occurs), the other LEDs are switched off, and the number of lit LEDs is decremented by one. As a result, the increased voltage value decreases.

[0082] If there is an LED to be switched off during the period from the lighting time (T11 in this example) until the interval period IT has elapsed, the voltage value will therefore be recorded during the decrease if the voltage value is recorded at the interruption detection time DT, so that no correct voltage value can be recorded.

[0083] It is also assumed that there is an LED that is being switched off at the acquisition time DT. Considering that it takes some time to acquire the voltage value, in this case the voltage value begins to decrease while the voltage value is being acquired, and the correct voltage value cannot be acquired. If there is an LED that is to be switched off during a period from the acquisition time DT until the elapse of a grace period dT, where the time required to acquire the voltage value is the grace period dT, there is a possibility that the correct voltage value cannot be acquired.

[0084] Therefore, in S111 the Fig. 11 determines whether there is any LED to be turned off within a predetermined period from any of the lighting times T1 to T12 until the interval period IT and the margin time dT have elapsed. If there is an LED to be turned off (Yes in S111), it is determined that there is a possibility that a correct voltage value cannot be detected, and then the flow returns to S104 in Fig. 10 back, without detecting whether there is an interruption, and it is determined whether the light should be turned off.

[0085] Since LEDs 1 to 12 are switched on and off according to a lighting plan that corresponds to the light distribution pattern (see Fig. 6A and Fig. 6B) is generated, it can also be easily determined with reference to the lighting plan whether there is an LED that is to be switched off within a predetermined period.

[0086] Since the grace period dT described above is indeed sufficiently shorter than the interval period IT, the grace period dT can simply be ignored. In this example, in S111 the Fig. 11 determines whether there is an LED to be switched off during a period from any of the illumination times T1 to T12 until the interval period IT has elapsed (i.e., until the interruption detection time DT has come).

[0087] If there is no LED to be switched off within the predetermined period (No in S111), the number of LEDs to be switched on (i.e., the number of LEDs to be turned on) is obtained (S112). The number of lit LEDs can be obtained based on the lighting schedule.

[0088] If no interruption occurs, the number of lit LEDs obtained in this way matches the number of LEDs that are actually switched on (i.e., the number of actual lit LEDs), but if an interruption occurs, the number of actual lit LEDs will be greater than the number of lit LEDs obtained based on the lighting plan (see Fig. 9A and Fig. 9B). Since the value of the voltage applied to the LED array 10 by the voltage value control unit 24 is determined according to the number of actual lit LEDs, it is possible to determine whether there is an interruption by determining whether the value of the voltage applied to the LED array 10 matches the number of lit LEDs obtained by the lighting plan.

[0089] In the present embodiment, however, before determining whether there is an interruption, it is determined whether the number of LEDs lit according to the lighting plan is less than a predetermined allowable number (S113). If the number of LEDs lit is greater than the allowable number (No in S113), it is again determined whether the lighting should be stopped without determining whether there is an interruption (S104 in Fig. 10). The reason for this is as follows.

[0090] As mentioned above with reference to the Fig. 9A and Fig. As described in Section 9B, in the vehicle front lighting device 100 according to the present embodiment, LEDs are switched on that should not be switched on if an interruption occurs in any of the bypass wiring 21a to 21m, so that the number of actual illuminated LEDs is greater than the number of illuminated LEDs based on the lighting plan. As a result, the resistance value of the LED array 10 increases, and the value of the voltage applied by the voltage control unit 24 also increases.

[0091] In this example, the resistance values ​​of the individual LEDs vary. Therefore, if the number N of illuminated LEDs is the number of LEDs with a larger resistance value, the resistance value becomes equivalent to the number (N+1) of LEDs, and it may be erroneously determined that an open circuit occurs. Conversely, since the number (N+1) of LEDs illuminated due to an open circuit is the number of LEDs with a smaller resistance value, a resistance value corresponding to the number N of LEDs is obtained, and it may be erroneously determined that no open circuit occurs. The possibility of such an erroneous determination increases as the number of illuminated LEDs increases.

[0092] Therefore, in the present embodiment, an appropriate allowable number is determined in advance according to a variation in the resistance value of the LEDs. If the number of LEDs determined according to the lighting plan is greater than the allowable number (No in S113), it is not determined whether there is an open circuit to avoid erroneous detection. The allowable number is set to 9 according to the present embodiment.

[0093] If, on the other hand, the number of light-emitting LEDs obtained on the basis of the lighting plan is equal to or less than the allowed number (Yes in S113), the value of the voltage applied to the LED array 10 is obtained (S114).

[0094] Then it is determined whether the number of LEDs obtained based on the lighting plan corresponds to the achieved voltage value (S115). In other words, if the number of LEDs is equal to N, the average resistance of the LEDs is equal to R, a variation or change in the resistance value is equal to dR, and a target current flowing through the LEDs is equal to I, then a current value V applied to the LED array 10 should satisfy the following expression. N⋅(R−dR)⋅l <V<N⋅(R+dR)⋅l

[0095] If the voltage value obtained in S114 is within a range that satisfies expression (1), it is determined that the number of LEDs and the voltage value are compatible (Yes in S115), and if the voltage value is not within the range that satisfies expression (1), it is determined that the number of LEDs and the voltage value are not compatible (No in S115).

[0096] As mentioned above with reference to the Fig. 9A and Fig. As described in 9B, in the vehicle front lighting device 100 according to the present embodiment, the number of LEDs to be switched on increases and does not decrease if an interruption occurs in the bypass wiring 21a to 21m. Therefore, in S115, expression (1) is replaced by the following expression: V <N⋅(R+dR)⋅l

[0097] Then it can be determined whether the number of LEDs and the voltage value are compatible. This makes it possible to perform a determination even faster than in the case of expression (1).

[0098] If it is determined that the number of LEDs and the voltage value do not match (No in S115), the detection result "Open circuit" is therefore output to the outside (for example to the lighting ECU 50 in Fig. 1B) (S116), and then the river returns to S104 in Fig. Turn back 10, and it will be determined whether the glow should be stopped.

[0099] If, on the other hand, it is determined that the number of LEDs and the voltage value are compatible (yes in S115), the flow returns to S104 in Fig. Return to 10 without outputting the detection result, and it is determined whether the lighting should be stopped.

[0100] As described above, in the lighting control process according to the present embodiment, the operations described above (S115 and S116 in) are repeated. Fig. 11) detects whether there is an interruption when the control of the switching elements SWs is started according to the lighting plan which corresponds to the light distribution pattern (S103).

[0101] When the lighting cycle has elapsed, while the above operation is repeated (Yes in S105 of the Fig. 10), the light distribution pattern is obtained or procured by the luminaire ECU 50 (S106).

[0102] Then it is determined whether the newly obtained light distribution pattern has changed compared to the previously obtained light distribution pattern (S107). If there is no change in the light distribution pattern (No in S107), the sequence of processes described above (S110 to S116 in Fig. 11) repeated until the luminescence cycle has elapsed and the result of the determination in S105 is “Yes”.

[0103] If, on the other hand, the newly acquired light distribution pattern has changed compared to the previously acquired light distribution pattern (yes in S107), a new lighting plan is generated according to the new light distribution pattern (S108). After the control of the switching elements SW (S109) has started according to the new lighting plan, the processes from S110 to S116 are carried out. Fig. 11 is repeated until the lighting is to be stopped (Yes in S104) or the lighting cycle has elapsed (Yes in S105).

[0104] If it is finally determined that the lighting is to be stopped (Yes in S104 of the Fig. 10), the lighting control process of the Fig. 10 and Fig. 11 completed.

[0105] As described above, the vehicle front lighting device 100 according to the present embodiment can quickly detect the occurrence of an open circuit by means of the above-described lighting control process when an open circuit occurs in the bypass wirings 21a to 21m for controlling the lighting operation of the respective LEDs of the LED array 10.

[0106] Furthermore, when detecting an interruption, it is only necessary to determine whether the number of LEDs to be lit in the LED array 10 matches the voltage value applied to the LED array 10, so that it can be easily and quickly detected whether there is an interruption.

[0107] It goes without saying that if there is an LED to be switched off within the predetermined period (yes, in S111 of the Fig. 11), it cannot be detected whether there is an interruption when the number of LEDs to be switched on exceeds the allowed number (No in S113), but the LEDs to be switched on change over time (see Fig. 6B) and also vary depending on the light distribution pattern. Therefore, after a certain period of time has elapsed, it is possible to detect whether there is an interruption.

[0108] There are several modifications to the above embodiment. These modifications are briefly described below, focusing on the differences from the embodiment described above. First modification

[0109] In the above embodiment, the occurrence of a break is detected, but a section where the break occurs is not detected. In S115 of the Fig. However, it is possible to determine which of the LEDs should light up if it is determined that the number of lit LEDs and the voltage value do not match (No in S115) in order to detect the section where the interruption occurred.

[0110] In the example that is in the Fig. 9A and Fig. 9B, for example, a mismatch is detected at four sections, ie, the time DT after the time T3, the detection time DT after the time T9, the detection time DT after the time T10, and the detection time DT after the time T11.

[0111] In this example, at a first point (i.e., the detection time DT after time T3), LEDs 1 to LED 3 and LEDs 6 to LED 12 are to be switched on. As mentioned above with reference to the Fig. As described in sections 7A to 8B, the LEDs that are not to be switched on will be switched on if one of them is switched on from either the power-up side or the power-down side of the interrupted bypass wiring and the other side of the interrupted bypass wiring is switched off. Therefore, there is a possibility of an interruption at two sections, i.e., the bypass wiring 21d, which is pulled from the power-down side of LED 3 (see Fig. 2), and the bypass wiring 21f, which is pulled from the power side of LED 6 (see Fig. 2).

[0112] Furthermore, at a second point (i.e., the detection time DT after time T9), LEDs 4 to LED 9 are to be switched on, and therefore there is the possibility of an interruption at two sections, i.e., the bypass wiring 21d, which is pulled from the power side of LED 4, or the bypass wiring 21j (see Fig. 2), which is drawn from the power side of LED 9.

[0113] Therefore, based on the information from the LEDs that are to be switched on at these two sections (i.e., the detection time DT after times T3 and T9), it can be determined that the break location is at bypass wiring 21d. Even if a break occurs in multiple sections, a location where the break occurs can be determined by using the procedure described above for multiple sections for which there is a mismatch in the determination of S115 in Fig. 11 is determined.

[0114] Alternatively, in the lighting control process according to the present embodiment described above, the LED 1 to LED 12 may be turned on according to the lighting plan after it is determined that the lighting is to be started (Yes in S100 of the Fig. 10), to establish the interruption position as in Fig. 13 shown to be captured before the light distribution pattern is obtained from the lighting ECU 50 (S101).

[0115] In the lighting plan for recording the interruption position, which is in Fig. As shown in Figure 13, LEDs 1 to 12 are switched on sequentially. Therefore, if the number of lit LEDs and the voltage applied to the LED array 10 do not match, it can be immediately detected that the bypass wiring, which runs from the power side of the LED to be switched on, is broken. Even if the wiring is broken in several sections, these broken sections can be detected immediately. Second modification

[0116] In the above embodiment, it is not detected whether there is an interruption when the number of LEDs to be switched on (i.e., the number of illuminated LEDs) exceeds the predetermined allowed number.

[0117] However, the LEDs constituting the LED array 10 (LED 1 to LED 12 in the embodiment described above) may be divided into several groups so that the number of LEDs in each group does not exceed the allowable number.

[0118] Fig. Fig. 14 shows an internal structure of a vehicle front lighting device 150 according to a second modification, in which the LEDs of the LED array 10 are divided into a plurality of groups. The vehicle front lighting device 150 according to the second modification shown in Fig. 14 is different from the vehicle front lighting device 100 according to the present embodiment shown in Fig.Figure 2 shows that a voltage sensing unit (VD) 26a for sensing a value of a voltage applied to a group 10a from LED 1 to LED 6 and a voltage sensing unit (VD) 26b for sensing a value of a voltage applied to a group 10b from LED 7 to LED 12 are arranged.

[0119] In the vehicle front lighting device 150 according to the second modification, similar to the vehicle front lighting device 100 according to the present embodiment described above, the LEDs 1 to LEDs 12 are turned on or off by causing the lighting control unit 22 to set the control terminals of the switching elements SW1 to SW12 to a low state or a high state. The voltage value control unit 24 controls the voltage value to be applied to the LED array 10 so that the current value detected by the current value detection unit 23 reaches a predetermined target current value.

[0120] In the vehicle front lighting device 150 according to the second modification, the voltage detection unit 26a detects a value of a voltage applied to the LEDs 1 to LEDs 6 in the group 10a and outputs the detected voltage value to the open-circuit determination unit 25. The voltage detection unit 26b detects a value of a voltage applied to the LEDs 7 to LEDs 12 in the group 10b and outputs the detected voltage value to the open-circuit determination unit 25.

[0121] Then, the disconnection determination unit 25 determines for each of the groups 10a and 10b whether the number of LEDs to be turned on matches the applied voltage value, and if the number of LEDs to be turned on and the voltage value do not match, it is determined that a disconnection has occurred in the bypass wiring of the groups 10a and 10b.

[0122] In the above configuration, since the number of LEDs in the groups 10a and 10b can be set to be equal to or less than the allowable number, even if the number of LEDs in the LED array 10 increases, it is possible to detect whether there is an open circuit.

[0123] While the present invention has been described with reference to its embodiments, it should be understood that the invention is not limited to the embodiments and constructions. The present invention covers various modifications and equivalent arrangements. In addition to the various combinations and configurations, other combinations and configurations including more, fewer, or only a single element are possible within the scope of the present invention.

Claims

[1] Vehicle front lighting device (100, 150) for illuminating an area in front of a vehicle (1) using a plurality of lighting devices (LED 1 to LED 12) in a divided manner, the vehicle front lighting device comprising: a lighting device array (10) in which the lighting devices are connected in series; a plurality of bypass circuits (21) arranged for the respective lighting devices and allowing a current flowing through the lighting devices to bypass the lighting devices; a plurality of switching elements (SW1 to SW12) arranged for the respective bypass circuits to open and close the bypass circuits; a lighting control unit (22) that controls a lighting mode of the lighting device array by bringing the switching elements corresponding to the lighting devices to be turned on into an open state and bringing the switching elements corresponding to the lighting devices to be turned off into a closed state; a current value detecting unit (23) that detects a value of a current flowing through the lighting device array; a voltage value control unit (24) that applies a voltage to the lighting device array and controls a value of the voltage to be applied to cause the value of the current flowing through the lighting device array to reach a predetermined target current value; and a break determination unit (25) which determines whether the number of switching elements brought into the open state matches the controlled voltage value, and determines that there is a break in any of the bypass circuits if it does not match, wherein the lighting control unit switches the lighting devices on and off in a predetermined cycle by opening and closing the switching elements in the predetermined cycle with phases shifted between the switching elements, when the lighting control unit receives information about a target brightness for illuminating the area in front of the vehicle for the respective lighting devices, it controls a time proportion of the open state in the predetermined cycle of each of the switching elements corresponding to the respective lighting devices in accordance with the target brightness, and the open-circuit determining unit determines whether there is the open-circuit in the bypass circuits by determining whether the number of switching elements in the open state, which varies in the predetermined cycle, matches the value of the voltage in the predetermined cycle controlled by the voltage value controlling unit. [2] The vehicle front light device according to claim 1, wherein the disconnection determining unit makes the determination as to whether there is the disconnection at a predetermined timing set in synchronization with the predetermined cycle, and stops the determination when there is a switching element to be switched to the closed state within a predetermined period among the switching elements. [3] The vehicle front light device according to claim 1 or 2, wherein the disconnection determining unit determines whether there is the disconnection when the number of the switching elements to be in the closed state is equal to or less than a predetermined allowable number. [4] A vehicle front lighting device (150) according to claim 1 or 2, further comprising: a voltage detection unit (26a, 26b) which divides the lighting device array into a plurality of groups (10a, 10b) in which the lighting devices are connected in series, and detects a value of a voltage to be applied to the respective groups, wherein The interruption determination unit for the respective groups determines whether the interruption exists.

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