JP7492965B2 - Vehicle lighting fixtures - Google Patents

Description

The present invention relates to a vehicle lamp for use in an automobile or the like.

Vehicle lamps are generally capable of switching between low beam and high beam. Low beam is used to illuminate the vicinity of the vehicle with a predetermined illuminance, and light distribution regulations are established so as not to cause glare to oncoming vehicles or preceding vehicles, and is mainly used when driving in urban areas. On the other hand, high beam is used to illuminate a wide range and distant area ahead with a relatively high illuminance, and is mainly used when driving at high speed on roads with few oncoming vehicles or preceding vehicles. Therefore, high beam has better visibility for the driver than low beam, but has a problem of causing glare to drivers of vehicles and pedestrians in front of the vehicle.

In recent years, ADB (Adaptive Driving Beam) technology has been proposed, which dynamically and adaptively controls the high beam light distribution pattern based on the conditions around the vehicle. The ADB technology detects the presence or absence of a preceding vehicle, an oncoming vehicle, or a pedestrian ahead of the vehicle, and reduces the glare given to the vehicle or pedestrian by dimming the area corresponding to the vehicle or pedestrian.

As a method for realizing the ADB function, a shutter method for controlling an actuator, a rotary method, an LED array method, and the like have been proposed. The shutter method and the rotary method are capable of continuously changing the width of the light-shielding area, but the number of light-shielding areas is limited to one. The LED array method is capable of setting multiple light-shielding areas, but the width of the light-shielding area is limited by the irradiation width of the LED chip, so it is discrete.

The present applicant has proposed a blade scan method as an ADB method capable of solving these problems (see Patent Documents 1 and 2). The blade scan method forms a desired light distribution pattern in front of the vehicle by irradiating light onto a rotating reflector (blade), reflecting the incident light at an angle according to the rotational position of the reflector, and scanning the reflected light in front of the vehicle while changing the on/off or light amount of the light source according to the rotational position of the reflector.

JP 2019-006192 A International Publication No. 2016/104319

The vehicle lamp disclosed in Patent Document 1 includes a plurality of light-emitting units that can be individually controlled to be turned on and off. The light (beam) emitted from the plurality of light-emitting units is reflected by a reflector that moves at high speed and is scanned in the horizontal direction in front of the vehicle. The light distribution pattern is a superposition of the beams from the plurality of light-emitting units.

1(a) and (b) are diagrams for explaining the formation of a light distribution pattern by a plurality of light-emitting units. Here, for the sake of simplicity, a five-channel light-emitting unit is considered. For example, the high beam needs to irradiate a range of 25° to the left and right, respectively, centered on the straight-ahead direction of the vehicle, and therefore a total of about 50°. As shown in FIG. 1(a), the five-channel light-emitting unit covers different irradiation areas A ₁ to A ₅ shifted in the horizontal direction. The beam of the light-emitting unit of each channel instantaneously irradiates a certain spot (also called an instantaneous irradiation spot) SP. This irradiation spot SP is scanned in the horizontal direction, and the irradiation area of each channel is irradiated. The light distribution pattern formed by this vehicle lamp is a superposition of the irradiation areas A ₁ to A ₅ of the five channels, as shown in FIG. 1(b).

Patent Document 1 discloses a lamp capable of switching between multiple light distribution modes such as normal mode, motorway mode, and town mode. A different basic light distribution pattern is defined for each light distribution mode, and the basic light distribution pattern is defined by a combination of on and off of light-emitting units of multiple channels. The vehicle lamp selects a light distribution mode according to a driving scene and forms a basic light distribution pattern that is optimal for the driving scene. Then, when an oncoming vehicle or a preceding vehicle is detected, the range where the oncoming vehicle or preceding vehicle exists is partially blocked based on the basic light distribution pattern.

When the basic light distribution pattern is switched, the illumination area of each channel is turned on or off. If the illumination areas of each channel are turned on or off separately, the driver (user) feels uncomfortable.

The present invention has been made in light of the above-mentioned circumstances, and an exemplary purpose of an embodiment of the present invention is to provide a vehicle lamp that reduces the sense of discomfort felt when switching an illuminated area on and off.

A vehicle lamp according to an embodiment of the present invention includes a variable light distribution lamp and a controller. The variable light distribution lamp includes a plurality of light-emitting units that can be individually switched on and off, and a scanning optical system that scans the beams of the plurality of light-emitting units to illuminate a plurality of illumination areas corresponding to the plurality of light-emitting units. The controller controls the variable light distribution lamp to switch the plurality of illumination areas on and off. When switching a certain illumination area from on to off, the controller (i) moves the right and left ends of the illumination area toward the reference position if the illumination area to be switched straddles a reference position.

Another aspect of the present invention is also a vehicle lamp. The vehicle lamp includes a variable light distribution lamp and a controller. The variable light distribution lamp includes a plurality of light-emitting units that can be individually switched on and off, and a scanning optical system that scans the beams of the respective light-emitting units to illuminate a plurality of illumination areas corresponding to the plurality of light-emitting units. The controller controls the variable light distribution lamp to switch the illumination areas on and off. When switching a certain illumination area from off to on, the controller (iv) widens the illumination area from the reference position over time if the illumination area to be switched straddles a reference position.

According to an embodiment of the present invention, it is possible to reduce the sense of discomfort felt when switching an illumination area on and off.

1A and 1B are diagrams illustrating the formation of a light distribution pattern by a plurality of light-emitting units. 1 is a block diagram of a lighting system including a vehicle lamp according to an embodiment. 3A and 3B are diagrams for explaining the control of turning off the illumination areas that straddle the reference position. 4A and 4B are diagrams illustrating the extinguishing control of the illumination area located to the left of the reference position. 5A and 5B are diagrams illustrating the extinguishing control of the illumination area located to the left of the reference position. 11A and 11B are diagrams illustrating lighting control of an illumination area that crosses a reference position. 13A and 13B are diagrams illustrating lighting control of an illumination area located to the left of a reference position. 13A and 13B are diagrams illustrating lighting control of an illumination area located to the right of the reference position. FIG. 9A is a diagram showing changes in two illumination areas in the embodiment, and FIG. 9B is a diagram showing changes in two illumination areas in the comparative technology. 1 is a perspective view of a vehicle lamp according to an embodiment; FIG. 11A is a diagram showing an example of the layout of a plurality of light-emitting units, and FIG. 11B is a diagram showing the horizontal range of the illumination area covered by the plurality of light-emitting units. FIG. 2 is a circuit diagram showing a configuration example of a vehicle lamp. FIG. 13 is a diagram for explaining the operation of the lighting circuit of FIG. 12 .

(Overview of the embodiment)
An embodiment disclosed in this specification relates to a vehicle lamp. The vehicle lamp includes a variable light distribution lamp and a controller. The variable light distribution lamp includes a plurality of light-emitting units that can be individually switched on and off, and a scanning optical system that scans the beams of the plurality of light-emitting units and illuminates a plurality of illumination areas corresponding to the plurality of light-emitting units. The controller controls the variable light distribution lamp to switch the plurality of illumination areas on and off. When switching a certain illumination area from on to off, the controller (i) moves the right and left ends of the illumination area toward the reference position if the illumination area to be switched straddles a reference position.

According to this embodiment, the illuminated area is gradually turned off toward the reference position, which creates a sense of overall uniformity and reduces the sense of discomfort.

Furthermore, the controller (ii) moves the left end of the target projection area toward the right end when the target projection area is located to the left of the reference position, and (iii) moves the right end of the target projection area toward the left end when the target projection area is located to the right of the reference position. This creates a more uniform overall look and reduces discomfort.

When two or more illumination areas are switched from on to off, the transition times of the two or more illumination areas to be switched may be equal, so that the transition to off is completed at the same time, further enhancing the sense of unity.

The controller may be provided with a plurality of basic light distribution patterns each having a different combination of on/off states of a plurality of illumination areas, and the controls (i) to (iii) may be applied when switching between the basic light distribution patterns.

The controls (i)-(iii) may be applied to an illuminated area that is switched from on to off with an electronic swivel.

In one embodiment, when switching an illumination area from off to on, (iv) if the illumination area to be switched crosses a reference position, the controller expands the illumination area over time starting from the reference position.

According to this embodiment, the illumination area gradually lights up with the reference position as the center, which creates a sense of overall unity and reduces the sense of incongruity.

The controller (v) expands the illumination area over time starting from the right edge if the illumination area to be switched is located to the left of the reference position, and (vi) expands the illumination area over time starting from the left edge if the illumination area to be switched is located to the right of the reference position. This further enhances the sense of unity and reduces the sense of incongruity.

When two or more illumination areas are switched from off to on, the transition times of the two or more illumination areas to be switched may be equal. This allows the lighting transition to be completed simultaneously, further enhancing the sense of unity.

A plurality of basic light distribution patterns having different combinations of on/off of a plurality of irradiation areas may be defined in the controller, and the controls (iv) to (vi) may be applied when switching the basic light distribution patterns.

The controls (iv)-(vi) may be applied to an illumination area that is switched from off to on with electronic swivel.

The reference position may be the horizontal center of all the illumination areas. The horizontal center of all the illumination areas corresponds to the direction of travel of the vehicle, and can be said to be the direction that the driver looks most closely at. By switching on and off the multiple illumination areas based on this direction, the sense of discomfort can be further reduced.

(Embodiment)
The present invention will be described below with reference to the drawings based on preferred embodiments. The same or equivalent components, parts, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected to each other, but also a case in which component A and component B are indirectly connected to each other via other components that do not substantially affect the electrical connection state between them or that do not impair the function or effect achieved by the connection between them.

Similarly, "a state in which component C is provided between components A and B" includes not only a case in which components A and C, or components B and C, are directly connected to each other, but also a case in which they are indirectly connected to each other via other components that do not substantially affect the electrical connection state between them or that do not impair the functions or effects achieved by their combination.

2 is a block diagram of a lighting system 2 including a vehicle lamp 100 according to an embodiment. The vehicle lamp 100 receives control data instructing a light distribution pattern from an ADB ECU (Electronic Control Unit) 4, and forms a light distribution pattern in front of the vehicle according to the control data. The ADB ECU 4 may be built into the vehicle lamp 1.

The vehicle lamp 100 includes a low beam unit 102 and a high beam unit 104. The low beam unit 102 has a fixed light distribution pattern, and illuminates a predetermined area 702 on a virtual vertical screen 700.

The high beam unit 104 is an ADB (Adaptive Driving Beam) and is configured to be able to adaptively control the light distribution pattern 704 in accordance with the situation ahead of the vehicle and the state of the host vehicle. The high beam unit 104 includes a variable light distribution lamp 110 and a controller 120.

The variable light distribution lamp 110 is configured to have a variable light distribution. The variable light distribution lamp 110 includes a plurality of (N channels) light emitting units 112_1 to 112_N, a driver circuit 114, and a scanning optical system .

The light-emitting units 112_1 to 112_N can be individually switched on and off. The scanning optical system 130 horizontally scans the beams BM ₁ to BM _N of the light-emitting units 112_1 to 112_N, respectively, and irradiates the illumination areas A ₁ to A _N. A variable light distribution pattern 704 of high beam is formed by combining the illumination areas A ₁ to A _N. For example, the scanning frequency is 100 to 200 Hz, and the scanning period is 10 to 5 ms.

The driver circuit 114 controls the drive current flowing through the plurality of light-emitting units 112_1 to 112_N, and controls the on/off and light intensity of each light-emitting unit.

The vehicle lamp 100 is configured to be able to switch between a plurality of light distribution modes. The types of light distribution modes are not limited, but examples include normal mode, town mode, motorway mode, and rain mode. A plurality of basic light distribution patterns are defined corresponding to the plurality of light distribution modes. The basic light distribution patterns are defined by a combination of on/off of the plurality of illumination areas A ₁ to A _N and the brightness of the plurality of illumination areas A ₁ to A _N.

For example, in normal mode, all illumination areas A ₁ to A _N are on. In town mode, some of the illumination areas A ₁ to A _N are turned off to reduce the illuminance. In motorway mode, all illumination areas A ₁ to A _N are on, and the illuminance of the illumination areas A ₁ to A _N is set higher than in normal mode to illuminate a longer distance.

The controller 120 receives control data S1 instructing a light distribution pattern from the ADB ECU 4. Based on the control data S1, the controller 120 controls the variable light distribution lamp 110 so that the instructed light distribution pattern is formed in front of the vehicle. The format and signal form of the control data S1 are not particularly limited.

The control data S1 transmitted from the ADB ECU 4 to the controller 120 includes mode designation data S11 that designates a light distribution mode, i.e., a basic light distribution pattern. The controller 120 controls the variable light distribution lamp 110 so as to obtain the basic light distribution pattern designated by the mode designation data S11. Specifically, the controller 120 defines a set of setting values for on/off and drive current for the multiple light-emitting units 112_1 to 112_N for each basic light distribution pattern. The controller 120 controls the driver circuit 114 based on the set of setting values according to the mode designation data S11.

Furthermore, when an oncoming vehicle or a preceding vehicle is detected ahead of the vehicle, the ADB ECU 4 generates shading data S12 indicating the range in which the oncoming vehicle or the preceding vehicle exists, in other words, the range to be shaded, and supplies the data to the controller 120. The controller 120 controls the variable light distribution lamp 110 so as not to illuminate the shading range designated by the shading data S12 in the basic light distribution pattern.

When the basic light distribution pattern is switched, the multiple illumination areas A ₁ to A _N are switched on and off. If the basic light distribution pattern is changed instantly and discontinuously, the area that was illuminated with light up until that point may suddenly become dark or the illuminated area may suddenly move, which may cause discomfort to the driver or interfere with driving.

Therefore, when a change in the basic light distribution pattern is instructed, the controller 120 gradually changes the light distribution pattern over time toward the changed basic light distribution pattern. For example, the basic light distribution pattern is switched over in a transition time τ of about 500 ms to 2 seconds.

The on/off switching of the projection area is performed in different ways depending on the position of the projection area. In relation to the on/off switching, a reference position REF is defined in the horizontal direction on the virtual vertical screen 700. For example, this reference position REF is set to the vertical line (V line) of the virtual vertical screen 700, i.e., the 0° direction.

First, the control of turning off the irradiation area will be described. Figures 3(a) and (b) are diagrams for explaining the control of turning off the irradiation area _Ai that straddles the reference position REF. The positions of the left end E _L and the right end E _R of the irradiation area Ai are expressed as θ _L and θ _R in the angular coordinate system. In the example of Figure 3(a), since θ _L < 0°, 0° < θ _R hold, it can be said that the irradiation area _Ai straddles the reference position REF (0°). In this case, the controller 120 moves the left end E _L and the right end E _R of the irradiation area _Ai toward the reference position (θ = 0°) over the transition time τ. As a result, the width of the irradiation area _Ai narrows over time, and the irradiation area _Ai eventually disappears and turns off.

Fig. 3(b) is a diagram showing the change in the illumination area A _i in Fig. 3(a). The horizontal axis indicates the edge position (angle coordinate system), and the vertical axis indicates time. At time _t0 , an instruction to turn off the illumination area A _i is generated. The left end E _L moves rightward toward the reference position θ at a speed θ _L /τ. The right end E _R moves leftward toward the reference position θ at a speed θ _R /τ. At time _t1 , after the transition time τ has elapsed from time _t0 , the left end E _L and the right end E _R simultaneously reach the reference position REF, completing the turning off of the illumination area A _i .

4(a) and (b) are diagrams for explaining the control of turning off the illumination area A _i located to the left of the reference position REF. In the example of FIG. 4(a), θ _L <0°, θ _R <0° are satisfied, so it can be said that the illumination area A _i is located to the left of the reference position REF (0°). In this case, the controller 120 fixes the right end E _R of the illumination area A _i and moves the left end E _L toward the right end E _R over the transition time τ. This narrows the width of the illumination area A _i over time, and eventually the illumination area A _i disappears and turns off.

Fig. 4(b) is a diagram showing the change of the illumination area A _i in Fig. 4(a). At time _t0, an instruction to turn off the illumination area A _i is generated. The left end E _L moves rightward toward the right end E _R at a speed of (θ _R - _{θ L} )/τ. At time _t1 , after the transition time τ has elapsed from time _t0 , the left end E _L reaches the right end E _R , and turning off the illumination area A _i is completed.

5(a) and (b) are diagrams for explaining the control of turning off the illumination area A _i located to the left of the reference position REF. In the example of FIG. 5(a), θ _L >0°, θ _R >0° are satisfied, so it can be said that the illumination area A _i is located to the left of the reference position REF (0°). In this case, the controller 120 fixes the left end E _L of the illumination area A _i and moves the right end E _R toward the left end E _L over the transition time τ. This narrows the width of the illumination area A _i over time, and eventually the illumination area A _i disappears and turns off.

Fig. 5(b) is a diagram showing the change in the illumination area A _i in Fig. 5(a). At time _t0, an instruction to turn off the illumination area A _i is generated. The right end E _R moves leftward toward the left end E _L at a speed of (θ _R - _{θ L} )/τ. At time _t1 , after the transition time τ has elapsed from time _t0 , the right end E _R reaches the left end E _L , and turning off the illumination area A _i is completed.

Next, the lighting control of the irradiation area will be described. FIG. 6 is a diagram for explaining the lighting control of the irradiation area A _i that straddles the reference position REF. The controller 120 expands the irradiation area A _i over time, starting from the reference position REF. The horizontal axis indicates the edge position (angle coordinate system), and the vertical axis indicates time. When an instruction to turn on the irradiation area A _i is generated at time t ₀ , the controller 120 sets the left end E _L and the right end E _R of the irradiation area A _i to the reference position REF (0°). The left end E _L moves leftward toward the target position θ _L at a speed θ _L /τ, and the right end E _R moves rightward toward the target position θ _R at a speed θ _R /τ. At time t ₁ after the transition time τ has elapsed from time t ₀ , the left end E _L and the right end E _R simultaneously reach the target positions θ _L and θ _R , and the turning on of the irradiation area A _i is completed. The lighting control in FIG. 6 can be said to be the exact opposite process to the lighting control in FIG.

FIG. 7 is a diagram for explaining the lighting control of the irradiation area A _i located to the left of the reference position REF. When the irradiation area A _i is located to the left of the reference position REF, the controller 120 expands the irradiation area A _i over time, starting from the right end E _R. When an instruction to turn on the irradiation area A _i is generated at time t ₀ , the controller 120 sets the left end E _L and the right end E _R of the irradiation area A _i to the target position θ _R of the right end E _R. Then, the right end E _R is fixed, and the left end E _L is moved leftward toward the target position θ _L at a speed (θ _R - _{θ L} )/τ. At time t ₁ after the transition time τ has elapsed from time t ₀ , the left end E _L reaches the target position θ _L , and the turning on of the irradiation area A _i is completed. The lighting control in FIG. 7 can be said to be the exact opposite process to the turning off control in FIG. 4(b).

FIG. 8 is a diagram for explaining the lighting control of the irradiation area A _i located to the right of the reference position REF. When the irradiation area A _i is located to the right of the reference position REF, the controller 120 expands the irradiation area A _i over time, starting from the left end E _L. When an instruction to turn on the irradiation area A _i is generated at time t ₀ , the controller 120 sets the left end E _L and the right end E _R of the irradiation area A _i to the target position θ _L of the left end E _R. Then, the left end E _L is fixed, and the right end E _R is moved rightward toward the target position θ _R at a speed (θ _R - _{θ L} )/τ. At time t ₁ after the transition time τ has elapsed from time t ₀ , the right end E _R reaches the target position θ _R , and the turning on of the irradiation area A _i is completed. The lighting control of FIG. 8 can be said to be the exact opposite process to the turning off control of FIG. 5(b).

The above is the operation of the vehicular lamp 100. According to this vehicular lamp 100, when some illumination areas are turned off, the illumination areas are gradually turned off toward the reference position regardless of the position of each illumination area, so that an overall sense of unity is created and a sense of incongruity can be reduced.

This advantage is remarkable when two or more illumination areas are turned off at the same time. As an example, consider the case where two illumination areas straddling a reference position are turned off at the same time. FIG. 9(a) is a diagram showing the change of two illumination areas A _i , A _j in the embodiment, and FIG. 9(b) is a diagram showing the change of two illumination areas A _i , A _j in the comparative technology. In the comparative technology of FIG. 9(b), each illumination area A _i , A _j disappears toward its center. In this case, two locally bright points remain, and the multiple illumination areas A _i , A _j are turned off independently and separately, which gives the driver a sense of incongruity. In contrast, in this embodiment, the multiple illumination areas A _i , A _j are turned off in a unified manner as shown in FIG. 9(a), which reduces the sense of incongruity.

In addition, according to the vehicle lamp 100, when several illumination areas are turned on, each illumination area is gradually turned on from the side closest to the reference position regardless of its position, so that an overall sense of unity is created and a sense of discomfort can be reduced. Refer to Figs. 9(a) and (b) with the time axis reversed. In the comparative technology of Fig. 9(b), the plurality of illumination areas A _i and A _j are turned on independently from their respective centers, so that the sense of unity is poor and the driver feels uncomfortable. In contrast, in the embodiment of Fig. 9(a), the plurality of illumination areas A _i and A _j are turned on gradually from a common reference position REF, so that the sense of unity can be enhanced and the sense of discomfort can be reduced.

When switching from high beam to low beam, multiple illumination areas are turned off. In this case, the control shown in Fig. 3 to Fig. 5 may be performed, but other control may also be performed. For example, the brightness of each illumination area may be reduced over time without narrowing the width of the illumination area.

Similarly, when switching from low beam to high beam, multiple illumination areas are turned on. In this case, the control of Figures 6 to 8 may be performed, but other control may also be performed. For example, the brightness of each illumination area may be increased over time without changing the width of the illumination area.

Fig. 10 is a perspective view of a vehicle lamp 100 according to an embodiment. The vehicle lamp 1 in Fig. 10 has a blade-scan type variable light distribution lamp 110, which forms a variety of light distribution patterns in front of the vehicle. The variable light distribution lamp 110 includes a plurality of light-emitting units 112, a scanning optical system 130, and a projection optical system 140.

The plurality of light-emitting units 112 are connected to a lighting circuit (not shown) via connectors 113. The light-emitting units 112 include semiconductor light sources such as LEDs (light-emitting diodes) and LDs (semiconductor lasers). One light-emitting unit 112 constitutes the minimum unit for controlling brightness and turning on and off. One light-emitting unit 112 may be one LED chip (LD chip), or may include multiple LED chips (LD chips) connected in series and/or in parallel.

The scanning optical system 130 receives the emitted beams from the multiple light emitting units 112, and scans the reflected light in the lateral direction (H direction in the figure) in front of the vehicle by repeating periodic motion.

Specifically, the scanning optical system 130 includes a reflector 132 and a motor 134. The reflector 132 is attached to a rotor of the motor 134 and rotates. In this embodiment, two reflectors 132 are provided, and the irradiation spot is scanned twice with one rotation of the motor 134. Therefore, the scanning frequency is twice the number of rotations of the motor. The number of reflectors 132 is not particularly limited.

The projection optical system 140 projects the light emitted from the scan optical system 130 onto a virtual vertical screen in front of the vehicle. The projection optical system 140 can be configured as a reflective optical system, a transmissive optical system, or a combination thereof.

At a given time, the beam of each light-emitting unit 112 is reflected at an angle according to the position of the reflector 132 (rotation angle of the rotor), and the reflected light at that time forms a single irradiation spot on a virtual vertical screen in front of the vehicle. When the position of the reflector 132 changes, the reflection angle changes and the position of the irradiation spot moves.

By rotating the motor 134 of the scanning optical system 130 at high speed, the irradiation spot is scanned over a virtual vertical screen, thereby forming a light distribution pattern in front of the vehicle.

11A is a diagram showing an example of the layout of the plurality of light-emitting units 112. In this embodiment, the number of the plurality of light-emitting units 112 is ten.

The light-emitting units 112 are arranged in two tiers in the height direction, with eight light-emitting units 112_1 to 112_8 arranged in the lower tier and two light-emitting units 112_9 and 112_10 arranged in the upper tier. This allows a high-illuminance area to be formed in the vicinity of the H line on the virtual vertical screen.

FIG. 11B is a diagram showing the horizontal range of illumination areas A ₁ to A ₁₀ covered by a plurality of light-emitting units 112_1 to 112_10.

In this example, the irradiation areas _A3 to A7, A9, and _A10 of the third to _seventh , _ninth , and tenth channels straddle the reference position (0°), the irradiation areas _A1 and _A2 of the first and second channels are located to the left of the reference position (0°), and the irradiation area _A8 of the eighth channel is located to the right of the reference position (0°).

FIG. 12 is a circuit diagram showing a configuration example of the vehicle lamp 100. FIG. 12 shows only a part related to driving the light emitting unit 112 of one channel. The ADB ECU 4 receives the camera information S3 and the vehicle information S2. The ADB ECU 4 detects the situation in front of the vehicle, specifically the positions of targets such as an oncoming vehicle, a preceding vehicle, and a pedestrian, based on the camera information S3. The ADB ECU 4 also detects the current vehicle speed, steering angle, and the like, based on the vehicle information S2. The ADB ECU 4 determines the light distribution pattern to be irradiated in front of the vehicle based on these pieces of information, and transmits control data S1 instructing the light distribution pattern to the vehicle lamp 1. As described above, the control data S1 includes the mode designation data S11 instructing the light distribution mode (basic light distribution pattern) and the light shielding data S12 instructing the range to be shielded.

The lighting circuit 200 controls the light amount (brightness) of the light emitting unit 112 in synchronization with the rotation of the reflector 132 based on the control data S1. The lighting circuit 200 includes a position detector 202, a cycle calculation unit 204, a light amount calculation unit 210, and a driver 220 (114 in FIG. 2). The cycle calculation unit 204 and the light amount calculation unit 210 are referred to as a lamp ECU 206. The lamp ECU 206 can be configured using a microcontroller or a microprocessor, or an ASIC (Application Specified IC). The lamp ECU 206 corresponds to the controller 120 in FIG. 2.

The position detector 202 generates a position detection signal S4 indicating the timing when a predetermined reference point of the reflector 132 passes a predetermined position. For example, the reference point may be the ends (partitions) of the two reflectors 132, the center of each reflector, or any other point.

A Hall element may be attached to the motor 134 that rotates the reflector 132. In this case, the Hall signal from the Hall element has a periodic waveform that corresponds to the rotor position, i.e., the blade position (hereinafter referred to as the blade coordinate). The position detector 202 may detect the timing at which the polarity of the Hall signal is inverted, and specifically may be configured with a Hall comparator that compares a pair of Hall signals.

The period calculation unit 204 calculates the period Tp of the periodic motion of the blade based on the position detection signal S4 from the position detector 202. For example, if the position detection signal S4 is the output of a Hall comparator, the period calculation unit 204 measures the interval (half period) between edges of the position detection signal S4. The period calculation unit 204 can be configured with a counter that counts the interval between edges using a clock signal. The period calculation unit 204 outputs period information S5 indicating the measured period.

The light amount calculation section 210 receives the control data S1 and calculates the amount of light that should be emitted by the light emitting unit 112 at each time based on the position detection signal S4 and the period Tp indicated by the period information S5.

For example, the light amount calculation unit 210 is composed of a microcontroller, a microprocessor, a DSP (Digital Signal Processor), a CPU (Central Processing Unit), an ASIC (Application Specified IC), etc., and includes functional blocks called a position information generator 212 and a light amount controller 214.

The position information generator 212 generates position information S6 indicating the position of the reflector 132 at each time based on the period information S5 and the position detection signal S4. For example, the position information generator 212 may be configured as a counter that is reset at each edge of the position detection signal S4 and counts up (or down) for each unit time obtained by dividing the period Tp by N (N is an integer).

The light amount controller 214 calculates the target light amount (on, off) of the light-emitting unit 112 at each time based on the control data S1 and the position information S6, and generates a light amount command value S7 indicating the target light amount.

The correspondence between the blade coordinate X (i.e., the position information S6) and the irradiation coordinate θ can be derived from the geometric arrangement of the light-emitting unit 112 and the reflector 132. The light amount controller 214 may include a table that holds the correspondence between the position information S6 and the irradiation coordinate θ, or may hold an arithmetic expression that describes the correspondence.

The light amount controller 214 may then convert the data _θL , _θR described by the irradiation coordinate θ included in the control data S1 into blade coordinate data _XL , _XR and determine the light amount at each time. Alternatively, the light amount controller 214 may convert the blade coordinate X indicated by the position information S6 into the irradiation coordinate θ and determine the light amount at each time.

When the period Tp is longer than a predetermined threshold, that is, when the rotation speed of the motor 134 is slow, the light quantity calculation unit 210 preferably turns off the light-emitting unit 112. When the motion period Tp of the reflector 132 is long, turning on the light-emitting unit 112 causes the driver to feel flickering (also called flickering), so in such a situation, turning off the light-emitting unit 112 can prevent discomfort.

For example, the light-emitting unit 112 may be turned off when the scanning frequency of the irradiation spot SP is 50 Hz or less. It is empirically known that flickering is perceptible to the human eye when the scanning frequency is below 50 Hz. When two reflectors 132 are used, it can be said that flickering is not perceptible if the rotation speed of the motor 134 is 1500 rpm or more.

The driver 220 receives the light intensity command value S7 and turns on the light emitting unit 112 so as to obtain the light intensity calculated by the light intensity calculation section 210 at each time.

The above is the configuration of the lighting circuit 200 and the vehicle lamp 1 including the same. Next, the operation thereof will be described.

Fig. 13 is a diagram for explaining the operation of the lighting circuit 200 of Fig. 12. Fig. 13 shows an illumination area A _i of one channel. The horizontal axis can be illumination coordinate θ, blade coordinate X, and time t, which correspond one-to-one. In this example, two points R _OFF1 and R _OFF2 of the illumination area A _i are shaded. For example, the shaded data S12 may include data θ _L1 , θ _R1 , θ _L2 , and θ _R2 indicating both ends of the two shaded areas.

The irradiation spot SP _i indicates a portion illuminated by one light-emitting unit 112_i when the reflector 132 is stopped at a certain position. As the reflector 132 rotates over time, the irradiation spot SP _i is scanned in a direction in which the irradiation coordinate increases. One side (right end) of the irradiation spot SP _i in the scanning direction is called the leading edge LE, and the opposite side (left end) is called the trailing edge TE. In this embodiment, the light amount is controlled based on the coordinate of the leading edge LE.

The motor 134, which positions the reflector 132, rotates at a predetermined rotation speed. For example, the motor 134 rotates at 6000 rpm. However, the rotation speed of the motor 134 cannot be kept completely constant, and the rotation of the motor 134 is not under the control of the lamp ECU 206, and can be said to be in a free-running state. The lamp ECU 206 controls the light-emitting unit 112 while adapting to the state of the motor 134 (reflector 132).

When the position detection signal S4 is asserted at a certain time _t0 , that time is associated with a reference value (for example, 0) of the blade coordinate X, and thereafter, the value of the position information S6 indicating the blade position increases with time. In other words, there is a one-to-one correspondence between time t and the position information S6. The slope is determined from the period Tp of the position detection signal S4 calculated immediately before.

The left end coordinate θ _L and right end coordinate θ _R of the light-blocking regions R _OFF1 and R _OFF2 are converted into blade coordinate X data X _L and X _R. The light amount controller 214 then generates a light amount command value S7 so that the light amount in the light-blocking regions R _OFF1 and R _OFF2 becomes zero.

As shown in FIG. 13, the timing at which the light intensity command value S7 is switched from OFF to ON is shifted from the range of the light-shielded area by ΔX. ΔX is the width of the irradiation spot SP. The reason for this will be explained. In the blade scan method, the irradiation spot SP is scanned to form a light distribution pattern, so the brightness of each point in the irradiation area _Ai is given by the integral value of the irradiation spot SP. Therefore, if the switching from ON to ON is performed based on the coordinate of the leading edge LE, light will be irradiated onto the light-shielded area R _OFF . Therefore, the light intensity controller 214 switches the light-emitting unit 112 from ON to OFF when the coordinate of the leading edge LE becomes the start end (end end of the irradiation area) X _L of the light-shielded area. Also, it is desirable for the light intensity controller 214 to switch the light-emitting unit 112 from OFF to ON when the coordinate of the trailing edge TE becomes the end end (end end of the irradiation area) X _R of the light-shielded area, in other words, when the coordinate of the leading edge LE becomes X _R + ΔX. This allows the light-shielded region R _OFF to be darkened.

The above is the operation of the lighting circuit 200. According to this lighting circuit 200, even if the periodic motion of the reflector 132 is not under the control of the lighting circuit 200, the position of the reflector 132 at each time can be estimated based on the period Tp of the reflector 132 and the position detection signal S4. Then, the position of the irradiation spot SP of the reflected light can be estimated from the estimated position of the reflector 132. Therefore, the light amount of the light emitting unit 112 can be changed from moment to moment in accordance with the change in the position of the reflector 132, and a desired light distribution pattern can be formed.

The present invention has been described above based on an embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present invention. Such modifications will be described below.

(Variation 1)
In the embodiment, when a certain illumination area _Ai is turned on or off when switching the basic light distribution pattern, the control shown in Fig. 3 to Fig. 8 is performed, but this is not limited to the above. For example, the control shown in Fig. 3 to Fig. 8 may be applied to turning on or off an illumination area associated with electronic swivel.

(Variation 2)
3 to 5 may be applied when the illumination area A is turned off, and another control may be applied when the illumination area A is turned on. Conversely, the control of FIGS. 6 to 8 may be applied when the illumination area A is turned on, and another control may be applied when the illumination area A is turned off.

(Variation 3)
In the embodiment, the case where there is an illumination area that does not cross the reference position has been described, but all illumination areas may be designed to cross the reference position. In this case, only the controls in Figs. 3 and 6 are applied.

The present invention has been described using specific terms based on the embodiments, but the embodiments merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments without departing from the spirit of the present invention as defined in the claims.

The present invention relates to a vehicle lamp for use in an automobile or the like.

1 Vehicle lighting fixture 2 Lighting fixture system 4 ADB ECU
S1 Control data S11 Mode designation data S12 Shading data S2 Vehicle information S3 Camera information S4 Position detection signal S5 Period information S6 Position information S7 Light amount command value 100 Vehicle lamp 102 Low beam unit 104 High beam unit 110 Variable light distribution lamp 112 Light emitting unit 114 Driver circuit 120 Controller 130 Scanning optical system 132 Reflector 134 Motor 140 Projection optical system 200 Lighting circuit 202 Position detector 204 Period calculation unit 206 Lamp ECU
210 Light amount calculation unit 212 Position information generator 214 Light amount controller 216 Gradual change controller 220 Driver

Claims (11)

A variable light distribution lamp including a plurality of light-emitting units that can be individually switched on and off, and a scanning optical system that scans the beams of each of the plurality of light-emitting units and illuminates a plurality of illumination areas corresponding to the plurality of light-emitting units;
A controller that controls the variable light distribution lamp and switches the plurality of illumination areas on and off;
Equipped with
When switching an illumination area from on to off, (i) if the illumination area to be switched straddles a reference position, the controller moves the right and left ends of the illumination area toward the reference position;
When switching an illumination area from on to off, the controller:
(ii) when the illumination area to be switched is located to the left of the reference position, the left end of the illumination area is moved toward the right end;
(iii) A vehicular lamp characterized in that, when the illumination area to be switched is located to the right of the reference position, the right end of the illumination area is moved toward the left end. The vehicular lamp according to claim 1, characterized in that, when switching a certain illumination area from off to on, ( iv) if the illumination area to be switched crosses a reference position, the controller widens the illumination area over time, starting from the reference position. When switching an illumination area from off to on, the controller:
(v) if the illumination area to be switched is located to the left of the reference position, the illumination area is expanded over time starting from the right end;
(vi) The vehicular lamp according to claim 2 , wherein when the illumination area to be switched is located to the right of the reference position, the illumination area is expanded over time starting from the left end. 4. The vehicle lamp according to claim 1, wherein when two or more illumination areas are switched from on to off, the transition times of the two or more illumination areas to be switched are equal to each other. A plurality of basic light distribution patterns having different combinations of on and off of the plurality of illumination areas are defined in the controller,
5. The vehicular lamp according to claim 1, wherein the control of (i) is applied when the basic light distribution pattern is switched. 5. The vehicular lamp according to claim 1 , wherein the control of (i) is applied to an illumination area that is switched from on to off in accordance with electronic swivel. A variable light distribution lamp including a plurality of light-emitting units that can be individually switched on and off, and a scanning optical system that scans the beams of each of the plurality of light-emitting units and illuminates a plurality of illumination areas corresponding to the plurality of light-emitting units;
A controller that controls the variable light distribution lamp and switches the plurality of illumination areas on and off;
Equipped with
When switching a certain illumination area from off to on, (iv) if the illumination area to be switched crosses a reference position, the controller widens the illumination area from the reference position over time;
When switching an illumination area from off to on, the controller:
(v) if the illumination area to be switched is located to the left of the reference position, the illumination area is expanded over time starting from the right end;
(vi) A vehicular lamp characterized in that, when the illumination area to be switched is located to the right of the reference position, the illumination area is expanded over time starting from the left end. 8. The vehicular lamp according to claim 7 , wherein when two or more illumination areas are switched from off to on, the transition times of the two or more illumination areas to be switched are equal to each other. A plurality of basic light distribution patterns having different combinations of on and off of the plurality of illumination areas are defined in the controller,
8. The vehicular lamp according to claim 6, wherein the control of (iv) is applied when the basic light distribution pattern is switched. 8. The vehicular lamp according to claim 6, wherein the control of (iv) is applied to an illumination area that is switched from off to on in accordance with electronic swivel. 11. The vehicular lamp according to claim 1, wherein the reference position is a center in a horizontal direction of an entire illumination area.

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