Vehicle headlight device

Abstract

Vehicle headlight device (1), comprising: a headlight (6, 7) shining in front of a vehicle; a light distribution pattern switching device (13) for switching a light distribution pattern of the headlight between a plurality of light distribution patterns, the plurality of light distribution patterns comprising at least a high beam and a low beam; a detection device (2) for detecting a front vehicle located in front of the vehicle; and a control device (53) for controlling the light distribution pattern switching device based on a detection result of the detection device; where the vehicle headlight device further comprises a curve radius determining device (52) for determining a curve radius of the own vehicle during travel, and if the curve radius of the own vehicle, which was determined by the curve radius determination device, is lower than a predetermined value, the control device prevents the switching of the light distribution pattern of the headlight to a higher level, characterized in that the plurality of light distribution patterns includes the high beam, the low beam and an intermediate high beam between the high beam and the low beam, and the predetermined value comprises a first predetermined value (R1) used to determine the avoidance of switching to the intermediate high beam and a second predetermined value (R2) used to determine the avoidance of switching to the high beam, wherein the second predetermined value differs from the first predetermined value, wherein the second predetermined value is smaller than the first predetermined value, and wherein, if a leading vehicle exists, the first predetermined value is used to determine the avoidance of shifting, and if no leading vehicle exists, the second predetermined value is used to determine the avoidance of shifting.

Description

TECHNICAL FIELD

[0001] The present invention relates to vehicle headlight devices. STATE OF THE ART

[0002] Variable high beam headlight systems (or adaptive headlight systems) are known to improve nighttime driving by illuminating areas other than the vehicles in front (including preceding and oncoming vehicles) with the high beam to ensure a wide forward field of vision.

[0003] Specifically, a variable high beam headlight system is a system that: detects the position of a vehicle in front through image processing information from a vehicle camera; uses a light distribution pattern called an "intermediate high beam" that blanks out an illuminated area while illuminating other areas with high beam; and makes the blanked area follow the vehicle in front, thereby ensuring the forward visibility of the own vehicle over a wide area and making it easier to spot a pedestrian without dazzling the vehicle in front.

[0004] Furthermore, JP 2011 - 255 826 A discloses: the dimming or obscuring of a part of the luminous area by a dimming mechanism arranged in a headlight; and the automatic switching of the light distribution pattern of the headlight to the dipped beam when cornering, regardless of the presence or absence of a vehicle in front. PRIOR ART DOCUMENTSSUMMARY OF THE INVENTIONProblem to be solved by the invention

[0005] However, if the light distribution pattern is switched to the low beam when cornering despite the absence of a preceding vehicle or an oncoming vehicle, as disclosed in JP 2011 - 255 826 A, the forward field of vision may be narrowed, which may frighten a driver of the own vehicle.

[0006] The present invention was conceived based on the circumstances described above. Therefore, an object of the present invention is to provide a vehicle headlight device that can ensure the widest possible field of vision for the driver of the own vehicle while avoiding dazzling the driver or passengers of a preceding vehicle. Means of solving the problem

[0007] According to the invention set forth in claim 1, which achieves the above-described object, a vehicle headlight device comprises: a headlight that illuminates in front of a vehicle; light distribution pattern switching means for switching a light distribution pattern of the headlight between a plurality of light distribution patterns, the plurality of light distribution patterns including at least a high beam and a low beam; detection means for detecting a front vehicle in front of the vehicle; and control means for controlling the light distribution pattern switching means based on a detection result of the detection means.The invention is characterized in that the vehicle headlight device further comprises a turning radius detecting device for detecting a turning radius of the own vehicle during travel, and, when the turning radius of the own vehicle detected by the turning radius detecting device is lower than a predetermined value, the control device prohibits switching the light distribution pattern of the headlight to a higher level.

[0008] With the configuration described above, when the turning radius of the host vehicle is greater than or equal to the predetermined value, the front vehicle is detected by the detection device; based on the detection result, the light distribution pattern switching device is controlled by the control device. Consequently, it is possible to appropriately adjust the light distribution pattern of the headlight. Conversely, when the turning radius of the host vehicle is smaller than the predetermined value, switching the light distribution pattern of the headlight to the higher level is prohibited. Consequently, it is possible to ensure the widest possible field of view without dazzling a driver or passengers of the front vehicle. SHORT DESCRIPTION OF THE DRAWING Fig. 1 is a functional block diagram illustrating the overall structure of a vehicle headlight device according to an embodiment; Fig. 2 shows a schematic view of the structure of a headlight; Fig. 3 shows a schematic view of the light distribution pattern in the intermediate high beam seen from above; Fig. 4 shows a schematic view of the light distribution pattern in the intermediate high beam as seen from a driver's seat; Fig. 5 is a flowchart illustrating a process of an ECU (electronic control unit) for controlling the light distribution patterns of the headlights; and Fig. 6 shows a schematic view of rotation angles of the headlights. EMBODIMENTS OF THE INVENTION

[0009] Hereinafter, a vehicle headlight device 1 according to an embodiment of the present invention will be described with reference to Fig. 1 to 6. As described in Fig. As shown in Figure 1, the vehicle headlight device 1 includes a vehicle camera 2, a steering angle sensor 3, a wheel speed sensor 4, an ECU (electronic control unit) 5, and headlights 6 and 7.

[0010] The vehicle camera 2 is arranged inside a windshield of a vehicle. The vehicle camera 2 captures images in front of the vehicle and sends the data to the ECU 5. The steering angle sensor 3 is an existing sensor for an ESC (Electronic Stability Control) system arranged in a steering mechanism. The steering angle sensor 3 detects a steering angle of the vehicle and sends a steering angle signal indicating the detection results to the ECU 5. The wheel speed sensor 4 is an existing sensor intended for use in an ABS (Anti-lock Braking System). The wheel speed sensor 4 detects a rotational speed of a wheel of the vehicle and sends a wheel speed signal indicating the detection results to the ECU 5.

[0011] The ECU 5 is a control unit for controlling the headlights 6 and 7. Specifically, the ECU 5 includes an image processing section 51, a curve radius determination section 52, and a control section 53. The image processing section 51 processes the data from the vehicle camera 2 and calculates the position of a preceding vehicle or an oncoming vehicle in the form of coordinates. The image processing section 51 also calculates the swivel and rotation angles of the headlights 6 and 7.

[0012] The steering angle detection part 52 calculates a steering angle of the vehicle based on the steering angle signal output from the steering angle sensor 3 and the wheel speed signal output from the wheel speed sensor 4. The control part 53 instructs the headlights 6 and 7 to switch light distribution patterns and rotate based on the calculated turning radius of the vehicle.

[0013] Headlights 6 and 7 are a pair of headlights located on the left and right sides of the vehicle, respectively, to illuminate the front of the vehicle. As shown in Fig. As shown in Figure 2, each of the headlights 6 and 7 includes a light source 11, a lens 12, a shade mechanism 13, and an actuator 14. The light source 11 is a halogen lamp. The shade mechanism 13 includes a plurality of shades (not shown). The shade mechanism 13 forms an intermediate high beam pattern and a low beam pattern according to a command from the control part 53 of the ECU 5 by inserting it into a part of the optical path formed in the headlight to block the light. Furthermore, the shade mechanism 13 forms a high beam pattern by being completely retracted from the optical path. Furthermore, the headlights 6 and 7 have those three light distribution patterns.

[0014] As in the Fig. 3 and Fig. As shown in Figure 4, the intermediate high beam has a concave light distribution pattern that blocks a portion corresponding to the front vehicle to avoid dazzling an occupant of the front vehicle. The left headlight defines a light distribution area 21 having a substantially L-shaped light distribution pattern. The right headlight defines a light distribution area 22 having a substantially mirror-inverted L-shaped light distribution pattern.

[0015] When the left and right headlights simultaneously form the intermediate high beam, a light distribution pattern as shown in the Fig. 3 and Fig. 4. Ideally, it is preferred as shown in Fig. 4 shows that the light beams are arranged such that the positions at the left and right ends of the front vehicle coincide with the positions of the vertical intersection lines of the light beams. Therefore, the position of the front vehicle is always checked and the headlights are swiveled or rotated.

[0016] The intermediate high beam has the same brightness as the high beam, except for the masked or dimmed area. Therefore, if the intermediate high beam were to inadvertently illuminate the vehicle in front, and the vehicle in front were an oncoming vehicle, the light would directly enter the eyes of the driver of the oncoming vehicle, causing dazzling. If the vehicle in front were a preceding vehicle, the light reflected by mirrors would enter the eyes of the driver of the preceding vehicle and / or brightly illuminate the passenger compartment of the preceding vehicle, making it difficult to perceive the outside environment. Therefore, to avoid the above-described problem, it is necessary to calculate the rotation angles when the light distribution pattern of the headlights is switched from the high beam or low beam to the intermediate high beam.

[0017] Furthermore, the actual light distribution pattern is not left-right symmetrical, but rather the left side is more brightly illuminated. However, this is irrelevant to the explanation of the present invention. For simplicity, the explanation is therefore assumed that the light distribution pattern in each figure is symmetrical.

[0018] In addition, headlights 6 and 7 can be switched to high beam, low beam, or ADB mode using a manual switch. ADB (adaptive forward lighting) refers to a variable headlight high beam system.

[0019] The high beam and low beam are the same as in the prior art. The left and right headlights are switched to high beam or low beam simultaneously. ADB mode is an automatic switching mode in which the control unit 53 of the ECU 5 automatically switches the left and right headlights to high beam or switches the left and right headlights individually to intermediate high beam or low beam.

[0020] At the point where the aperture mechanism 13 inserts and removes the apertures, as shown in Fig. 2, the up-down and left-right relationship is reversed by the lens 12. Thus, when the aperture mechanism 13 covers the lower side of the optical path, as shown in Fig. 2, the upper side of the luminous area is masked. This means that by masking a predetermined lower area of ​​the optical path, it is possible to realize a light distribution pattern that is Fig. 3 and Fig. 4 is shown.

[0021] The actuator 14, in accordance with a command from the control part 53 of the ECU 5, controls the entire headlight to rotate about a rotation axis. Specifically, based on data from the vehicle camera 2, the actuator 14 controls the headlight to rotate to prevent the illumination area defined by the intermediate high beam from illuminating a vehicle ahead, which could dazzle a driver or passenger of the vehicle ahead. At this time, a reference optical axis position of each headlight is determined using command information (command values ​​of rotation angles) from the control part 53 of the ECU 5 to the actuators 14 of the headlights 6 and 7.

[0022] The control and operation of the vehicle headlight device 1 according to the present embodiment will be described below. Fig. The flowchart shown in Figure 5 illustrates a process of the ECU 5 that is executed when the headlights are set to ADB mode and turned on. The data initialization and initialization processes, such as a mode determination process, are omitted. The "START" in Fig. 5 indicates a state in which this initialization process has already been completed.

[0023] First, the turning radius determining part 52 of the ECU 5 calculates the turning radius of the vehicle based on the steering angle signal from the steering angle sensor 3 and the wheel speed signal from the wheel speed sensor 4 (Step-1; hereinafter abbreviated as S-1; other steps are abbreviated in the same way). [Case where a front vehicle exists]

[0024] Subsequently, the control part 53 of the ECU 5 determines whether a front vehicle is present or not based on the information from the in-vehicle camera 2 (S-2). If a front vehicle is present (S-2: YES), the image processing part 51 of the ECU 5 performs image processing on the information from the in-vehicle camera 2 and calculates the left and right coordinates of the front vehicle based on, for example, the taillights of a preceding vehicle or the headlights of an oncoming vehicle. Furthermore, based on the calculated coordinates, the image processing part 51 calculates rotation angles for causing the headlights to follow the front vehicle (S-4).

[0025] Furthermore, in the present embodiment, the headlights are only rotated to follow the position of the vehicle ahead when the light distribution patterns of the headlights are in the intermediate high beam. However, in S-4, the calculation of the rotation angles is performed independently of the light distribution patterns of the headlights. This is because the rotation angles are needed later to determine whether or not the light distribution patterns need to be switched from the low beam to the intermediate high beam in S-8, and whether the light distribution patterns need to be switched from the high beam to the intermediate high beam in S-9.

[0026] Subsequently, in step S-5, the control section 53 compares the curve radius calculated in step S-1 with a predetermined value R1. Here, R1 is equal to 150 m. In the light distribution control, if a leading vehicle exists, curves with a curve radius greater than or equal to 150 m are treated as straight.

[0027] When the turning radius is smaller than the specified value R1 (S-5: YES), the current light distribution patterns of headlights 6 and 7 are determined. The previous command signal to headlights 6 and 7, stored in the ECU 5, can be used for this purpose. Consequently, it is possible to know whether the high beam, intermediate high beam, or low beam constitutes the current light distribution pattern. The case where the turning radius is greater than or equal to the specified value R1 (S-5: NO) will be described later.

[0028] In the following step S-7, it is determined whether the determined light distribution patterns are the low beam or not. In addition, this determination is made individually for the left and right headlights. If the light distribution patterns are the low beam (S-7: YES), the process returns to S-1.

[0029] The case where the light distribution pattern is not the low beam (S-7: NO), that is, the high beam or the intermediate high beam, and the case where the turning radius is greater than or equal to the predetermined value R1 will now be described. In these cases, a comparison is made between the turning angle toward the outside of the vehicle for the left and right headlights and a predetermined value. In addition, the case where the light distribution pattern is the high beam in S-7 is a case where the light distribution pattern was initially set or held at the high beam in S-11 because no vehicle ahead exists, and then the result of the determination in S-2 becomes YES only after the appearance of a vehicle ahead.

[0030] In the ECU 5, the angles of rotation are indicated with a symbol used for the image-processed coordinates, as shown in Fig. 6. This means that if the angles pointing towards the front of the vehicle are zero, the angles inclined to the left become positive and the angles inclined to the right become negative. In addition, Fig. 6 the left headlight is marked 6 and the right headlight is marked 7.

[0031] The “ROTATION ANGLE TOWARDS THE OUTSIDE OF THE VEHICLE” in the box of S-8 in the flow chart indicates the rotation angle toward the positive side in the case of headlight 6 and the rotation angle toward the negative side in the case of headlight 7.

[0032] Accordingly, if the rotation angle of the left headlight 6 is less than or equal to the positive predetermined value (S-8: YES), the light distribution pattern of the left headlight 6 is set or maintained to be in the intermediate high beam (S-9). Furthermore, if the rotation angle of the right headlight 7 is greater than or equal to (or less than or equal in absolute value) the predetermined value (S-8: YES), the light distribution pattern of the right headlight 7 is set or maintained to be in the intermediate high beam (S-9).

[0033] Furthermore, if the rotation angle of the left headlight 6 is greater than the specified value (S-8: NO), the light distribution pattern of the left headlight 6 is set to the high beam (S-10). Furthermore, if the rotation angle of the right headlight 7 is smaller than (or greater in absolute value) the specified value (S-8: NO), the light distribution pattern of the right headlight 7 is set to the low beam (S-10). In the low beam, rotation for tracking the vehicle ahead by the headlights is not performed, and the optical axes are reset to their original positions.

[0034] After S-9 and S-10, the process returns to S-1. In addition, Fig. 6, when the rotation angle is toward the inside of the vehicle, that is, when the rotation angle is positive in the case of the right headlight and negative in the case of the left headlight, the switching of the light distribution pattern is not executed.

[0035] To explain this process with reference to an actual situation, if there is no vehicle in front and the light distribution patterns are thus switched to the high beam, the light distributions are controlled to switch to the intermediate high beam or low beam when a vehicle in front appears. In this case, since steps S-1 to S-9 and S-10 are executed in a very short time, the driver or passenger of the vehicle in front will not be dazzled.

[0036] Furthermore, in a curve with a curve radius smaller than the specified curve radius, if the current light distribution pattern is low beam, the low beam is maintained. Consequently, the driver or passenger of the vehicle in front is not dazzled.

[0037] In a curve with a curve radius smaller than the specified curve radius, if the light distribution patterns are high beam or intermediate high beam, the latter are controlled according to the calculated rotation angles to switch to intermediate high beam or low beam. Consequently, it is possible to ensure the largest possible forward visibility without dazzling the driver or passengers of a vehicle ahead. [Case where no front vehicle exists]

[0038] If there is no vehicle in front in S-2 (S-2: NO), the curve radius calculated in S-1 is compared with a predefined value R2 (S-3). R2 is equal to 100 m. For light distribution control, if there is no vehicle in front, curves with a curve radius greater than or equal to 100 m are considered straight.

[0039] If the turning radius is smaller than the specified value R2 (S-3: YES), switching of the light distribution patterns is not performed, and the light distribution patterns are thus maintained; then the process returns to S-1. If the turning radius is greater than or equal to the specified value R2 (S-3: NO), the light distribution patterns of the left or right headlights are set or maintained to be in the high beam (S-11); then the process returns to S-1.

[0040] To illustrate this point in the context of an actual situation, when the vehicle is traveling on a straight road (S-3: NO) with no vehicle in front (S-2: NO), the headlights are controlled to the high beam mode (S-11). From this state, even when the vehicle enters a curve and the curve radius becomes smaller than the specified value R2 (S-3: YES), the light distribution patterns are maintained in the high beam mode. Consequently, the forward field of vision is not restricted, contributing to safe driving.

[0041] The following describes characteristic processes according to the present embodiment that are executed when the vehicle, after partially negotiating the curve, is brought from the state where a leading vehicle exists (S-2: YES) to a state where no leading vehicle exists (S-2: NO). In most cases, when the vehicle is traveling on a straight road while following a leading vehicle (S-5: NO), the left and right headlights are switched to the intermediate high beam (S-8: YES, S-9).

[0042] When the vehicle enters a curve, if there is a branch on the way through the curve and the vehicle ahead is turning left, there is a high probability that the right headlight will be kept in the intermediate high beam and the left headlight will be switched to the low beam (S-8: NO, S-10). Since the vehicle is then placed in a state where there is no vehicle ahead, S-2 will be NO in the next round and the curve radius will be compared with R2 (S-3).

[0043] At this time, if the curve radius is smaller than R2, the light distribution pattern is not switched but maintained even if there is no vehicle in front. For example, the right headlight is kept in intermediate high beam and the left headlight is kept in low beam.

[0044] If the light distribution patterns were switched to the high beam while cornering, the field of view would suddenly expand, which could cause discomfort to the driver. Furthermore, in a curve, compared to a straight road, a vehicle ahead would not enter the camera's field of view and thus would not be detected until the vehicle ahead was immediately in front of the vehicle. Therefore, if the detection status of the preceding or oncoming vehicle frequently changes, the light distribution patterns would switch frequently, which could be disturbing. Thus, if the curve radius is smaller than R2, even if there is no vehicle ahead, the previously set light distribution patterns are determined to be maintained.

[0045] Since the current light distribution patterns are maintained in curves where the turning radius is smaller than the specified turning radius, even if there is no vehicle in front, the driver of the own vehicle does not feel uncomfortable or disturbed.

[0046] Furthermore, the predetermined value R2 is set to be smaller than the predetermined value R1. In the present embodiment, as described above, the predetermined value R2 is 100 m, and the predetermined value R1 is 150 m. If there is no front vehicle, no one would be dazzled, so the condition for raising the light distribution pattern to the high beam is relaxed compared to the case where there is a front vehicle.

[0047] As described above, even if the leading vehicle disappears partially through the curve where the turning radius is smaller than R2, the vehicle travels to the curve exit while maintaining the light distribution pattern. After reaching the curve exit or a straight road, the turning radius is increased. However, in this case, the absence of a leading vehicle is determined based on long-distance detection by the in-vehicle camera 2. Therefore, the possibility of the light distribution patterns being switched frequently is reduced; thus, it is OK to allow switching of the light distribution patterns in the state where the turning radius is smaller than the predetermined value R1, which is used in the case of a leading vehicle (S-3: NO).Accordingly, the preset value R2 is set to less than the preset value R1, and the light distribution patterns are raised to the high beam early at the exit of the curve when there is no vehicle in front, thereby giving priority to expanding the field of view.

[0048] As described above, regardless of the presence or absence of a vehicle in front, control is performed during cornering so as not to switch the light distribution patterns to a higher level, but at least to maintain or switch them to a low level. In addition, "switching to a higher level" refers to switching a light distribution pattern to a wider illumination range, for example, switching from the intermediate high beam or low beam to the high beam, or switching from the low beam to the intermediate high beam. "Switching to a low level" also refers to switching the light distribution pattern to a narrower or shorter illumination range, for example, switching from the intermediate high beam or high beam to the low beam, or switching from the high beam to the intermediate high beam.

[0049] As is clear from the above explanation, according to the present embodiment, a vehicle headlight device comprises: a headlight (6, 7) that illuminates in front of the vehicle; light distribution pattern switching means (the shade mechanism 13) for switching the light distribution pattern of the headlight between a plurality of light distribution patterns including at least the high beam and the low beam; detection means (the in-vehicle camera 2) for detecting a front vehicle located in front of the vehicle; and control means (the control part 53) for controlling the light distribution pattern switching means based on a detection result by the detection means. The device further comprises turning radius detection means (the turning radius detection part 52) ​​for detecting the turning radius of the subject vehicle during travel.If the curve radius of the own vehicle, which is determined by the curve radius determination device, is smaller than a predetermined value, the control device prevents the light distribution pattern from switching to a higher level.

[0050] The turning radius determining device according to the present embodiment calculates the turning radius based on the steering angle signal output from a steering angle sensor 3 and the wheel speed signal output from a wheel speed sensor 4. With this configuration, it is possible to accurately calculate the turning radius.

[0051] Furthermore, according to the present embodiment, the predetermined value includes a first predetermined value (R1) used to determine whether switching to the intermediate high beam is avoided, and a second predetermined value (R2) different from the first predetermined value (R1) used to determine whether switching to the high beam is avoided. The second predetermined value (R2) is smaller than the first predetermined value (R1).

[0052] Further, according to the present embodiment, when the presence of a vehicle in front is detected by the detecting means, the control means sets the light distribution pattern of left and right headlights of the vehicle to the low beam or the intermediate high beam which is between the high beam and the low beam via the light distribution pattern switching means.

[0053] The present invention is not limited to the above-described embodiment and its modifications. It should be understood that various modifications may be made without departing from the spirit of the invention.

[0054] For example, the explanation of the present embodiment is based on a preceding vehicle. However, by configuring the in-vehicle camera 2 to detect the headlights of an oncoming vehicle, it is also possible to similarly detect the left and right ends of an oncoming vehicle and apply the control of the above embodiment.

[0055] Furthermore, the vehicle camera 2 can be realized by an existing camera that is used for other purposes, for example in a collision avoidance system.

[0056] In the embodiment described above, the headlight light sources are halogen lamps. However, the headlight light sources can also be LED lamps, HID lamps (HID is a registered trademark), or other types of light sources.

[0057] In the above-described embodiment, the reference position of the optical axis of each headlight is determined using the command information from the ECU 5 to the actuators 14 of the headlights 6 and 7. However, the reference position can also be determined by image processing the information from the vehicle camera 2 using the command information to the actuators 14.

[0058] The above-described embodiment is described based on the assumption that the vehicle travels on the left side, as is the case in Japan and the United Kingdom. However, the invention can also be applied to cases where the vehicle travels on the right.

[0059] In addition, in S-8, the preset value against which the rotation angles are compared can be set differently for the left and right headlights. For example, the right headlight can be switched to the intermediate high beam or held there when the rotation angle to the outside of the vehicle is less than or equal to 15°; the left headlight can be switched to the intermediate high beam or held there when the rotation angle to the outside of the vehicle is less than or equal to 5°.

[0060] In the above-described embodiment, the predetermined values ​​R1 and R2 against which the curve radius is compared are set to 150 m and 100 m, respectively. However, the predetermined values ​​R1 and R2 can also be set to other values ​​depending on the vehicle type.

[0061] In the above-described embodiment, the intermediate high beam pattern is substantially L-shaped or substantially mirror-inverted L-shaped. However, the intermediate high beam pattern is not limited to these shapes and may have any other shape that includes a blanked-off portion.

[0062] In the above-described embodiment, the turning radius is calculated based on the output signals from the steering angle sensor and wheel speed sensor. However, the turning radius can also be calculated based on information from a vehicle navigation system or an image processing process of white lines on the road. LIST OF REFERENCE SYMBOLS 1 vehicle headlight device 2 vehicle cameras 6, 7 headlights 13 Aperture mechanism 52 Curve radius determination part 53 Control unit

Claims

[1] Vehicle headlight device (1), comprising: a headlight (6, 7) shining in front of a vehicle; a light distribution pattern switching device (13) for switching a light distribution pattern of the headlight between a plurality of light distribution patterns, the plurality of light distribution patterns comprising at least a high beam and a low beam; a detection device (2) for detecting a front vehicle located in front of the vehicle; and a control device (53) for controlling the light distribution pattern switching device based on a detection result of the detection device; where the vehicle headlight device further comprises a curve radius determining device (52) for determining a curve radius of the own vehicle during travel, and if the curve radius of the own vehicle, which was determined by the curve radius determination device, is lower than a predetermined value, the control device prevents the switching of the light distribution pattern of the headlight to a higher level, characterized by , that the plurality of light distribution patterns includes the high beam, the low beam and an intermediate high beam between the high beam and the low beam, and the predetermined value comprises a first predetermined value (R1) used to determine the avoidance of switching to the intermediate high beam and a second predetermined value (R2) used to determine the avoidance of switching to the high beam, wherein the second predetermined value differs from the first predetermined value, wherein the second predetermined value is smaller than the first predetermined value, and wherein, if a leading vehicle exists, the first predetermined value is used to determine the avoidance of shifting, and if no leading vehicle exists, the second predetermined value is used to determine the avoidance of shifting. [2] A vehicle headlight device according to claim 1, further characterized by , that the curve radius determining device calculates the curve radius based on a steering angle of the host vehicle detected by a steering angle sensor (3) and a rotational speed of a wheel of the host vehicle detected by a wheel speed sensor (4). [3] A vehicle headlight device according to claim 1 or 2, further characterized by , that, when the presence of a vehicle in front is detected by the detection device, the control device switches the light distribution pattern of the left and right headlights of the vehicle to the low beam or the intermediate high beam by means of the light distribution pattern switching device. [4] A vehicle headlight device according to claim 1, wherein, when the turning radius of the own vehicle detected by the turning radius detecting means is smaller than the second predetermined value (R2), the control means controls the light distribution pattern switching means not to execute the switching of the light distribution patterns.

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