Control device for variable light distribution lamp, vehicle lamp fitting system, and software program

Abstract

A control device (300) sets the luminance of one or more light emitting pixels corresponding to a vehicle (ROI), among a plurality of light emitting pixels, to a zero value such that a shaded portion (6) is formed corresponding to the vehicle (ROI). When the size of the vehicle (ROI) changes, the control device (300) gradually changes the luminance of some of the plurality of light emitting pixels to reach a target luminance over a predetermined light-increasing transition time period, or gradually changes the luminance of some of the light emitting pixels to reach a zero value over a predetermined light-decreasing transition time period, and then, when the region of interest returns to its original size, the control device (300) gradually changes the luminance of some of the plurality of light emitting pixels to reach a zero value over the light-decreasing transition time period, or gradually changes the luminance of some of the plurality of light emitting pixels to reach a target luminance over the light-increasing transition time period.

Description

Control device for variable-beam lamps, vehicle lighting systems, software programs

[0001] This disclosure relates to vehicle lighting equipment.

[0002] Vehicle lighting systems generally allow switching between low beams and high beams. Low beams illuminate the area immediately surrounding the vehicle with a predetermined illuminance, and their light distribution is regulated to avoid glare to oncoming or preceding vehicles. They are primarily used when driving in urban areas. High beams, on the other hand, illuminate a wide area and a distant area ahead with relatively high illuminance. They are primarily used when driving at high speeds on roads with few oncoming or preceding vehicles. Therefore, while high beams offer superior visibility to the driver compared to low beams, they have the problem of causing glare to drivers of vehicles ahead and pedestrians.

[0003] In recent years, Adaptive Driving Beam (ADB) technology has been proposed, which dynamically and adaptively controls the high beam light distribution pattern based on the conditions around the vehicle. ADB technology detects the area of ​​presence of preceding vehicles and oncoming vehicles (collectively referred to as targets) in front of the vehicle (vehicle ROI), and reduces glare on the vehicle by dimming the area corresponding to the vehicle ROI (referred to as the light-shielding area).

[0004] International Publication WO2024 / 190568A1, International Publication WO2022 / 131043A1, Patent No. 6350402

[0005] High-resolution ADB control is being achieved by utilizing LED arrays and spatial light modulators such as DMDs and liquid crystals. In high-resolution ADB control, targets can be detected by sensors such as cameras and LiDAR (hereinafter referred to as ROI sensors), and the light-shielding area can be controlled with high precision.

[0006] In a certain driving scenario, when an object is detected, a high-beam light distribution is formed that obscures the area corresponding to the object. In this situation, if an error occurs in the ROI sensor or processing unit (hereinafter referred to as a detection system error), and the vehicle loses sight of the object that should be there, the vehicle ROI disappears, and the obscured area corresponding to the object disappears. If the object is detected again immediately afterward, the vehicle ROI is restored, and the obscured area is formed in the area corresponding to the object. In other words, the illumination of the area where the object is located becomes momentarily bright, causing annoyance to the driver of the vehicle. It also momentarily causes glare on the object.

[0007] Furthermore, while there are various algorithms and methods for detecting vehicle ROI, they are fundamentally based on the distribution of light points. When detecting a target based on several light points, if another light point appears in the field of view, it may be mistakenly identified as part of the original target, causing the vehicle ROI to expand instantaneously. When the size of the vehicle ROI expands due to false target detection, the area of ​​light blocking widens, resulting in a problem of the field of view becoming darker.

[0008] This disclosure is made in the context of the present circumstances, and one exemplary purpose is to provide a vehicle lighting device that can reduce the inconvenience caused to the driver when they lose sight of a target that should be ahead or when the vehicle ROI is enlarged due to false detection.

[0009] A part of this disclosure relates to a control device for controlling a variable-beam lamp. The variable-beam lamp includes a plurality of light-emitting pixels and is configured to illuminate a region to be formed with a high-beam light distribution with a beam having an intensity distribution corresponding to the luminance distribution of the plurality of light-emitting pixels. The control device acquires information indicating a region of interest and sets the luminance of the plurality of light-emitting pixels corresponding to the region of interest to zero so that a light-shielding portion is formed corresponding to the region of interest. When the size of the region of interest changes, the control device gradually changes the luminance of some of the plurality of light-emitting pixels so as to reach a target luminance over a predetermined brightness-increasing transition time, or so as to reach zero over a predetermined brightness-decreasing transition time. Thereafter, when the region of interest returns to its original size, the control device gradually changes the luminance of some of the plurality of light-emitting pixels so as to reach zero over a brightness-decreasing transition time, or so as to reach a target luminance over a brightness-increasing transition time.

[0010] Furthermore, any combination of the above components, or any substitution of components or expressions between methods, apparatus, systems, etc., are also valid as embodiments of the present invention or this disclosure. Moreover, the description in this section (means for solving the problem) does not describe all the indispensable features of the present invention, and therefore, subcombinations of these described features may also constitute the present invention.

[0011] This is a block diagram of the lighting system according to Embodiment 1. This diagram illustrates the disappearance of the vehicle ROI due to an error in the detection system. This diagram illustrates the transition of high beam light distribution in conventional ADB control. This waveform diagram shows the change in brightness of the light-emitting pixels corresponding to outside the target range A and inside the target range B, respectively, in conventional ADB control. This diagram illustrates the transition of high beam light distribution in ADB control according to Embodiment 1. This waveform diagram shows the change in brightness of the light-emitting pixels corresponding to outside the target range A and inside the target range B, respectively, in ADB control according to Embodiment 1. This diagram illustrates the generation of a control image by the control device. This is a functional block diagram of the control device. This is a block diagram of the microcontroller. This is a block diagram of the lighting system according to Embodiment 2. This diagram illustrates an example of fluctuation in the size of the vehicle ROI due to false detection of a target. This diagram illustrates the transition of high beam light distribution at the time shown in Figure 11 in conventional ADB control. This waveform diagram shows the change in brightness of the light-emitting pixels corresponding to parts A and B in Figure 12 in conventional ADB control. This is a waveform diagram showing the change in brightness of the light-emitting pixels corresponding to parts A and B in Figure 12 in the ADB control according to Embodiment 2.

[0012] (Outline of Embodiments) An outline of some exemplary embodiments of this disclosure is provided below. This outline is intended to provide a basic understanding of the embodiments and to serve as a prelude to the detailed description that follows later. It simplifies some concepts of one or more embodiments and does not limit the scope of the invention or disclosure. Furthermore, this outline is not a comprehensive overview of all possible embodiments and does not limit the essential components of the embodiments. For convenience, “one embodiment” may be used to refer to one embodiment (example or variation) or more embodiments (example or variation) disclosed herein.

[0013] A control device according to one embodiment controls a variable-beam lamp. The variable-beam lamp includes a plurality of light-emitting pixels and is configured to illuminate a region to be formed with a high-beam light distribution with a beam having an intensity distribution corresponding to the brightness distribution of the plurality of light-emitting pixels. The control device acquires information indicating a region of interest and sets the brightness of the light-shielding pixels among the plurality of light-emitting pixels corresponding to the region of interest to zero so that a light-shielding portion is formed corresponding to the region of interest. When the size of the region of interest changes, the control device gradually changes the brightness of some of the plurality of light-emitting pixels so that it reaches a target brightness over a predetermined brightness-increasing transition time, or gradually changes it to zero over a predetermined brightness-decreasing transition time. Subsequently, when the region of interest returns to its original size, the control device gradually changes the brightness of some of the plurality of light-emitting pixels so that it reaches a zero value over a brightness-decreasing transition time, or gradually changes it to reach a target brightness over a brightness-increasing transition time.

[0014] With this configuration, when the vehicle loses sight of a target that should be ahead, or when the vehicle's ROI is enlarged due to a false detection, the brightness of the light-emitting pixels, i.e., the illumination of the field of view, changes gradually, thus reducing the inconvenience caused to the driver.

[0015] In one embodiment, when a region of interest disappears, the control device may gradually change the brightness of the light-emitting pixel corresponding to the disappeared region of interest over a predetermined brightness-increasing transition time to reach the target brightness at the time of illumination, and when the region of interest returns after disappearing, it may gradually change the brightness of the light-emitting pixel corresponding to the region of interest over a predetermined brightness-decreasing transition time to become zero.

[0016] In this configuration, when the region of interest disappears due to a detection system error, the pixel values ​​of the light-emitting pixels included in the disappeared region of interest do not immediately reach the target brightness, but rather gradually increase in brightness over time. Then, when the detection system error is resolved and the region of interest is restored, the brightness values ​​gradually decrease toward zero. This suppresses changes in illuminance in the area where the target exists when the region of interest disappears due to a detection system error, thereby reducing the inconvenience caused to the driver.

[0017] "Zero luminance" includes not only values ​​where the luminance is exactly zero, but also values ​​that can be considered effectively zero. A value that can be considered effectively zero is a small value that corresponds to a luminance level that does not produce glare.

[0018] A light-emitting pixel refers to a unit of brightness control. Therefore, when a variable-beam lamp is composed of an array of light-emitting elements, each light-emitting element corresponds to a light-emitting pixel. When a variable-beam lamp is composed of spatial light modulators such as DMDs (Digital Mirror Devices) or liquid crystal devices, each of these pixels corresponds to a light-emitting pixel.

[0019] In one embodiment, when the region of interest expands, the control device may gradually change the brightness of the light-emitting pixels corresponding to the expanded portion to reach zero over a predetermined dimming transition time, and when the region of interest shrinks after expansion, it may gradually change the brightness of the light-emitting pixels corresponding to the expanded portion back to its original brightness over a predetermined brightening transition time.

[0020] With this configuration, when the region of interest expands due to a false detection, the pixel values ​​of the light-emitting pixels included in the expanded region do not immediately become zero, but rather gradually darken over time. Then, when the false detection is resolved and the region of interest shrinks, the pixels whose brightness had decreased gradually brighten back up to their original brightness. This allows for a clear field of view to be maintained even when the region of interest expands due to a false detection.

[0021] In one embodiment, the dimming transition time may be equal to or shorter than the brightening transition time.

[0022] In one embodiment, the dimming transition time may be longer than 0 ms and shorter than 1000 ms, and the brightening transition time may be longer than 100 ms and shorter than 2000 ms.

[0023] A vehicle lighting system according to one embodiment may include any of the above-described control devices and a variable-light distribution lamp.

[0024] (Embodiments) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. Furthermore, the embodiments are illustrative and not limiting to the disclosure, and not all features or combinations thereof described in the embodiments are necessarily essential to the disclosure.

[0025] (Embodiment 1) Figure 1 is a block diagram of a lighting system 100 according to Embodiment 1. The lighting system 100 is mounted on an automobile and has the function of a headlamp that illuminates the field of view in front of the vehicle. In high beam mode, the lighting system 100 has an ADB function that blocks light from areas where oncoming vehicles and preceding vehicles (hereinafter collectively referred to as targets) are present, depending on the situation in front of the vehicle.

[0026] Figure 1 shows a virtual vertical screen 2, on which the high-beam light distribution 4 is schematically represented. The high-beam light distribution 4 includes a light-shielding section 6 in the area where the target is located, where the illuminance is substantially zero. Since the position of the target changes moment by moment, the lighting system 100 controls the position of the light-shielding section 6 to follow the target. The area other than the light-shielding section 6 is called the illumination section 8. In other words, the high-beam light distribution 4 includes the light-shielding section 6 and the illumination section 8.

[0027] The lighting system 100 comprises a vehicle lighting fixture 200, a vehicle ECU 110, and an ROI sensor 120. The ROI sensor 120 is a camera, LiDAR, etc., and senses the situation in front of the vehicle. Based on the output of the ROI sensor 120, the vehicle ECU (Electronic Control Unit) 110 detects an object and generates vehicle ROI information (hereinafter referred to as ROI information) that indicates the region of interest where the object exists, in other words, the region that should be shielded from light. The method and algorithm for detecting the object are not particularly limited, and known technology or future available technology can be used.

[0028] ROI information includes positional information for the left, right, top, and bottom edges of the light-shielding area. Typically, this positional information is expressed as an angle.

[0029] The ROI information is transmitted from the vehicle ECU 110 to the vehicle lamp 200 via a vehicle bus such as a CAN (Controller Area Network) or a LIN (Local Interconnect Network). The vehicle lamp 200 performs ADB control using the ROI information when the high beam is on.

[0030] The vehicle lamp 200 includes a light distribution variable lamp 210 and a control device 300. The light distribution variable lamp 210 includes a light emitting device 212. The light emitting device 212 is, for example, an LED array and includes a plurality of light emitting pixels (second pixels) PIX2. The luminance values of the plurality of light emitting pixels PIX2 are set according to the pixel values of the plurality of pixels (first pixels) PIX1 included in the control image IMG1 generated by the control device 300. The light distribution variable lamp 210 irradiates an area on the virtual vertical screen 2 in front of the vehicle where the high beam light distribution 4 should be formed with a beam BM having an intensity distribution according to the luminance distribution of the plurality of light emitting pixels PIX2.

[0031] Based on the ROI information, the control device 300 generates a control image IMG1 that defines the high beam light distribution and controls the luminance of the plurality of light emitting pixels PIX2 of the light distribution variable lamp 210. Among the plurality of pixels PIX1 that make up the control image IMG1, the pixel values of the portion corresponding to the ROI, that is, the portion corresponding to the light shielding portion 6, are zero. As a result, the plurality of light emitting pixels PIX2 corresponding to the light shielding portion 6 are turned off. The light emitting pixels to be turned off are referred to as off pixels. The control device 300 selects, as a plurality of off pixels, those of the plurality of light emitting pixels PIX2 that correspond to the vehicle ROI so that the light shielding portion 6 is formed corresponding to the vehicle ROI.

[0032] The control device 300 updates the control image IMG1, that is, the luminance of the plurality of light emitting pixels PIX2, for each control period T. The control period T is, for example, on the order of several tens of ms to 100 ms. The luminance control method may be analog dimming (analog light control), PWM (Pulse Width Modulation) light control, or a combination thereof.

[0033] During driving, the relative positional relationship between the host vehicle and the object target constantly changes, and the vehicle ROI moves along with the change in the relative positional relationship. By changing the position of the off-pixels following the change in the vehicle ROI, ADB control can be achieved.

[0034] During driving, due to an error in the detection system, the vehicle ROI may instantaneously disappear. The problems caused by errors in the detection system in conventional ADB control are described below.

[0035] FIG. 2 is a diagram for explaining the disappearance of the vehicle ROI due to an error in the object target detection system. FIG. 2 shows the fields of view at times t1, t2, and t3. The left side is the host vehicle lane 900, and the right side is the oncoming vehicle lane 902. In the oncoming vehicle lane 902, an oncoming vehicle, which is the object target 906, is traveling.

[0036] At time t1, the object target 906 is correctly detected, and a vehicle ROI 910 of an appropriate size is generated.

[0037] At time t2, due to an error in the detection system, the object target 906 is no longer correctly detected, and the vehicle ROI 910 disappears. For example, when there is an obstacle (not shown in FIG. 2), such as a median strip, between the oncoming vehicle lane 902 and the host vehicle lane 900, and the light spot of the object target 906 is instantaneously blocked by this obstacle, an error in the detection system occurs, the object target 906 is lost sight of, and the vehicle ROI 910 may disappear.

[0038] At time t3, the object target 906 is correctly recognized again, and the vehicle ROI 910 returns.

[0039] FIG. 3 is a diagram for explaining the transition of the high beam distribution HI in conventional ADB control. Times t1, t2, and t3 correspond to times t1, t, and t3 in FIG. 2, respectively. At time t1, a light-shielding portion 912 is formed corresponding to the correct vehicle ROI 910. At time t2, when the vehicle ROI 910 disappears due to an error in the detection system, the light-shielding portion 912 disappears, so the high beam HI is irradiated onto the object target 906.

[0040] Then, at time t3, when the object target 906 is accurately detected, the vehicle ROI 910 resurrects again at the position corresponding to the object target 906, and the light-shielding portion 912 is formed.

[0041] Figure 4 is a waveform diagram showing the change in brightness of the light-emitting pixels corresponding to the area outside the target 906 (A) and the area within the target 906 (B) in a conventional ADB control.

[0042] Because high beam HI continues to illuminate part A, the brightness of the light-emitting pixels corresponding to part A maintains a non-zero value X. On the other hand, the brightness of the light-emitting pixels corresponding to part B is zero before time t2, becomes a non-zero value Y at time t2, and returns to zero at time t3.

[0043] Thus, with conventional ADB control, when the vehicle ROI disappears and then immediately returns, the illumination of the area where the target 906 is located momentarily brightens, causing annoyance to the driver of the vehicle.

[0044] Returning to Figure 1, we will now explain the control system when the vehicle ROI is lost due to an error in the detection system.

[0045] When the vehicle ROI disappears due to an error in the detection system, the control device 300 gradually changes the brightness of the light-emitting pixel corresponding to the disappeared vehicle ROI over a predetermined brightness-increasing transition time T2 to reach the target brightness when the light is on. Then, when the vehicle ROI returns after disappearing, the control device 300 gradually changes the brightness of the light-emitting pixel corresponding to the vehicle ROI over a predetermined brightness-decreasing transition time T4 to reach zero.

[0046] The above describes the configuration of the lighting system 100 according to Embodiment 1. Next, its operation will be explained.

[0047] Figure 5 is a diagram illustrating the transition of high beam light distribution in ADB control according to Embodiment 1. Times t1, t2, and t3 correspond to the times t1, t2, and t3 in Figure 2. In the ADB control according to this embodiment, at time t2, the brightness of portion B corresponding to the target does not increase instantaneously to a non-zero value Y, but rather increases gradually over time.

[0048] Therefore, the brightness at time t3, when the vehicle ROI is restored, does not rise to a very high level. After the vehicle ROI is restored at time t3, the brightness of part B gradually decreases towards zero. This control suppresses the momentary increase in brightness in the area where the target is located, thereby reducing the annoyance felt by the driver of the vehicle.

[0049] Figure 6 is a waveform diagram showing the change in brightness of light-emitting pixels corresponding to area A outside the target's presence range and area B within the target's presence range, respectively, in the ADB control according to Embodiment 1. The brightness of the light-emitting pixels corresponding to area A maintains a non-zero value X.

[0050] The brightness of the light-emitting pixel corresponding to section B is zero before time t2. When the vehicle ROI disappears at time t2, the brightness of section B increases to a non-zero target value Y at time t5, after a predetermined light-increasing transition time T2.

[0051] When time t2 is the elapsed time and τ is the luminance L of part B during the brightening process. Ｂ (τ) can be expressed by equation (1) using the function p(τ). The function p(τ) is a monotonically increasing function. The function p(τ) is called the brightness control waveform. L Ｂ (τ)=Y×p(τ) …(1) p(0)=0 p(T2)=1

[0052] In the example shown in Figure 6, the function p(τ) is a linear function and is expressed by equation (2), with the luminance increasing at a constant slope. p(τ) = τ / T² …(2)

[0053] The function p(τ) may be a polyline formed by combining multiple straight lines, or it may be defined based on a quadratic function, a cubic function, a trigonometric function, or an exponential function.

[0054] During the brightening period, at time t3, the vehicle ROI returns to normal. The luminance Z at time t3 is Y × p(t3 - t2).

[0055] From time t3 onward, the brightness of part B decreases so that it returns to zero after a predetermined dimming transition time T4.

[0056] When the elapsed time from time t3 is denoted by θ, the luminance L of part B during the brightening is...Ｂ L(θ) can be expressed by Equation (3) using the function q(θ). The function q(θ) is a decreasing and increasing function. The function q(θ) is referred to as a dimming control waveform. Ｂ L(θ) = Z × q(θ) …(3) q(0) = 1 q(T4) = 0

[0057] In the example of FIG. 6, the function q(θ) is a linear function, expressed by Equation (4), and the luminance decreases at a constant slope. q(τ) = 1 - θ / T4 …(4)

[0058] Note that the function q(θ) may be a broken line formed by combining a plurality of straight lines, or may be defined based on a quadratic function, a cubic function, a trigonometric function, or an exponential function.

[0059] It is desirable to determine the dimming transition time T4 and the light increase transition time T2 in consideration of glare suppression and an easy-to-view visual field. Specifically, it is preferable that the relationship T2 ≥ T4 holds. Also, the dimming transition time T4 may be determined within the range of 0 ms to 1000 ms. Also, the light increase transition time T2 may be determined within the range of 100 ms to 2000 ms.

[0060] FIG. 7 is a diagram for explaining the generation of a control image by the control device 300. The control device 300 generates a control image IMG1 by multiplying corresponding pixel values of a reference image IMG2 and a scaling image IMG3. When the pixel value of a certain pixel in the reference image IMG2 is a ｊ , the pixel value of the corresponding pixel in the scaling image IMG3 is b ｊ , and the pixel value of the corresponding pixel in the control image IMG1 is c ｊ , then ｊ c ｊ = a ｊ × b

[0061] The reference image IMG2 defines the illuminance distribution of the basic light distribution when there is no light shielding portion. In other words, the reference image IMG2 defines the pixel values of a plurality of first pixels PIX1 when there is no light shielding portion. The pixel value of the reference image IMG2 corresponds to Y in Equation (1).

[0062] The scaled image IMG3 contains multiple third pixels whose pixel values ​​range from 0 to 1. The pixel values ​​of the third pixels in the scaled image IMG3 are the normalized luminance values ​​in the gradual change control and correspond to the values ​​of the functions p(τ) and q(θ) in equations (1) and (3).

[0063] Figure 8 is a functional block diagram of the control device 300. The control device 300 can be implemented as a microcontroller including a processor capable of executing software programs. Therefore, the block diagram in Figure 8 does not show the hardware configuration of the control device 300, but rather the functions realized by the software program, in other words, the processes that the software program causes the processor to execute and the data described within the software program.

[0064] The control device 300 includes a lookup table 310, a counter 320, a control unit 330, and a multiplier 340.

[0065] The counter 320 can independently control the count for each of the multiple pixels PIX1. When the number of pixels in the control image IMG1 is n, the counter 320 generates n count values ​​d. １ ~d ｎ It can hold n count values ​​d. The counter 320 has n count values ​​d １ ~d ｎ This is incremented with each control cycle. These count values ​​correspond to τ in equation (1) or θ in equation (3).

[0066] The control unit 330 determines that if a certain j-th pixel PIX1 is removed from the vehicle ROI due to the disappearance of the vehicle ROI, the j-th count value d ｊ Reset the count value d to 0. ｊ In other words, time τ increments from 0 to 1. This corresponds to the operation during the period t2 to t5 in Figure 6.

[0067] Furthermore, when the vehicle ROI returns to normal, the control unit 330 determines that the j-th pixel PIX1 returns to the vehicle ROI, and the j-th count value d ｊ Reset the count value d to 0. ｊIn other words, time θ increments from 0 to 1. This corresponds to the operation during the period t3 to t4 in Figure 6.

[0068] The lookup table 310 holds the control waveforms p(τ) and q(θ). The control unit 330 refers to the lookup table 310 and the counter 320 to generate the scaled image IMG3.

[0069] When generating the pixel value of the j-th pixel of the scaled image IMG3, the corresponding j-th count value d of counter 320 ｊ Obtain the following. Then refer to the lookup table 310 and select the control waveform p(τ) or q(θ). Then the count value d ｊ The normalized luminance value x corresponds to ｊ Read out the normalized luminance value x. ｊ This becomes the pixel value of the j-th pixel in the scaled image IMG3.

[0070] The multiplier 340 generates a control image IMG1 by multiplying the corresponding pixel values ​​of the reference image IMG2 and the scaled image IMG3.

[0071] Figure 9 is a block diagram of the microcontroller. The microcontroller 800 comprises a processor 810, a non-volatile memory 820, a memory 830, and an interface circuit 840. The non-volatile memory 820 is flash memory and is a storage medium that stores the aforementioned software program 850 executed by the processor 810. At startup, the processor 810 loads the software program 850 into the memory 830 and executes the instructions of the software program 850. The interface circuit 840 is a UART (Universal Asynchronous Receiver and Transmitter), a 3-wire serial interface, and I ２ This may include serial interfaces such as C-bus interfaces, CAN interfaces, GPIO, A / D converters, and D / A converters. The components of the microcontroller 800 may be integrated into a single IC package, or it may be a microcontroller board in which several IC packages are mounted on a printed circuit board.

[0072] The above is an example of the implementation of the control device 300.

[0073] (Embodiment 2) Figure 10 is a block diagram of the lighting system 100 according to Embodiment 2. The lighting system 100 is mounted on an automobile and has the function of a headlamp that illuminates the field of view in front of the vehicle. In high beam mode, the lighting system 100 has an ADB function that blocks light from areas where oncoming vehicles and preceding vehicles (hereinafter collectively referred to as targets) are present, depending on the situation in front of the vehicle.

[0074] Figure 10 shows a virtual vertical screen 2, on which the high-beam light distribution 4 is schematically represented. The high-beam light distribution 4 includes a light-shielding section 6 in the area where the target is located, where the illuminance is substantially zero. Since the position of the target changes moment by moment, the lighting system 100 controls the position of the light-shielding section 6 to follow the target. The area other than the light-shielding section 6 is called the illumination section 8. In other words, the high-beam light distribution 4 includes the light-shielding section 6 and the illumination section 8.

[0075] The lighting system 100 comprises a vehicle lighting fixture 200, a vehicle ECU 110, and an ROI sensor 120. The ROI sensor 120 is a camera, LiDAR, etc., and senses the situation in front of the vehicle. Based on the output of the ROI sensor 120, the vehicle ECU (Electronic Control Unit) 110 detects an object and generates vehicle ROI information (hereinafter referred to as ROI information) that indicates the region of interest where the object exists, in other words, the region that should be shielded from light. The method and algorithm for detecting the object are not particularly limited, and known technology or future available technology can be used.

[0076] ROI information includes positional information for the left, right, top, and bottom edges of the light-shielding area. Typically, this positional information is expressed as an angle.

[0077] ROI information is transmitted from the vehicle ECU 110 to the vehicle lighting unit 200 via a vehicle bus such as CAN (Controller Area Network) or LIN (Local Interconnect Network). The vehicle lighting unit 200 uses the ROI information to perform ADB control when the high beams are on.

[0078] The vehicle lighting fixture 200 comprises a variable-beam lamp 210 and a control device 300. The variable-beam lamp 210 comprises a light-emitting device 212. The light-emitting device 212 is, for example, an LED array and includes a plurality of light-emitting pixels (second pixels) PIX2. The luminance values ​​of the plurality of light-emitting pixels PIX2 are set according to the pixel values ​​of a plurality of pixels (first pixels) PIX1 included in a control image IMG1 generated by the control device 300. The variable-beam lamp 210 illuminates the area on the virtual vertical screen 2 in front of the vehicle where the high-beam light distribution 4 should be formed with a beam BM having an intensity distribution corresponding to the luminance distribution of the plurality of light-emitting pixels PIX2.

[0079] The control device 300 generates a control image IMG1 that defines the high beam light distribution based on ROI information and controls the brightness of multiple light-emitting pixels PIX2 of the variable light distribution lamp 210. Of the multiple pixels PIX1 that make up the control image IMG1, the pixel value of the portion corresponding to the ROI, that is, the portion corresponding to the light-shielding portion 6, is zero. As a result, the multiple light-emitting pixels PIX2 corresponding to the light-shielding portion 6 are turned off. Light-emitting pixels that should be turned off are called off pixels. The control device 300 selects the multiple light-emitting pixels PIX2 that correspond to the vehicle ROI as multiple off pixels so that the light-shielding portion 6 is formed corresponding to the vehicle ROI.

[0080] The control device 300 updates the brightness of the control image IMG1, in other words, the brightness of multiple light-emitting pixels PIX2, at each control cycle T. The control cycle T is, for example, several tens of ms to about 100 ms. The brightness control method may be analog dimming (analog dimming), PWM (Pulse Width Modulation) dimming, or a combination of the two.

[0081] During driving, the relative positional relationship between the vehicle and the target is constantly changing, and the vehicle's ROI moves in accordance with this change in relative position. ADB control can be realized by changing the position of the off-pixels in accordance with the change in the vehicle's ROI.

[0082] During driving, the size of the vehicle's ROI may change instantaneously due to false detection of an object. This document explains the problems that arise from false detection of objects in conventional ADB control.

[0083] Figure 11 illustrates an example of a variation in the size of a vehicle's ROI caused by false detection of an object. Figure 11 shows the field of view at times t1, t2, and t3. The left side is the vehicle's own lane 900, and the right side is the oncoming lane 902. A preceding vehicle, which is an object 906, is traveling in the vehicle's own lane 900. A delineator 904 is installed on the side of the oncoming vehicle 902.

[0084] At time t1, the target 906 is correctly detected, and a vehicle ROI 910 of the appropriate size is generated.

[0085] At time t2, the target 906 is approaching the light point such as the delineator 904, and the delineator 904 is recognized as part of the target 906, causing the size of the vehicle ROI 910 to expand.

[0086] At time t3, when the target 906 passes the delineator 904, the target 906 is correctly recognized again, and the vehicle ROI 910 returns to its original size.

[0087] Figure 12 illustrates the transition of the high beam light distribution (HI) at times t1, t2, and t3 in Figure 11 in a conventional ADB control system. At time t1, part A, which corresponds to the correctly sized vehicle ROI 910, is obscured. At time t2, when the vehicle ROI 910 expands due to a false detection of a target, the field of view of the expanded part B suddenly becomes dark. Then, at time t3, when the target is accurately detected, light illuminates part B, and the original light distribution returns.

[0088] Figure 13 is a waveform diagram showing the change in brightness of light-emitting pixels corresponding to parts A and B in Figure 12 in a conventional ADB control. Since part A remains shielded from light, the brightness of the light-emitting pixels corresponding to part A remains virtually zero. On the other hand, the brightness of the light-emitting pixels corresponding to part B is a non-zero value X before time t2, becomes zero at time t2, and returns to its original value X at time t3.

[0089] Thus, conventional ADB control had the problem that when targets were misdetected and the vehicle's ROI expanded, the field of view would temporarily become difficult to see.

[0090] Returning to Figure 10, we will now explain the control system when the vehicle's ROI expands due to false target detection.

[0091] When the vehicle ROI expands due to false detection of a target, the control device 300 gradually changes the brightness of the corresponding light-emitting pixel corresponding to the expanded portion B so that it reaches zero over a predetermined dimming transition time T4.

[0092] Then, after the vehicle ROI expands due to false target detection, when the target is detected correctly and the vehicle ROI shrinks, the brightness of the light-emitting pixel corresponding to the expanded portion B is gradually changed toward its original brightness over a predetermined brightness-enhancing transition time T2.

[0093] From another perspective, the control device 300 controls the brightness of multiple light-emitting pixels so that a light-shielding area is formed corresponding to a target (vehicle ahead) when a target (vehicle ahead) is present in front of the vehicle. When a light point such as a delineator is generated to the side of the target, the control device 300 gradually changes the brightness of the light-emitting pixels corresponding to the range B between the target and the light point so that it reaches zero over a predetermined dimming transition time. Then, when the light point disappears, the brightness of the light-emitting pixels corresponding to the range B between the target and the light point is gradually changed back to its original brightness over a predetermined brightening transition time.

[0094] The above describes the configuration of the lighting system 100 according to Embodiment 2. Next, its operation will be explained.

[0095] Figure 14 is a waveform diagram showing the change in brightness of the light-emitting pixels corresponding to parts A and B in Figure 12 in the ADB control according to Embodiment 2. Since part A remains shielded from light, the brightness of the light-emitting pixels corresponding to part A remains substantially zero.

[0096] The brightness of the light-emitting pixel corresponding to section B is a non-zero value X before time t2. As the vehicle ROI expands at time t2, the brightness of section B decreases so that it becomes zero at time t4 after a predetermined dimming transition time T4.

[0097] When time t2 is the elapsed time and τ is the luminance L of part B during dimming, Ｂ(τ) can be expressed by equation (1) using the function f(τ). The function f(τ) is a monotonically decreasing function. The function f(τ) is called the dimming control waveform. L Ｂ (τ)=X×f(τ) …(1) f(0)=1 f(T4)=0

[0098] In the example in Figure 14, the function f(τ) is a linear function and is expressed by equation (2), where the brightness decreases with a constant slope. f(τ) = 1 - τ / T⁴ …(2)

[0099] The function f(τ) may be a polyline formed by combining multiple straight lines, or it may be defined based on a quadratic function, a cubic function, a trigonometric function, or an exponential function.

[0100] At time t3 during the dimming period, the size of the vehicle ROI returns to its original state. The luminance Y at time t3 is X × f(t3 - t2).

[0101] From time t3 onward, the brightness of part B increases so that it returns to its original value X at time t5, after a predetermined light-enhancing transition time T2.

[0102] When the elapsed time from time t3 is denoted by θ, the luminance L of part B during the brightening is... Ｂ (θ) can be expressed by equation (3) using the function g(θ). The function g(θ) is a monotonically increasing function. The function g(θ) is called the brightness control waveform. L Ｂ (θ)=X×g(θ)…(3) g(0)=f(t3-t2)=Y / X g(T2)=1

[0103] In the example in Figure 14, the function g(θ) is a linear function and is expressed by equation (4), where the luminance increases with a constant slope. g(τ) = g(0) + (1 - g(0)) / T² × θ …(4)

[0104] The function g(θ) may be a broken line formed by combining multiple straight lines, or it may be defined based on a quadratic function, a cubic function, a trigonometric function, or an exponential function.

[0105] The above describes the operation of the lighting system 100. Next, I will explain its advantages.

[0106] When the vehicle ROI expands due to a false detection, the pixel values ​​of the light-emitting pixels included in the expanded region B do not immediately become zero, but rather gradually dim over time. Then, when the false detection is resolved and the vehicle ROI shrinks, the pixels whose brightness had decreased gradually brighten back up to their original brightness. This allows for a clear field of view to be maintained even when the range of the vehicle ROI expands due to a false detection.

[0107] The dimming transition time T4 and the brightening transition time T2 should be determined considering glare suppression and a clear field of view. Specifically, it is preferable that the relationship T2 ≥ T4 holds. Furthermore, the dimming transition time T4 should be set in the range of 0 ms to 1000 ms, and the brightening transition time T2 should be set in the range of 100 ms to 2000 ms.

[0108] The embodiments described above are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing steps. Such modifications will be described below.

[0109] In the embodiments, the variable-beam lamp 210 was described as an LED array, but this disclosure is not limited thereto. For example, the variable-beam lamp 210 may be a combination of a light source and a spatial light modulator that patterns the light emitted from the light source. For example, a DMD (Digital Mirror Device) or a liquid crystal device can be used as the spatial light modulator.

[0110] In this embodiment, the case in which the control device 300 is implemented as a microcontroller has been described, but it may also be implemented as an FPGA (Field Programmable Gate Array) or as an ASIC (Application Specific Integrated Circuit).

[0111] While the embodiments described herein have been explained using specific terminology, this explanation is merely illustrative to aid understanding and does not limit the scope of this disclosure or the claims. The scope of the present invention is defined by the claims, and therefore embodiments, examples, and modifications not described herein are also included within the scope of the present invention.

[0112] This disclosure relates to vehicle lighting equipment.

[0113] 100 Lighting system 110 Vehicle ECU 120 ROI sensor 4 High beam light distribution 6 Shading section 8 Irradiation section 200 Vehicle lighting fixture 210 Variable light distribution lamp 212 Light-emitting device PIX2 Light-emitting pixel 300 Control device IMG1 Control image IMG2 Reference image IMG3 Scaling image

Claims

1. A control device for controlling a variable-beam lamp, wherein the variable-beam lamp includes a plurality of light-emitting pixels and is configured to illuminate a region to form a high-beam light distribution with a beam having an intensity distribution corresponding to the brightness distribution of the plurality of light-emitting pixels, the control device acquires information indicating a region of interest, sets the brightness of the plurality of light-emitting pixels corresponding to the region of interest to zero so that a light-shielding portion is formed corresponding to the region of interest, when the size of the region of interest changes, gradually changes the brightness of a portion of the plurality of light-emitting pixels to reach a target brightness over a predetermined brightness-increasing transition time, or gradually changes it to zero over a predetermined brightness-decreasing transition time, and thereafter, when the region of interest returns to its original size, gradually changes the brightness of a portion of the plurality of light-emitting pixels to reach a target brightness over the brightness-decreasing transition time, or gradually changes it to reach a target brightness over the brightness-increasing transition time.

2. The control device according to claim 1, characterized in that when the region of interest disappears, the control device gradually changes the brightness of the light-emitting pixel corresponding to the disappeared region of interest over the brightness-increasing transition time to reach the target brightness at the time of illumination, and when the region of interest returns after disappearing, the control device gradually changes the brightness of the light-emitting pixel corresponding to the region of interest over the brightness-decreasing transition time to become zero.

3. The control device according to claim 2, characterized in that the control device changes the brightness of the light-emitting pixel corresponding to the region of interest with a constant slope.

4. The control device according to claim 1, characterized in that when the region of interest is expanded, the control device gradually changes the brightness of the light-emitting pixel corresponding to the expanded portion so as to reach the zero value over the dimming transition time, and when the region of interest is reduced after being expanded, the control device gradually changes the brightness of the light-emitting pixel corresponding to the expanded portion toward the original brightness over a predetermined brightening transition time.

5. The control device according to claim 5, characterized in that the control device changes the brightness of the light-emitting pixel corresponding to the enlarged portion at a constant slope.

6. The control device according to any one of claims 1 to 5, characterized in that the dimming transition time is equal to or shorter than the brightening transition time.

7. The control device according to any one of claims 1 to 5, characterized in that the dimming transition time is longer than 0 ms and shorter than 1000 ms, and the brightening transition time is longer than 100 ms and shorter than 2000 ms.

8. A vehicle lighting system comprising: a control device according to any one of claims 1 to 5; and the variable light distribution lamp.

9. A program for a control device that controls a variable-beam lamp, wherein the variable-beam lamp includes a plurality of light-emitting pixels and is configured to illuminate a region to form a high-beam light distribution with a beam having an intensity distribution corresponding to the brightness distribution of the plurality of light-emitting pixels, and the program is characterized by causing the processor of the control device to execute: a step of acquiring information indicating a region of interest from a vehicle; a step of setting the brightness of the plurality of light-emitting pixels corresponding to the region of interest to zero so that a light-shielding portion is formed corresponding to the region of interest; a first step of gradually changing the brightness of a portion of the plurality of light-emitting pixels to reach a target brightness over a predetermined brightness-increasing transition time, or to become zero over a predetermined brightness-decreasing transition time, when the size of the region of interest changes; and a second step of gradually changing the brightness of a portion of the plurality of light-emitting pixels to become zero over the brightness-decreasing transition time, or to reach a target brightness over the brightness-increasing transition time, when the region of interest returns to its original size.

10. The program according to claim 9, wherein the first step includes a step of gradually changing the brightness of the light-emitting pixel corresponding to the lost region of interest over a predetermined brightness-increasing transition time to reach the target brightness at the time of illumination when the region of interest has disappeared, and the second step includes a step of gradually changing the brightness of the light-emitting pixel corresponding to the region of interest over a predetermined brightness-decreasing transition time to become zero when the region of interest has disappeared and then returned.

11. The program according to claim 9, wherein the first step includes a step of gradually changing the brightness of the light-emitting pixel corresponding to the enlarged portion when the region of interest is enlarged, so as to reach the zero value over a predetermined dimming transition time, and the second step includes a step of gradually changing the brightness of the light-emitting pixel corresponding to the enlarged portion towards the original brightness over a predetermined brightening transition time when the region of interest is reduced after being enlarged.

12. A control device for controlling a variable-beam lamp, wherein the variable-beam lamp includes a plurality of light-emitting pixels and is configured to illuminate a region to form a high-beam light distribution with a beam having an intensity distribution corresponding to the brightness distribution of the plurality of light-emitting pixels, and the control device controls the brightness of the plurality of light-emitting pixels so that a light-shielding portion is formed corresponding to the target when a target is present in front of the vehicle, and when a light spot occurs to the side of the target, the control device gradually changes the brightness of the light-emitting pixels corresponding to the range between the target and the light spot over a predetermined dimming transition time to reach zero, and thereafter, when the light spot disappears, the control device gradually changes the brightness of the light-emitting pixels corresponding to the range between the target and the light spot towards the original brightness over a predetermined brightening transition time.

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