Light distribution control device, vehicle lamp system, and computer program

Abstract

A light distribution control device 4 controls the formation of a light distribution pattern PTN by a vehicle lamp 2 that is installed on a saddle-ridden vehicle 100. The light distribution control device 4 controls the vehicle lamp 2 to change the light distribution pattern PTN in association with the combination of a bank angle for the saddle-ridden vehicle 100 and a surrounding brightness that is the brightness of the surrounding environment of the saddle-ridden vehicle 100.

Description

Light distribution control device, vehicle lighting system, and computer program

[0001] The present invention relates to a light distribution control device, a vehicle lighting system, and a computer program.

[0002] Patent Document 1 describes a vehicle lamp provided on a saddle-type vehicle that travels around a corner by tilting the vehicle body in the turning direction, and adds a side light distribution pattern diagonally above the high-beam light distribution pattern when the saddle-type vehicle banks.

[0003] International Publication No. 2022 / 185887

[0004] As a result of intensive studies on the formation of the light distribution pattern by the vehicle lamp mounted on the saddle-type vehicle, the inventors have found a technique for improving the safety of vehicle driving, such as improving the visibility of the driver of the saddle-type vehicle and suppressing glare received by the driver of the preceding vehicle.

[0005] The present invention has been made in view of such a situation, and one of its objects is to provide a technique for improving the safety of vehicle driving.

[0006] In order to solve the above problems, an aspect of the present invention is a light distribution control device that controls the formation of a light distribution pattern by a vehicle lamp mounted on a saddle-type vehicle. This light distribution control device controls the vehicle lamp so as to change the light distribution pattern according to the combination of the bank angle of the saddle-type vehicle and the ambient illuminance, which is the illuminance of the surrounding environment of the saddle-type vehicle.

[0007] Another aspect of the present invention is a vehicle lighting system. This vehicle lighting system includes a vehicle lamp mounted on a saddle-type vehicle, an attitude sensor that detects the bank angle of the saddle-type vehicle, an illuminance sensor that detects the illuminance of the surrounding environment of the saddle-type vehicle, and the light distribution control device of the above aspect.

[0008] Another aspect of the present invention is a computer program executed by a light distribution control device that controls the formation of a light distribution pattern by a vehicle light fixture mounted on a saddle-type vehicle. This computer program causes the light distribution control device to execute a function that controls the vehicle light fixture to change the light distribution pattern according to a combination of the bank angle of the saddle-type vehicle and the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle.

[0009] Furthermore, any combination of the above components, as well as conversions of the expression of the present invention between methods, apparatus, systems, etc., are also valid embodiments of the present invention.

[0010] According to the present invention, the safety of vehicle operation can be improved.

[0011] This is a block diagram of a vehicle lighting system according to an embodiment. It is a schematic diagram of a light distribution pattern that can be formed by the vehicle lighting. Figures 3(A), 3(B), 3(C), 3(D), 3(E), and 3(F) illustrate an example of light distribution control performed by a light distribution control device.

[0012] The present invention will be described below with reference to the drawings, based on preferred embodiments. The embodiments are illustrative and not limiting, and not all features or combinations thereof described in the embodiments are necessarily essential to the invention. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and redundant explanations are omitted as appropriate. Furthermore, the scale and shape of each part shown in each figure are set for convenience to facilitate explanation and are not to be interpreted restrictively unless otherwise specified. In addition, when terms such as "first," "second," etc. are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are used to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from the drawings.

[0013] Figure 1 is a block diagram of a vehicle lighting system 1 according to an embodiment. In Figure 1, the components of the vehicle lighting system 1 are depicted as functional blocks. These functional blocks are realized in hardware configurations using elements and circuits such as the CPU and memory of a computer, and in software configurations using computer programs, etc. It will be understood by those skilled in the art that these functional blocks can be realized in various forms through combinations of hardware and software.

[0014] The vehicle lighting system 1 comprises a vehicle lighting fixture 2, a light distribution control device 4, a posture sensor 6, and an illuminance sensor 18. These are mounted on a saddle-type vehicle 100 such as a motorcycle. The mechanisms of the vehicle lighting fixture 2, light distribution control device 4, posture sensor 6, and illuminance sensor 18 may all be housed in the same housing, or some of the mechanisms may be provided outside the housing. For example, each mechanism is housed in a lamp chamber. The lamp chamber is partitioned by a lamp body having an opening on the front side of the vehicle and a light-transmitting cover attached to cover the opening of the lamp body. The light distribution control device 4, posture sensor 6, and illuminance sensor 18 may be located outside the lamp chamber, for example, on the body of the saddle-type vehicle 100. For example, the light distribution control device 4 may be composed entirely or partially of a vehicle ECU. The posture sensor 6 may be integrated into the vehicle ECU.

[0015] The vehicle lamp 2 is, for example, a variable-distribution lamp capable of illuminating the front area of ​​a saddle-type vehicle 100 with a visible light beam L1 having a variable intensity distribution. The vehicle lamp 2 can individually change the illuminance of the light illuminating multiple individual areas R arranged in the front area. In other words, the vehicle lamp 2 can illuminate the space in front of the vehicle with light of different intensity depending on the location, i.e., the individual areas R. The multiple individual areas R are arranged, for example, in a matrix. The vehicle lamp 2 receives information from the light distribution control device 4 to instruct the light distribution pattern PTN and emits a visible light beam L1 having an intensity distribution corresponding to the light distribution pattern PTN. As a result, the light distribution pattern PTN is formed in front of the vehicle. The light distribution pattern PTN is understood as the two-dimensional illuminance distribution of the illumination pattern 902 that the vehicle lamp 2 forms on a virtual vertical screen 900 in front of the vehicle.

[0016] The configuration of the variable-beam lamp used in the vehicle lighting fixture 2 is not particularly limited and includes, for example, a plurality of light sources arranged in a matrix and a lighting circuit that independently drives and lights each light source. Preferred examples of light sources include semiconductor light sources such as LEDs (light-emitting diodes), LDs (laser diodes), and organic or inorganic ELs (electroluminescent). Each individual region R is associated with each light source, and light is individually irradiated from each light source to each individual region R. The resolution of the vehicle lighting fixture 2, in other words, the light distribution resolution, is, for example, several pixels to about 2 million pixels. The resolution of the vehicle lighting fixture 2 may also be, for example, about 5 pixels to several tens of pixels. The resolution of the vehicle lighting fixture 2 means the number of unit regions in the light distribution pattern PTN whose illuminance can be independently changed.

[0017] Figure 2 is a schematic diagram of the light distribution pattern PTN that can be formed by the vehicle lamp 2. The vehicle lamp 2 of this embodiment can form a light distribution pattern LP for low beam, a light distribution pattern HP for high beam, a left additional light distribution pattern LAP, and a right additional light distribution pattern RAP.

[0018] The low-beam light distribution pattern LP and the high-beam light distribution pattern HP are formed or projected within the ranges specified by law. The low-beam light distribution pattern LP is mainly formed below the H-H line in the virtual vertical screen 900. The upper end of the low-beam light distribution pattern LP may extend above the H-H line. The high-beam light distribution pattern HP is formed above the low-beam light distribution pattern LP. The left additional light distribution pattern LAP is formed in the region including the area above the left end of the high-beam light distribution pattern HP. The right additional light distribution pattern RAP is formed in the region including the area above the right end of the high-beam light distribution pattern HP.

[0019] As an example, the low-beam light distribution pattern LP includes a first low-beam section LP1, a second low-beam section LP2, a third low-beam section LP3, and a fourth low-beam section LP4, arranged in order from left to right in the vehicle width direction. When the saddle-type vehicle 100 is not banked, the first low-beam section LP1 and the second low-beam section LP2 are formed in the region to the left of the V-V line in the virtual vertical screen 900, and the third low-beam section LP3 and the fourth low-beam section LP4 are formed in the region to the right of the V-V line. The illuminance of each section can be changed independently.

[0020] The high beam light distribution pattern HP includes a first high beam section HP1, a second high beam section HP2, a third high beam section HP3, a fourth high beam section HP4, a fifth high beam section HP5, and a sixth high beam section HP6, arranged in order from left to right in the vehicle width direction. When the saddle-type vehicle 100 is not banked, the first high beam section HP1, the second high beam section HP2, and the third high beam section HP3 are formed in the area to the left of the V-V line, while the fourth high beam section HP4, the fifth high beam section HP5, and the sixth high beam section HP6 are formed in the area to the right of the V-V line. The illuminance of each section can be changed independently.

[0021] The left additional light distribution pattern LAP and the right additional light distribution pattern RAP are each composed of a single part, for example. Furthermore, the left additional light distribution pattern LAP is formed above the first high beam section HP1 and the second high beam section HP2, for example. The right additional light distribution pattern RAP is formed above the fifth high beam section HP5 and the sixth high beam section HP6, for example.

[0022] Furthermore, the variable-beam lamp may include a matrix-type pattern forming device such as a DMD (Digital Mirror Device) or liquid crystal device, or a scanning optical type pattern forming device that scans the area in front of the vehicle with light from a light source, in order to form an illuminance distribution corresponding to the light distribution pattern PTN. In addition, the vehicle lamp 2 may include separate lamps for forming the low-beam light distribution pattern LP, the high-beam light distribution pattern HP, the left additional light distribution pattern LAP, and the right additional light distribution pattern RAP. The number of divisions of the low-beam light distribution pattern LP and the high-beam light distribution pattern HP, as well as the arrangement of each part, can be changed as appropriate. In addition, the left additional light distribution pattern LAP and the right additional light distribution pattern RAP may include multiple parts whose illuminance can be changed independently.

[0023] Returning to Figure 1, the light distribution control device 4 controls the formation of the light distribution pattern PTN by the vehicle lamp 2. In this embodiment, the light distribution control device 4 controls the vehicle lamp 2 to dynamically change the light distribution pattern PTN according to the combination of the bank angle of the saddle-type vehicle 100 and the ambient illuminance. The light distribution control device 4 can be configured as a digital processor, for example, consisting of a combination of a microcontroller including a CPU and a software program. The light distribution control device 4 may also be configured as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specified IC).

[0024] The light distribution control device 4 includes a control unit 8, which is composed of a CPU and the like, and a storage medium 10, which is composed of memory and storage. The control unit 8 includes, for example, a pattern determination unit 12 and a lamp control unit 14. The storage medium 10 stores computer programs and the like that are executed by the light distribution control device 4, or more specifically, the control unit 8. Each part included in the control unit 8 operates by having its constituent integrated circuit execute the program stored in the storage medium 10.

[0025] The control unit 8 can receive signals transmitted from the illuminance sensor 18. The illuminance sensor 18 detects the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle 100, and transmits a signal indicating the detection result to the control unit 8. The illuminance sensor 18 can be configured as a known illuminometer, camera, or the like. If the illuminance sensor 18 is configured as a camera, the ambient illuminance can be detected from the average pixel value in the image captured by the camera. If the illuminance sensor 18 is positioned on the vehicle body, the illuminance sensor 18 may be configured as an on-board camera. The control unit 8 can also receive signals transmitted from the attitude sensor 6. The attitude sensor 6 detects the tilt of the saddle-type vehicle 100 in the left-right direction, that is, the bank angle of the saddle-type vehicle 100, and transmits a signal indicating the detection result to the control unit 8. The attitude sensor 6 can be configured as, for example, a known inertial measurement unit (IMU). The ambient illuminance information and bank angle information sent to the control unit 8 are acquired by the pattern determination unit 12.

[0026] The pattern determination unit 12 determines the illuminance (i.e., pattern illuminance) of each part of the low beam light distribution pattern LP (first low beam portion LP1 to fourth low beam portion LP4), the high beam light distribution pattern HP (first high beam portion HP1 to sixth high beam portion HP6), the left additional light distribution pattern LAP, and the right additional light distribution pattern RAP, according to the combination of the bank angle of the saddle-type vehicle 100 and the ambient illuminance, and determines the light distribution pattern PTN to be formed. For example, a conversion table is created in advance and stored in the storage medium 10, which associates the bank angle, ambient illuminance, and the illuminance of each part of the light distribution pattern PTN. The pattern determination unit 12 uses this conversion table to determine the light distribution pattern PTN. The pattern determination unit 12 sends the information of the determined light distribution pattern PTN to the lamp control unit 14.

[0027] The lamp control unit 14 instructs the vehicle lamp 2 to form a light distribution pattern PTN. The lamp control unit 14 is composed of, for example, a known LED driver module (LDM). If the dimming method of the light source of the vehicle lamp 2 is analog dimming, the lamp control unit 14 adjusts the DC level of the drive current flowing to the light source. If the dimming method of the light source is PWM (Pulse Width Modulation) dimming, the lamp control unit 14 adjusts the average level of the drive current by switching the current flowing to the light source and adjusting the ratio of the on period, i.e., the duty cycle. Furthermore, if the vehicle lamp 2 has a DMD, the lamp control unit 14 controls the on / off switching of each mirror element constituting the DMD. If the vehicle lamp 2 has a liquid crystal device, the lamp control unit 14 controls the light transmittance of the liquid crystal device. As a result, the light distribution pattern PTN is formed in front of the saddle-type vehicle 100.

[0028] Next, the operation of the light distribution control device 4 will be explained. Figures 3(A), 3(B), 3(C), 3(D), 3(E), and 3(F) illustrate an example of light distribution control performed by the light distribution control device 4. In Figures 3(A) to 3(F), the numbers indicated in each light distribution pattern represent the illuminance ratio when the maximum illuminance of the light emitted by the vehicle lamp 2 is set to 100%.

[0029] (Control of additional light distribution pattern) When the bank angle is within a predetermined first bank angle range BR1 which is equal to or greater than a predetermined first bank threshold Thb1, and the ambient illuminance is equal to or greater than a predetermined illuminance threshold Thi, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the additional light distribution pattern on the side on which the saddle-type vehicle 100 is tilted compared to when the bank angle is less than the first bank threshold Thb1. Furthermore, when the bank angle is within the first bank angle range BR1 and the ambient illuminance is less than the illuminance threshold Thi, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the additional light distribution pattern compared to when the bank angle is within the first bank angle range BR1 and the ambient illuminance is equal to or greater than the illuminance threshold Thi.

[0030] Furthermore, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the additional light distribution pattern when the bank angle is within a predetermined second bank angle range BR2 which is greater than the first bank angle range BR1 and the ambient illuminance is greater than or equal to the illuminance threshold Thi, compared to when the bank angle is within the first bank angle range BR1 and the ambient illuminance is greater than or equal to the illuminance threshold Thi. Furthermore, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the additional light distribution pattern when the bank angle is within the second bank angle range BR2 and the ambient illuminance is less than the illuminance threshold Thi, compared to when the bank angle is within the first bank angle range BR1 and the ambient illuminance is less than the illuminance threshold Thi.

[0031] Furthermore, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the additional light distribution pattern when the bank angle is within the second bank angle range BR2 and the ambient illuminance is equal to or greater than the illuminance threshold Thi, compared to when the bank angle is within the first bank angle range BR1 and the ambient illuminance is less than the illuminance threshold Thi.

[0032] Hereafter, ambient illuminance of 10 or greater than the illuminance threshold Thi will be referred to as the high illuminance range IRH (or first illuminance range), and illuminance of 10 or less than the illuminance threshold Thi will be referred to as the low illuminance range IRL (or second illuminance range). Furthermore, when the bank angle is less than the first bank threshold Thb1, it is referred to as a non-bank state. The non-bank state is divided into a non-bank high illuminance state where the ambient illuminance is within the high illuminance range IRH, and a non-bank low illuminance state where the ambient illuminance is within the low illuminance range IRL. The non-bank high illuminance state is shown in Figure 3(A). The non-bank low illuminance state is shown in Figure 3(B).

[0033] Furthermore, when the bank angle is greater than or equal to the first bank threshold Thb1, it is called a bank state. Bank states are divided into shallow bank states, where the bank angle is within the first bank angle range BR1, and deep bank states, where the bank angle is within the second bank angle range BR2. For example, the second bank angle range BR2 is the range greater than or equal to a predetermined second bank threshold Thb2, which is greater than the first bank threshold Thb1. Also, the first bank angle range BR1 is the range greater than or equal to the first bank threshold Thb1 and less than the second bank threshold Thb2.

[0034] Shallow bank states are divided into shallow bank high-illuminance states where the ambient illuminance is within the high-illuminance range IRH, and shallow bank low-illuminance states where the ambient illuminance is within the low-illuminance range IRL. The shallow bank high-illuminance state is shown in Figure 3(C). The shallow bank low-illuminance state is shown in Figure 3(D). Deep bank states are divided into deep bank high-illuminance states where the ambient illuminance is within the high-illuminance range IRH, and deep bank low-illuminance states where the ambient illuminance is within the low-illuminance range IRL. The deep bank high-illuminance state is shown in Figure 3(E). The deep bank low-illuminance state is shown in Figure 3(F).

[0035] In this embodiment, as an example, when the saddle-type vehicle 100 is in a non-bank high-illumination state (<Thb1, IRH) as shown in Figure 3(A), and when the saddle-type vehicle 100 is in a non-bank low-illumination state (<Thb1, IRL) as shown in Figure 3(B), a predetermined left additional light distribution pattern LAP and a right additional light distribution pattern RAP are formed at 0 illuminance. 0 illuminance also includes 0% illuminance. In other words, in the non-bank state, an additional light distribution pattern may not be formed.

[0036] Furthermore, as shown in Figure 3(C), when the saddle-type vehicle 100 is tilted to the left and in a shallow bank high-illumination state (BR1, IRH), a left-side additional light distribution pattern LAP with a first illuminance higher than the zero illuminance is formed. The first illuminance is, for example, 30%. Also, as shown in Figure 3(D), when the saddle-type vehicle 100 is tilted to the left and in a shallow bank low-illumination state (BR1, IRL), a left-side additional light distribution pattern LAP with a second illuminance higher than the first illuminance is formed. The second illuminance is, for example, 45%.

[0037] Furthermore, as shown in Figure 3(E), when the saddle-type vehicle 100 is tilted to the left and in a deep bank high-illumination state (BR2, IRH), a left-side additional light distribution pattern LAP with a third illuminance higher than the first illuminance is formed. The third illuminance is, for example, 50%. Also, as shown in Figure 3(F), when the saddle-type vehicle 100 is tilted to the left and in a deep bank low-illumination state (BR2, IRL), a left-side additional light distribution pattern LAP with a fourth illuminance higher than the second illuminance is formed. The fourth illuminance is, for example, 75%.

[0038] Furthermore, as shown in Figure 3(E), the third illuminance (50% for example) of the left additional light distribution pattern LAP formed when the saddle-type vehicle 100 is in a deep bank high-illuminance state (BR2, IRH) is higher than the second illuminance (45% for example) of the left additional light distribution pattern LAP formed when the saddle-type vehicle 100 is in a shallow bank low-illuminance state (BR1, IRL), as shown in Figure 3(D).

[0039] (Control of the high beam light distribution pattern HP) When the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the high illuminance range IRH, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the area on the side where the saddle-type vehicle 100 is tilted in the high beam light distribution pattern HP compared to when the bank angle is less than the first bank threshold Thb1 and the ambient illuminance is within the high illuminance range IRH. Furthermore, when the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the low illuminance range IRL, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the high beam light distribution pattern HP compared to when the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the high illuminance range IRH.

[0040] Furthermore, when the bank angle is within the second bank angle range BR2, the light distribution control device 4 controls the vehicle lamp 2 to lower the illuminance of at least a portion of the area on the side opposite to the side to which the saddle-type vehicle 100 is tilted in the high beam light distribution pattern HP compared to when the bank angle is less than the second bank angle range BR2.

[0041] In this embodiment, as an example, as shown in Figure 3(A), when the saddle-type vehicle 100 is in a non-bank high-illumination state (<Thb1, IRH), a high-beam light distribution pattern HP is formed in which, for example, the first high-beam portion HP1 at the left end has a fifth illuminance. The fifth illuminance is, for example, 15%. Also, as shown in Figure 3(C), when the saddle-type vehicle 100 is tilted to the left and in a shallow-bank high-illumination state (BR1, IRH), a high-beam light distribution pattern HP is formed in which the first high-beam portion HP1 has a sixth illuminance that is higher than the fifth illuminance. The sixth illuminance is, for example, 50%. Also, as shown in Figure 3(D), when the saddle-type vehicle 100 is tilted to the left and in a shallow-bank low-illumination state (BR1, IRL), a high-beam light distribution pattern HP is formed in which the first high-beam portion HP1 has a seventh illuminance that is higher than the sixth illuminance. The seventh illuminance is, for example, 70%. The illumination of the second high beam section HP2 and the third high beam section HP3, located on the left side of the saddle-type vehicle 100, is adjusted in the same manner as the illumination of the first high beam section HP1.

[0042] Furthermore, as shown in Figure 3(A), when the saddle-type vehicle 100 is in a non-bank high-illumination state (<Thb1, IRH), as shown in Figure 3(C), when the saddle-type vehicle 100 is tilted to the left and in a shallow-bank high-illumination state (BR1, IRH), and as shown in Figure 3(D), when the saddle-type vehicle 100 is tilted to the left and in a shallow-bank low-illumination state (BR1, IRL), a high-beam light distribution pattern HP is formed in which the sixth high-beam portion HP6 at the right end has an 8th illuminance. The 8th illuminance is, for example, 15%. Also, as shown in Figure 3(B), when the saddle-type vehicle 100 is in a non-bank low-illumination state (<Thb1, IRL), a high-beam light distribution pattern HP is formed in which the sixth high-beam portion HP6 has an 9th illuminance. The 9th illuminance is, for example, 50%.

[0043] Furthermore, as shown in Figure 3(E), when the saddle-type vehicle 100 is tilted to the left and in a deep bank high-illumination state (BR2, IRH), and as shown in Figure 3(F), when the saddle-type vehicle 100 is tilted to the left and in a deep bank low-illumination state (BR2, IRL), a high-beam light distribution pattern HP is formed in which the sixth high-beam portion HP6 has a tenth illuminance that is lower than the eighth and ninth illuminances. The tenth illuminance is, for example, 10%.

[0044] (Control of the Light Distribution Pattern LP for Low Beam) When the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the high illuminance range IRH, the light distribution control device 4 controls the vehicle lamp 2 so that the bank angle is less than the first bank angle threshold value Thb1 and the illuminance of at least a part of the region on the side opposite to the side where the saddle-type vehicle 100 in the light distribution pattern LP for low beam tilts is lower than when the ambient illuminance is within the high illuminance range IRH. Further, when the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the low illuminance range IRL, the light distribution control device 4 controls the vehicle lamp 2 so that the illuminance of at least a part of the light distribution pattern LP for low beam is lower than when the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the high illuminance range IRH.

[0045] Further, when the bank angle is within the second bank angle range BR2 and the ambient illuminance is within the high illuminance range IRH, the light distribution control device 4 controls the vehicle lamp 2 so that the illuminance of at least a part of the light distribution pattern LP for low beam is lower than when the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the high illuminance range IRH. Further, when the bank angle is within the second bank angle range BR2 and the ambient illuminance is within the low illuminance range IRL, the light distribution control device 4 controls the vehicle lamp 2 so that the illuminance of at least a part of the light distribution pattern LP for low beam is lower than when the bank angle is within the first bank angle range BR1 and the ambient illuminance is within the low illuminance range IRL.

[0046] Further, when the bank angle is greater than or equal to the first bank angle threshold value Thb1, the light distribution control device 4 controls the vehicle lamp 2 so that the illuminance of at least a part of the region on the side where the saddle-type vehicle 100 in the light distribution pattern LP for low beam tilts is higher than when the bank angle is less than the first bank angle threshold value Thb1.

[0047] In this embodiment, as an example, when the saddle-riding type vehicle 100 is in a non-bank high illuminance state (<Thb1, IRH), as shown in FIG. 3(A), for example, a light distribution pattern LP for a low beam in which the fourth low beam portion LP4 at the right end has an eleventh illuminance is formed. The eleventh illuminance is, for example, 70%. Also, as shown in FIG. 3(C), when the saddle-riding type vehicle 100 is tilted to the left and in a shallow bank high illuminance state (BR1, IRH), a light distribution pattern LP for a low beam in which the fourth low beam portion LP4 has a twelfth illuminance lower than the eleventh illuminance is formed. The twelfth illuminance is, for example, 40%. Further, as shown in FIG. 3(D), when the saddle-riding type vehicle 100 is tilted to the left and in a shallow bank low illuminance state (BR1, IRL), a light distribution pattern LP for a low beam in which the fourth low beam portion LP4 has a thirteenth illuminance lower than the twelfth illuminance is formed. The thirteenth illuminance is, for example, 30%.

[0048] Also, as shown in FIG. 3(E), when the saddle-riding type vehicle 100 is tilted to the left and in a deep bank high illuminance state (BR2, IRH), a light distribution pattern LP for a low beam in which the fourth low beam portion LP4 has a fourteenth illuminance lower than the twelfth illuminance is formed. The fourteenth illuminance is, as an example, an illuminance of 25%. Also, as shown in FIG. 3(F), when the saddle-riding type vehicle 100 is tilted to the left and in a deep bank low illuminance state (BR2, IRL), a light distribution pattern LP for a low beam in which the fourth low beam portion LP4 has a fifteenth illuminance lower than the thirteenth illuminance is formed. The fifteenth illuminance is, as an example, an illuminance of 25%.

[0049] Also, as shown in FIG. 3(A), when the saddle-riding type vehicle 100 is in a non-bank high illuminance state (<Thb1, IRH), a light distribution pattern LP for a low beam in which the first low beam portion LP1 at the left end has a sixteenth illuminance is formed. The sixteenth illuminance is, for example, 70%. Also, as shown in FIG. 3(B), when the saddle-riding type vehicle 100 is in a non-bank low illuminance state (<Thb1, IRL), a light distribution pattern LP for a low beam in which the first low beam portion LP1 has a seventeenth illuminance is formed. The seventeenth illuminance is, for example, 40%.

[0050] Furthermore, as shown in Figure 3(C), when the saddle-type vehicle 100 is tilted to the left and in a shallow bank high-illumination state (BR1, IRH), as shown in Figure 3(D), when the saddle-type vehicle 100 is tilted to the left and in a shallow bank low-illumination state (BR1, IRL), as shown in Figure 3(E), when the saddle-type vehicle 100 is tilted to the left and in a deep bank high-illumination state (BR2, IRH), and as shown in Figure 3(F), when the saddle-type vehicle 100 is tilted to the left and in a deep bank low-illumination state (BR2, IRL), a low-beam light distribution pattern LP is formed in which the first low-beam portion LP1 has an 18th illuminance that is higher than the 16th and 17th illuminances. The 18th illuminance is, for example, 75%.

[0051] (Control of the light distribution pattern in the non-bank state) As shown in Figure 3(B), when the saddle-type vehicle 100 is in a non-bank low-illumination state (<Thb1, IRL), the light distribution control device 4 controls the vehicle lamp 2 to make the illuminance of at least a part of the high beam light distribution pattern HP higher than when the saddle-type vehicle 100 is in a non-bank high-illumination state (<Thb1, IRH), as shown in Figure 3(A). In this embodiment, the overall illuminance of the high beam light distribution pattern HP is higher when the ambient illuminance is low than when it is high, and the vehicle lamp 2 is controlled so that the illuminance of the central part is higher than the illuminance of the edges by a larger illuminance difference.

[0052] As an example, in a non-bank high-illumination state (<Thb1, IRH), a high-beam light distribution pattern HP is formed where the first high-beam section HP1 and the sixth high-beam section HP6 have an illuminance of 15%, the second high-beam section HP2 and the fifth high-beam section HP5 have an illuminance of 35%, and the third high-beam section HP3 and the fourth high-beam section HP4 have an illuminance of 40%. In a non-bank low-illumination state (<Thb1, IRL), a high-beam light distribution pattern HP is formed where the first high-beam section HP1 and the sixth high-beam section HP6 have an illuminance of 50%, the second high-beam section HP2 and the fifth high-beam section HP5 have an illuminance of 75%, and the third high-beam section HP3 and the fourth high-beam section HP4 have an illuminance of 85%.

[0053] Furthermore, when the saddle-type vehicle 100 is in a non-bank low-illumination state (<Thb1, IRL), the light distribution control device 4 controls the vehicle lamp 2 so that the illuminance of the central part of the low-beam light distribution pattern LP is higher than the illuminance of the edges by a larger illuminance difference than when the saddle-type vehicle 100 is in a non-bank high-illumination state (<Thb1, IRH). For example, the light distribution control device 4 may lower the illuminance of the first low-beam section LP1 and the fourth low-beam section LP4, or raise the illuminance of the second low-beam section LP2 and the third low-beam section LP3, or do both.

[0054] As an example, in a non-bank high-illumination state (<Thb1, IRH), a low-beam light distribution pattern LP is formed with 70% illuminance in the first low-beam section LP1 to the fourth low-beam section LP4. Conversely, in a non-bank low-illumination state (<Thb1, IRL), a low-beam light distribution pattern LP is formed with 40% illuminance in the first low-beam section LP1 and the fourth low-beam section LP4, and 70% illuminance in the second low-beam section LP2 and the third low-beam section LP3.

[0055] The first bank threshold Thb1, the second bank threshold Thb2, the first bank angle range BR1, the second bank angle range BR2, the illuminance threshold Thi, the high illuminance range IRH, and the low illuminance range IRL can be predetermined by the designer based on experiments and simulations. For example, the first bank threshold Thb1 is 5°, the second bank threshold Thb2 is 15°, and the illuminance threshold Thi is 3000 lux. Therefore, the first bank angle range BR1 is 5° or more and less than 15°, the second bank angle range BR2 is 15° or more, the high illuminance range IRH is 3000 lux or more, and the low illuminance range IRL is less than 3000 lux. Each threshold and range is predetermined and stored in the storage medium 10. In addition, the illuminance of each part in each light distribution pattern can be set appropriately based on experiments and simulations by the designer.

[0056] In this embodiment, the bank angle is divided into three stages, but the bank angle may be divided into two stages, or four or more stages. If the bank angle is divided into two stages, for example, the entire bank angle range above the first bank threshold Thb1 may be defined as the first bank angle range BR1. If the bank angle is divided into four or more stages, for example, at least one of the first bank angle range BR1 and the second bank angle range BR2 may be divided, or the second bank angle range BR2 may be defined as the range above the second bank threshold Thb2 and below the third bank threshold Thb3, with one or more bank angle ranges set above the second bank angle range BR2.

[0057] Furthermore, although the ambient illuminance is divided into two stages in this embodiment, the ambient illuminance may be divided into three or more stages. In this case, at least one of the high illuminance range IRH and the low illuminance range IRL may be divided, or, if the illuminance threshold Thi is defined as the first illuminance threshold Thi, the high illuminance range IRH may be defined as the range from the first illuminance threshold Thi1 to the second illuminance threshold Thi2, and one or more illuminance ranges may be set above the high illuminance range IRH.

[0058] Furthermore, this embodiment includes a computer program executed by the light distribution control device 4. This computer program causes the light distribution control device 4 to execute a function to control the vehicle lighting device 2 so as to change the light distribution pattern PTN according to the combination of the bank angle of the saddle-type vehicle 100 and the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle 100. This embodiment also includes a storage medium 10 on which the computer program is stored.

[0059] As described above, the light distribution control device 4 according to this embodiment controls the vehicle lamp 2 to change the light distribution pattern PTN according to the combination of the bank angle of the saddle-type vehicle 100 and the ambient illuminance. This allows for a more detailed breakdown of the driving state of the saddle-type vehicle 100 than when based on only one of the bank angle or ambient illuminance, and enables the light distribution pattern PTN to be dynamically changed according to each driving state. Therefore, the visibility of the driver of the saddle-type vehicle 100 can be further improved, and the glare experienced by the driver of the vehicle in front can be further suppressed. Thus, the safety of vehicle operation can be improved.

[0060] In this embodiment, the light distribution control device 4 increases the illuminance of at least a portion of the additional light distribution pattern on the tilted side of the saddle-type vehicle 100 when the saddle-type vehicle 100 is in a shallow bank high-illumination state compared to when it is in a non-banked state, and increases the illuminance of at least a portion of the additional light distribution pattern when the saddle-type vehicle 100 is in a shallow bank low-illumination state compared to when it is in a shallow bank high-illumination state. Furthermore, the light distribution control device 4 increases the illuminance of at least a portion of the additional light distribution pattern when the saddle-type vehicle 100 is in a deep bank high-illumination state compared to when it is in a shallow bank high-illumination state, and increases the illuminance of at least a portion of the additional light distribution pattern when the deep bank low-illumination state compared to when it is in a shallow bank low-illumination state.

[0061] In other words, when the saddle-type vehicle 100 tilts, the light distribution control device 4 increases the illuminance of the additional light distribution pattern that illuminates the path ahead of the saddle-type vehicle 100. In doing so, within the same bank angle range, the illuminance is increased more significantly when the ambient illuminance is low than when it is high. Also, within the same ambient illuminance range, the illuminance is increased more significantly when the bank angle is large than when it is small. This improves the visibility of the driver of the saddle-type vehicle 100 when banking.

[0062] Furthermore, when the saddle-type vehicle 100 is in a deep bank high-illumination state, the light distribution control device 4 increases the illuminance of at least a portion of the additional light distribution pattern on the side to which the saddle-type vehicle 100 is tilted, compared to when it is in a shallow bank low-illumination state. In other words, the light distribution control device 4 adjusts the illuminance of the additional light distribution pattern by prioritizing the bank angle over ambient illuminance. This can further improve the visibility of the driver of the saddle-type vehicle 100 when banking. Note that if the ambient illuminance is sufficiently high, the formation of the additional light distribution pattern when banking may be avoided.

[0063] Furthermore, when the saddle-type vehicle 100 is in a shallow bank high-illumination state, the light distribution control device 4 increases the illuminance of at least a portion of the area on the side of the tilted saddle-type vehicle 100 in the high-beam light distribution pattern HP compared to when it is in a non-bank high-illumination state, and when it is in a shallow bank low-illumination state, it increases the illuminance of at least a portion of the high-beam light distribution pattern HP compared to when it is in a shallow bank high-illumination state. In other words, when the saddle-type vehicle 100 is tilted, the light distribution control device 4 increases the illuminance of the portion of the high-beam light distribution pattern HP that illuminates the area ahead of the saddle-type vehicle 100. At that time, within the same bank angle range, the illuminance is increased more significantly when the ambient illuminance is low than when it is high. This improves the visibility of the driver of the saddle-type vehicle 100 when banking.

[0064] Furthermore, when the vehicle is in a deep bank state, the light distribution control device 4 reduces the illuminance of at least a portion of the area in the high beam light distribution pattern HP opposite to the side to which the saddle-type vehicle 100 is tilted, compared to when it is in a non-bank state or a shallow bank state. This suppresses glare received by the driver of the vehicle in front. It also makes it easier for the driver of the saddle-type vehicle 100 to direct their line of sight in the direction of travel of the saddle-type vehicle 100.

[0065] Furthermore, when the saddle-type vehicle 100 is in a shallow bank high-illumination state, the light distribution control device 4 reduces the illuminance of at least a portion of the area in the low beam light distribution pattern LP opposite to the side to which the saddle-type vehicle 100 is tilted, compared to when it is in a non-bank high-illumination state. When it is in a shallow bank low-illumination state, the light distribution control device 4 reduces the illuminance of at least a portion of the low beam light distribution pattern LP compared to when it is in a shallow bank high-illumination state. Furthermore, when the saddle-type vehicle 100 is in a deep bank high-illumination state, the light distribution control device 4 reduces the illuminance of at least a portion of the low beam light distribution pattern LP compared to when it is in a shallow bank high-illumination state. When it is in a deep bank low-illumination state, the light distribution control device 4 reduces the illuminance of at least a portion of the low beam light distribution pattern LP compared to when it is in a shallow bank low-illumination state.

[0066] In other words, when the saddle-type vehicle 100 is tilted, the light distribution control device 4 reduces the illuminance in the low beam light distribution pattern LP in areas where there is a high possibility of overlapping with the driver of the vehicle in front. At that time, within the first bank angle range BR1, the illuminance is reduced more significantly when the ambient illuminance is lower than when it is high. Also, within the same ambient illuminance range, the illuminance is reduced more significantly when the bank angle is larger than when it is small. This makes it possible to suppress the glare received by the driver of the vehicle in front. It also makes it easier for the driver of the saddle-type vehicle 100 to direct their line of sight in the direction of travel of the saddle-type vehicle 100.

[0067] Furthermore, in situations where the ambient illumination around the saddle-type vehicle 100 is low, the importance of guiding the driver's gaze tends to be higher than in situations where the ambient illumination is high. To address this, within the first bank angle range BR1, by making the illumination in the low-illumination range IRL lower than the high-illumination range IRH in the low-illumination range LP of the low-beam light distribution pattern LP, the contrast between the area the driver should look at and other areas is more emphasized, enabling more effective gaze guidance. In addition, it is possible to mitigate the increase in power consumption caused by increasing the illumination of the additional light distribution pattern and the high-beam light distribution pattern HP when the ambient illumination is low compared to when the ambient illumination is high.

[0068] Within the second bank angle range BR2, the illuminance of the area on the opposite side of the tilted side of the saddle-type vehicle 100 in the low beam light distribution pattern LP, for example, the fourth low beam portion LP4, is the same in both the high-illuminance range IRH and the low-illuminance range IRL. The reason why the illuminance of the fourth low beam portion LP4 is not reduced in the low-illuminance range IRL compared to the high-illuminance range IRH is that the reduction in illuminance of the fourth low beam portion LP4 in the high-illuminance range IRH creates a sufficient illuminance difference between the fourth low beam portion LP4 and other parts. This is also to ensure minimum visibility of the forward area illuminated by the fourth low beam portion LP4. Of course, even within the second bank angle range BR2, the illuminance of the area on the opposite side of the tilted side of the saddle-type vehicle 100 in the low beam light distribution pattern LP may be lower in the low-illuminance range IRL than in the high-illuminance range IRH.

[0069] Furthermore, when the saddle-type vehicle 100 is banked, the light distribution control device 4 increases the illuminance of at least a portion of the area on the side of the low-beam light distribution pattern LP that the saddle-type vehicle 100 is tilted to, compared to when it is not banked. In other words, when the saddle-type vehicle 100 is tilted, the light distribution control device 4 increases the illuminance of the portion of the low-beam light distribution pattern LP that illuminates the area ahead of the saddle-type vehicle 100. This improves the visibility of the driver of the saddle-type vehicle 100 when banking.

[0070] Furthermore, when the saddle-type vehicle 100 is in a non-bank low-illumination state, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of at least a portion of the high-beam light distribution pattern HP compared to when it is in a non-bank high-illumination state. This further improves the visibility of the driver of the saddle-type vehicle 100. Also, when the saddle-type vehicle 100 is in a non-bank low-illumination state, the light distribution control device 4 controls the vehicle lamp 2 to increase the illuminance of the central part of the low-beam light distribution pattern LP to be higher than the illuminance of the edges by a larger illuminance difference compared to when it is in a non-bank high-illumination state. This helps to guide the driver's gaze of the saddle-type vehicle 100 and reduces the power consumed by the vehicle lamp 2.

[0071] The embodiments of the present invention have been described in detail above. The embodiments described above are merely examples of how to implement the present invention. The content of the embodiments does not limit the technical scope of the present invention, and many design changes, such as changes, additions, and deletions of components, are possible as long as they do not depart from the spirit of the invention as defined in the claims. New embodiments with design changes will have the effects of both the combined embodiments and the variations. In the embodiments described above, the content in which such design changes are possible is emphasized with notations such as "in this embodiment" or "in this embodiment," but design changes are also permitted even if there are no such notations. Any combination of the above components is also valid as an embodiment of the present invention. The hatching applied to the cross-section in the drawings does not limit the material of the object to which the hatching is applied.

[0072] The invention relating to the above-described embodiment may be specified by the following items: [Item 1] A light distribution control device (4) that controls the formation of a light distribution pattern (PTN) by a vehicle light fixture (2) mounted on a saddle-type vehicle (100), the light distribution control device (4) that controls the vehicle light fixture (2) to change the light distribution pattern (PTN) according to a combination of the bank angle of the saddle-type vehicle (100) and the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle (100). [Item 2] The vehicle lamp (2) is capable of forming a left additional light distribution pattern (LAP) formed in a region including the area above the left end of the high beam light distribution pattern (HP), and a right additional light distribution pattern (RAP) formed in a region including the area above the right end of the high beam light distribution pattern (HP), and the light distribution control device (4) controls the vehicle lamp (2) to increase the illuminance of at least a portion of the additional light distribution patterns (LAP, RAP) on the side on which the saddle-type vehicle (100) is tilted, when the bank angle is within a predetermined first bank angle range (BR1) that is greater than or equal to a predetermined first bank threshold (Thb1), and the ambient illuminance is greater than or equal to a predetermined illuminance threshold (Thi), compared to when the bank angle is less than the first bank threshold (Thb1). The first item describes a light distribution control device (4) that controls the vehicle lighting fixture (2) to make at least a portion of the illuminance higher than when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is less than the illuminance threshold (Th) when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is equal to or greater than the illuminance threshold (Th). [Item 3] The light distribution control device (4) controls the vehicle lighting fixture (2) to make at least a portion of the illuminance higher than when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is above the illuminance threshold (Th) when the bank angle is within the second bank angle range (BR2) and the ambient illuminance is below the illuminance threshold (Th) when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is below the illuminance threshold (Th) when the bank angle is within the second bank angle range (BR2) and the ambient illuminance is below the illuminance threshold (Th) as described in Item 2.[Item 4] The light distribution control device (4) controls the vehicle lighting fixture (2) to make at least a portion of the illuminance higher than when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is below the illuminance threshold (Th) when the bank angle is within the second bank angle range (BR2) and the ambient illuminance is above the illuminance threshold (Th), as described in Item 3. [Item 5] The vehicle lamp (2) is capable of forming a high beam light distribution pattern (HP), and the light distribution control device (4) controls the vehicle lamp (2) to increase the illuminance in at least a portion (HP1 to HP6) of the area on the side where the saddle-type vehicle (100) is tilted in the high beam light distribution pattern (HP) when the bank angle is within a predetermined first bank angle range (BR1) which is equal to or greater than a predetermined first bank threshold (Thb1) and the ambient illuminance is equal to or greater than a predetermined illuminance threshold (Thi), compared to when the bank angle is less than the first bank threshold (Thb1) and the ambient illuminance is equal to or greater than the illuminance threshold (Thi). A light distribution control device (4) according to any of the first to fourth items, wherein when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is less than the illuminance threshold (Th), the vehicle lighting fixture (2) controls the vehicle lighting fixture (2) to make the illuminance of at least a portion (HP1 to HP6) of the high beam light distribution pattern (HP) higher than when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is greater than or equal to the illuminance threshold (Th). [Item 6] A light distribution control device (4) according to the fifth item, wherein when the bank angle is within a predetermined second bank angle range (BR2) which is greater than the first bank angle range (BR1), the vehicle lighting fixture (2) controls the vehicle lighting fixture (2) to make the illuminance of at least a portion (HP1 to HP6) of the high beam light distribution pattern (HP) on the side opposite to the side on which the saddle-type vehicle (100) is tilted lower than when the bank angle is less than the second bank angle range (BR2).[Item 7] The vehicle lamp (2) is capable of forming a low beam light distribution pattern (LP), and the light distribution control device (4) controls the vehicle lamp (2) to lower the illuminance in at least a portion (LP1 to LP4) of the area on the opposite side of the tilted side of the saddle-type vehicle (100) in the low beam light distribution pattern (LP) compared to when the bank angle is within a predetermined first bank angle range (BR1) of a predetermined first bank threshold (Thb1) or greater and the ambient illuminance is above a predetermined illuminance threshold (Thi), compared to when the bank angle is below the first bank threshold (Thb1) and the ambient illuminance is above the illuminance threshold (Thi). A light distribution control device (4) according to any of the first to sixth items, which controls a vehicle lamp (2) to lower the illuminance of at least a portion (LP1 to LP4) of the low beam light distribution pattern (HP) to a lower level than when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is less than the illuminance threshold (Th) when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is equal to or greater than the illuminance threshold (Th). [Item 8] The light distribution control device (4) controls the vehicle lamp (2) to lower the illuminance of at least a portion (LP1 to LP4) of the low beam light distribution pattern (LP) than when the bank angle is within a predetermined second bank angle range (BR2) which is greater than the first bank angle range (BR1) and the ambient illuminance is above the illuminance threshold (Thi), and controls the vehicle lamp (2) to lower the illuminance of at least a portion (LP1 to LP4) of the low beam light distribution pattern (LP) than when the bank angle is within the first bank angle range (BR1) and the ambient illuminance is above the illuminance threshold (Thi), as described in Item 7.[Item 9] The light distribution control device (4) controls the vehicle lamp (2) so that when the bank angle is greater than or equal to the first bank threshold (Thb1), the illuminance in at least a portion (LP1 to LP4) of the area on the side where the saddle-type vehicle (100) is tilted in the low beam light distribution pattern (LP) is higher than when the bank angle is less than the first bank threshold (Thb1), the light distribution control device (4) according to Item 7 or Item 8. [Item 10] A vehicle lamp system (1) comprising a vehicle lamp (2) mounted on a saddle-type vehicle (100), an attitude sensor (6) for detecting the bank angle of the saddle-type vehicle (100), an illuminance sensor (18) for detecting the illuminance of the surrounding environment of the saddle-type vehicle (100), and a light distribution control device (4) according to any one of Items 1 to 9. [Item 11] A computer program executed by a light distribution control device (4) that controls the formation of a light distribution pattern (PTN) by a vehicle light fixture (2) mounted on a saddle-type vehicle (100), the computer program causing the light distribution control device (4) to execute a function to control the vehicle light fixture (2) so as to change the light distribution pattern (PTN) according to a combination of the bank angle of the saddle-type vehicle (100) and the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle (100). [Item 12] A light distribution control method that controls the formation of a light distribution pattern (PTN) by a vehicle light fixture (2) mounted on a saddle-type vehicle (100), the light distribution control method including controlling the vehicle light fixture (2) so as to change the light distribution pattern (PTN) according to a combination of the bank angle of the saddle-type vehicle (100) and the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle (100).

[0073] This invention can be used in light distribution control devices, vehicle lighting systems, and computer programs.

[0074] 1. Vehicle lighting system, 2. Vehicle lighting fixture, 4. Light distribution control device, 100. Saddle-type vehicle, BR1 First bank angle range, BR2 Second bank angle range, HP High beam light distribution pattern, LP Low beam light distribution pattern, LAP Left additional light distribution pattern, PTN Light distribution pattern, RAP Right additional light distribution pattern, Thb1 First bank threshold, Thi Illuminance threshold.

Claims

1. A light distribution control device for controlling the formation of a light distribution pattern by a vehicle light fixture mounted on a saddle-type vehicle, the light distribution control device for controlling the vehicle light fixture to change the light distribution pattern according to a combination of the bank angle of the saddle-type vehicle and the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle.

2. The vehicle lamp is capable of forming a left additional light distribution pattern formed in a region including the area above the left end of the high beam light distribution pattern, and a right additional light distribution pattern formed in a region including the area above the right end of the high beam light distribution pattern, wherein the light distribution control device controls the vehicle lamp to make the illuminance of at least a portion of the additional light distribution pattern on the tilted side of the saddle-type vehicle higher than when the bank angle is less than the first bank threshold when the bank angle is within a predetermined first bank angle range of a predetermined first bank threshold and the ambient illuminance is above a predetermined illuminance threshold, and controls the vehicle lamp to make the illuminance of at least a portion higher than when the bank angle is within the first bank angle range and the ambient illuminance is above the illuminance threshold when the bank angle is within the first bank angle range and the ambient illuminance is above the illuminance threshold, according to claim 1.

3. The light distribution control device according to claim 2, wherein when the bank angle is within a predetermined second bank angle range greater than the first bank angle range and the ambient illuminance is greater than or equal to the illuminance threshold, the vehicle lamp is controlled to make at least a portion of the illuminance higher than when the bank angle is within the first bank angle range and the ambient illuminance is greater than or equal to the illuminance threshold; and when the bank angle is within the second bank angle range and the ambient illuminance is less than the illuminance threshold, the vehicle lamp is controlled to make at least a portion of the illuminance higher than when the bank angle is within the first bank angle range and the ambient illuminance is less than the illuminance threshold.

4. The light distribution control device according to claim 3, wherein when the bank angle is within the second bank angle range and the ambient illuminance is above the illuminance threshold, the light distribution control device controls the vehicle lighting fixture to make at least a portion of the illuminance higher than when the bank angle is within the first bank angle range and the ambient illuminance is below the illuminance threshold.

5. The vehicle lamp is capable of forming a high beam light distribution pattern, and the light distribution control device controls the vehicle lamp to increase the illuminance of at least a portion of the region on the side of the saddle-type vehicle that is tilted in the high beam light distribution pattern compared to when the bank angle is less than the first bank threshold and the ambient illuminance is greater than or equal to the illuminance threshold, when the bank angle is within the first bank angle range and the ambient illuminance is less than the illuminance threshold, and controls the vehicle lamp to increase the illuminance of at least a portion of the high beam light distribution pattern compared to when the bank angle is within the first bank angle range and the ambient illuminance is greater than or equal to the illuminance threshold. The light distribution control device according to any one of claims 1 to 4.

6. The light distribution control device according to claim 5, wherein when the bank angle is within a predetermined second bank angle range greater than the first bank angle range, the vehicle lamp is controlled to reduce the illuminance of at least a portion of the area on the side opposite to the side on which the saddle-type vehicle is tilted in the high beam light distribution pattern compared to when the bank angle is less than the second bank angle range.

7. The vehicle lamp is capable of forming a low beam light distribution pattern, and the light distribution control device controls the vehicle lamp to lower the illuminance of at least a portion of the region on the side opposite to the side on which the saddle-type vehicle is tilted, when the bank angle is within a predetermined first bank angle range of a predetermined first bank threshold and the ambient illuminance is above a predetermined illuminance threshold, compared to when the bank angle is below the first bank threshold and the ambient illuminance is above the illuminance threshold, and controls the vehicle lamp to lower the illuminance of at least a portion of the low beam light distribution pattern, compared to when the bank angle is within the first bank angle range and the ambient illuminance is above the illuminance threshold. The light distribution control device according to any one of claims 1 to 4.

8. The light distribution control device according to claim 7, wherein when the bank angle is within a predetermined second bank angle range greater than the first bank angle range and the ambient illuminance is greater than or equal to the illuminance threshold, the vehicle lamp is controlled to lower the illuminance of at least a portion of the low beam light distribution pattern than when the bank angle is within the first bank angle range and the ambient illuminance is greater than or equal to the illuminance threshold, and when the bank angle is within the second bank angle range and the ambient illuminance is less than the illuminance threshold, the vehicle lamp is controlled to lower the illuminance of at least a portion of the low beam light distribution pattern than when the bank angle is within the first bank angle range and the ambient illuminance is less than the illuminance threshold.

9. The light distribution control device according to claim 7, wherein when the bank angle is greater than or equal to the first bank threshold, the vehicle lamp is controlled to increase the illuminance of at least a portion of the region on the side of the saddle-type vehicle that is tilted in the low beam light distribution pattern compared to when the bank angle is less than the first bank threshold.

10. A vehicle lighting system comprising: a vehicle lighting device mounted on a saddle-type vehicle; an attitude sensor for detecting the bank angle of the saddle-type vehicle; an illuminance sensor for detecting the illuminance of the surrounding environment of the saddle-type vehicle; and a light distribution control device according to any one of claims 1 to 4.

11. A computer program executed by a light distribution control device that controls the formation of a light distribution pattern by a vehicle light fixture mounted on a saddle-type vehicle, the computer program causing the light distribution control device to execute a function to control the vehicle light fixture so as to change the light distribution pattern according to a combination of the bank angle of the saddle-type vehicle and the ambient illuminance, which is the illuminance of the environment surrounding the saddle-type vehicle.

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