Vehicle lighting system, light distribution controller, and control method for variable light distribution lamp

Abstract

To provide a light distribution controller which can generate a high resolution light distribution pattern.SOLUTION: A light distribution controller 300 controls a light distribution variable lamp including a plurality of pixels arranged in an array. A volatile memory 322 has a first region A1, a second region A2, and a third region A3. A processor 312 executes a software program so that a first layer image L1 stipulating light distribution of high beam can be written in the first region A1 of the memory, a second layer image L2 stipulating a light shield portion of high beam can be written in the second region A2 of the memory, and a third layer image L3 stipulating light distribution of low beam can be written in the third region A3 of the memory. A hardware logic circuit 314 reads the third layer image L3 from the first layer image L1 stored in the memory, synthesizes the third layer image L3 from the first layer image L1, and generates light distribution image data IMG_LD.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle lamp. [Background technology]

[0002] Vehicle lamps are generally capable of switching between low beam and high beam. Low beam illuminates the area around the vehicle with a predetermined illuminance, and light distribution regulations are established to avoid causing glare to oncoming or preceding vehicles, and is primarily used when driving in urban areas. On the other hand, high beam illuminates a wide area ahead and a long distance with relatively high illuminance, and is primarily used when driving at high speeds on roads with few oncoming or preceding vehicles. Therefore, high beam provides better visibility for the driver than low beam, but has the problem of causing glare to drivers of vehicles and pedestrians ahead of the vehicle.

[0003] In recent years, ADB (Adaptive Driving Beam) 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 presence or absence of preceding vehicles, oncoming vehicles, and pedestrians ahead of the vehicle, and reduces the glare on the vehicles or pedestrians by dimming or turning off the lights in the areas corresponding to the vehicles or pedestrians.

[0004] An LED (light-emitting diode) array type ADB lamp has been proposed. Fig. 1 is a block diagram of an LED array type ADB lamp. The ADB lamp 1 includes an LED array 10, a light distribution controller 20, and a power supply circuit 30. The LED array 10 includes a plurality of LEDs 12 arranged in an array, and an LED driver 14 that drives the plurality of LEDs 12. Each LED 12 corresponds to a pixel. The LED driver 14 includes a current source (switch) corresponding to each pixel, and switches each pixel on and off by controlling the on / off of the current source.

[0005] A power supply circuit 30 supplies a power supply voltage VDD to the LED array 10. A light distribution controller 20 generates control signals that specify the on / off state of multiple pixels and transmits them to the LED array 10. The beam emitted from the LED array 10 passes through an optical system (not shown) and is irradiated onto a virtual vertical screen 40. A light distribution pattern 42 corresponding to the on / off state of multiple light-emitting elements 12 is formed on the virtual vertical screen 40. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-172038 Summary of the Invention [Problem to be solved by the invention]

[0007] Problem 1: If the generation process of the light distribution pattern in the light distribution controller 20 is left solely to a software-controlled microcomputer, the LED array 10 cannot be controlled if the microcomputer becomes inoperable.

[0008] Problem 2: In a system in which the resolution of the LED array 10 is low, it is possible to generate a light distribution pattern using a general-purpose microcomputer.

[0009] However, when the resolution of the LED array 10 becomes high (for example, when it exceeds 100×100), a general-purpose microcomputer cannot keep up with the processing, and the architecture of a low-resolution system cannot be used as is.

[0010] The present disclosure has been made in light of the above-mentioned circumstances, and an exemplary purpose of one aspect thereof is to provide a lighting fixture system and a light distribution controller with improved functional safety. Another exemplary purpose of another aspect thereof is to provide a light distribution controller that can generate a high-resolution light distribution pattern. [Means for solving the problem]

[0011] 1. One aspect of the present disclosure relates to a light distribution controller that controls a variable light distribution lamp including a plurality of pixels arranged in an array. The light distribution controller includes a memory, a processor that executes a software program to generate at least one image that defines the light distribution of the variable light distribution lamp and writes the image to the memory, an abnormality detector that detects abnormalities in the processor, and a hardware logic circuit that (i) generates light distribution image data to be output to the variable light distribution lamp based on the at least one image written to the memory when the processor is in a normal state, and (ii) generates light distribution image data based on an auxiliary image generated independently of the processor when the processor is in an abnormal state.

[0012] 2. One aspect of the present disclosure relates to a light distribution controller that controls a variable light distribution lamp including a plurality of pixels arranged in an array. The light distribution controller includes: a memory including a first area, a second area, and a third area; a processor that executes a software program to write a first layer image that defines a high beam light distribution to the first area of ​​the memory, a second layer image that defines a high beam light blocking portion to the second area of ​​the memory, and a third layer image that defines a low beam light distribution to the third area of ​​the memory; and a hardware logic circuit that reads the third layer image from the first layer image stored in the memory and synthesizes the third layer image from the first layer image to generate light distribution image data.

[0013] Any combination of the above components, or mutual substitution of the components or expressions of the present disclosure between methods, devices, systems, etc., are also valid aspects of the present disclosure. [Effects of the Invention]

[0014] According to an aspect of the present disclosure, a high-resolution light distribution pattern can be generated. [Brief explanation of the drawings]

[0015] [Figure 1] This is a block diagram of an LED array type ADB lamp. [Figure 2] 1 is a block diagram of a lighting system according to an embodiment. [Figure 3] FIG. 2 is a block diagram showing the configuration of a light distribution controller. [Figure 4] 4 is a diagram illustrating the operation of the light distribution controller of FIG. 3. FIG. [Figure 5] 10A and 10B are diagrams illustrating a multi-layer compositing process based on alpha blending or additive compositing. [Figure 6] 6(a) and 6(b) are diagrams for explaining the generation of the third layer image. [Figure 7] FIG. 10 is a diagram illustrating high beam light distribution control. [Figure 8] 3 is a diagram showing a headlamp equipped with the lighting system of FIG. 2. FIG. [Figure 9] FIG. 2 is a block diagram related to functional safety of the light distribution controller. [Figure 10] 4 is a flowchart illustrating an operation of the hardware logic circuit according to the first embodiment. [Figure 11] 10 is a flowchart illustrating an operation of the hardware logic circuit according to the second embodiment. [Figure 12] 10 is a flowchart illustrating an operation of the hardware logic circuit according to the third embodiment. [Figure 13] FIG. 13(a) is a diagram showing an ideal low beam light distribution pattern PTN_LO, and FIGS. 13(b) and 13(c) are diagrams showing examples of auxiliary images IMG_AUX. DETAILED DESCRIPTION OF THE INVENTION

[0016] (Outline of the embodiment) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows. It is not intended to limit the scope of the invention or disclosure. This summary is not an exhaustive overview of all possible embodiments, and is not intended to identify key elements of all embodiments or to delineate the scope of some or all aspects. For convenience, the term "one embodiment" may refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0017] A light distribution controller according to one embodiment controls a variable light distribution lamp including a plurality of pixels arranged in an array. The light distribution controller includes a memory, a processor that executes a software program to generate at least one image defining the light distribution of the variable light distribution lamp and writes the image to the memory, an abnormality detector that detects abnormalities in the processor, and a hardware logic circuit that (i) generates light distribution image data to be output to the variable light distribution lamp based on the at least one image written to the memory when the processor is in a normal state, and (ii) generates light distribution image data based on an auxiliary image generated independently of the processor when the processor is in an abnormal state.

[0018] The light distribution controller is capable of generating or acquiring an auxiliary image that defines a simple light distribution without using the processor when the processor is in an abnormal state. Therefore, even when the processor is in an abnormal state, light distribution image data can be generated based on the auxiliary image, and the variable light distribution lamp can be kept lit.

[0019] In one embodiment, the at least one image generated by the processor may include a high beam image that defines a high beam light distribution and a low beam image that defines a low beam light distribution. The hardware logic circuit may combine the high beam image and the low beam image in a normal state of the processor to generate light distribution image data.

[0020] In one embodiment, in an abnormal state of the processor, the hardware logic circuit may write an auxiliary image including a predetermined shape into an area of ​​the memory where the low beam image is written.

[0021] According to this configuration, if an abnormality occurs in the processor, the hardware logic circuit writes an auxiliary image that defines a simple low beam light distribution to memory, and thereafter, light distribution image data can be generated based on the auxiliary image that it has written, thereby maintaining the low beam lighting of the variable light distribution lamp.

[0022] In one embodiment, when the processor is in an abnormal state, the hardware logic circuit may directly output the auxiliary image as light distribution image data without writing it to memory. By reducing memory access, heat generation in the memory can be reduced. When the processor is in an abnormal state due to high temperature, the processor can be prevented from being heated by the memory, and can be cooled in a short time.

[0023] In one embodiment, the anomaly detector may be further configured to detect a memory anomaly. In the event of a memory anomaly, the hardware logic circuit may directly output the auxiliary image as light distribution image data without writing it to the memory. This allows the variable light distribution lamp to continue lighting even in the event of a memory anomaly.

[0024] In one embodiment, the auxiliary image may have pixel values ​​of 0 in the region above a horizontal line passing through the elbow point of the low beam distribution, and pixel values ​​of non-zero in the region below the horizontal line. By simplifying the auxiliary image, the configuration of the hardware logic circuit can be simplified.

[0025] In one embodiment, the pixel values ​​in the lower region of the auxiliary image may be gradually changed in the vertical direction, thereby reducing the sharp difference in brightness near the cutoff line and forming a light distribution that is easy for the driver to see.

[0026] In one embodiment, the pixel values ​​in the lower region of the auxiliary image may be uniform, which further simplifies the configuration of the hardware logic circuit.

[0027] In one embodiment, the pixel values ​​in the lower region of the auxiliary image may be the minimum value of the upper limit value defined for each position within the low beam region, thereby preventing glare during pitching and avoiding situations where nearby areas are too bright and make it difficult to see far away.

[0028] The abnormality detector may be a microcomputer. When the microcomputer detects an abnormality, it may receive an instruction to turn on or off the low beams from a higher-level controller and control a hardware logic circuit.

[0029] The processor may write a shading image that defines a shading portion of the high beam to the memory. The hardware logic circuit may generate light distribution image data based on the high beam image, the low beam image, and the shading image.

[0030] A vehicle lighting system according to one embodiment may include a light distribution controller and a variable light distribution lamp that is controlled based on a light distribution pattern generated by the light distribution controller.

[0031] A light distribution controller according to one embodiment controls a variable light distribution lamp including a plurality of pixels arranged in an array. The light distribution controller includes: a memory including a first region, a second region, and a third region; a processor capable of executing a software program to write a first layer image defining a high beam light distribution into the first region of the memory, a second layer image defining a high beam light blocking portion into the second region of the memory, and a third layer image defining a low beam light distribution into the third region of the memory; and a hardware logic circuit that reads the third layer image from the first layer image stored in the memory and synthesizes the third layer image from the first layer image to generate light distribution image data.

[0032] In this configuration, the processor performs pre-processing to generate the third layer image separately from the first layer image that defines the high beam, the high beam shaded area, and the low beam, and the hardware logic circuit performs post-processing to synthesize the third layer image from the first layer image, which reduces the processor load and makes it possible to generate a high-resolution light distribution pattern.

[0033] Each pixel of the second layer image may include an alpha value indicating the transparency of the corresponding pixel of the first layer image. The hardware logic circuit may composite the first layer image and the third layer image based on the alpha value of the second layer image. The composite may be alpha blended or additive composite.

[0034] The alpha value of the second layer image may be gradually changed at the boundary of the light-blocked area, thereby suppressing abrupt changes in luminance at the boundary of the light-blocked area and reducing the sense of incongruity.

[0035] The processor may generate the third layer image based on a reference image that defines the basic light distribution of the low beam. By generating the reference image in advance and then processing and correcting it to generate the third layer image, the amount of calculation by the processor can be reduced compared to when the third layer image is generated from scratch each time.

[0036] The reference image covers an area wider than the illumination range of the low beam, i.e., the illumination range of the variable light distribution lamp, and the processor may crop a part of the reference image to generate the third layer image.

[0037] The reference image may cover an area wider than the low beam illumination range at least in the horizontal direction, and the processor may achieve electronic swivel by changing the horizontal crop position of the reference image.

[0038] The reference image may cover an area wider than the low beam illumination range at least in the vertical direction, and the processor may achieve the leveling adjustment by changing the vertical crop position of the reference image.

[0039] The light distribution controller may further include a non-volatile memory for storing the reference image.

[0040] The memory may further include a fourth area. The processor may write a fourth layer image that defines the high beam light distribution to the fourth area of ​​the memory. The hardware logic circuit may generate light distribution image data by synthesizing the fourth layer image from the first layer image stored in the memory. There are cases where it is desired to change the high beam light distribution to suit various driving scenes. In this case, a base light distribution that is independent of the driving scene is defined as the first layer image, and an adaptive light distribution that is dependent on the driving scene is defined as the fourth layer image, and by synthesizing these, it is possible to generate light distributions that are suitable for various driving scenes. This makes it possible to reduce memory capacity compared to preparing individual light distributions (first layer images) for each driving scene.

[0041] The processor may generate a pattern to be drawn in the fourth layer image by scaling the pattern to be drawn in the first layer image. For example, the processor may generate a fourth layer image by reducing the first layer image in the horizontal direction and combine the fourth layer image with the original first layer image. This allows for the formation of a light distribution suitable for high-speed driving.

[0042] (Embodiment) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, the embodiments are examples and do not limit the disclosure and invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the disclosure and invention.

[0043] 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 between them or that do not impair the function or effect achieved by their connection.

[0044] Similarly, "a state in which component C is provided between component A and component B" includes not only cases in which components A and C, or components B and C, are directly connected, but also cases in which they are indirectly connected via other components that do not substantially affect the electrical connection state between them or impair the functions or effects achieved by their combination.

[0045] 2 is a block diagram of a lighting system 100 according to an embodiment. The lighting system 100 is an ADB lamp, and includes a host controller 102, an adjustable light distribution lamp 200, and a light distribution controller 300.

[0046] The variable light distribution lamp 200 includes a plurality of pixels PIX arranged in an array. For example, the variable light distribution lamp 200 includes an LED array device 210 and an interface circuit 220. The LED array device 210 is an array of a plurality of light-emitting pixels PIX, and each pixel PIX can be individually switched on (lit) and off (unlit). The pixel PIX can include, for example, a semiconductor light-emitting element such as an LED, and a current source that supplies a drive current to the semiconductor light-emitting element.

[0047] The beam emitted from the LED array device 210 passes through an optical system (not shown) and is irradiated onto a virtual vertical screen 40. A light distribution pattern 42 corresponding to the on / off states of the multiple light-emitting pixels PIX is formed on the virtual vertical screen 40. In this embodiment, the variable light distribution lamp 200 is used for both high beam and low beam, and the beam emitted from the LED array device 210 covers both the high beam illumination area and the low beam illumination area.

[0048] The interface circuit 220 receives light distribution image data IMG_LD that defines the light distribution pattern 42 from the light distribution controller 300. The interface circuit 220 then controls the on / off of each pixel of the LED array device 210 based on the light distribution image data IMG_LD.

[0049] PWM control is used to express the luminance gradation of the pixels PIX of the LED array device 210. Each pixel of the light distribution image data IMG_LD may represent the luminance value (gradation value) of the pixel PIX. The interface circuit 220 may generate a PWM signal having a duty cycle corresponding to each pixel value of the light distribution image data IMG_LD, and control the on / off of the corresponding pixel PIX. In other words, the interface circuit 220 has the function of a PWM controller.

[0050] The light distribution controller 300 is supplied with information INFO necessary for generating the light distribution pattern 42, in addition to a lighting command CMD from the host controller 102. The host controller 102 may be an ECUECU (Electronic Control Unit) on the vehicle side, or an ECU on the lamp side. Specifically, a lighting command CMD instructing to turn on or off the low beam or high beam is input from the host controller 102 to the light distribution controller 300.

[0051] Furthermore, the information INFO supplied by the upper controller 102 to the light distribution controller 300 may include surrounding environment information and vehicle information. The surrounding environment information may include (i) information about landmarks such as preceding vehicles, oncoming vehicles, pedestrians, signs, and delineators, (ii) road information (information about the classification of the road as a highway, general road, suburban area, urban area, etc., and whether the road is straight or curved), and (iii) information about the weather, visibility, road surface condition, etc. The vehicle information may include the vehicle speed, steering angle, vehicle lean angle, etc.

[0052] 3 is a block diagram showing the configuration of the light distribution controller 300. The vehicle bus interface 302 is a CAN (Controller Area Network) or a LIN (Local Interconnect Network), and is provided for communication with the upper controller 102 and other devices.

[0053] Based on information INFO from the upper controller 102, the light distribution controller 300 generates light distribution image data IMG_LD that defines the light distribution pattern 42 and transmits it to the variable light distribution lamp 200. The light distribution controller 300 and the variable light distribution lamp 200 are connected via a serial interface for images, such as HDMI (High-Definition Multimedia Interface, registered trademark).

[0054] When transmitting a larger amount of data between the host controller 102 or other devices, a broadband interface 304 may be provided. The broadband interface 304 may use Ethernet (registered trademark) or the like.

[0055] The output interface 306 transmits the light distribution image data IMG_LD generated by the signal processing unit 310. The output interface 306 is an HDMI interface (transmitter) or another video interface.

[0056] The light distribution controller 300 includes a signal processing unit 310 that generates light distribution image data IMG_LD. The signal processing unit 310 includes a processor 312 and a hardware logic circuit 314. The signal processing unit 310 may be a system-on-a-chip (SOC). The oscillator 308 generates a clock signal and supplies it to the processor 312 and the hardware logic circuit 314. The processor 312 and the hardware logic circuit 314 operate in synchronization with the clock signal.

[0057] The processor 312 receives the lighting command CMD and information IMFO via the vehicle bus interface 302 and the broadband interface 304 .

[0058] Nonvolatile memory 320 is a flash memory, a ROM (Read Only Memory), a ferroelectric memory, a magnetoresistive RAM, or the like, and stores software programs to be executed by processor 312. Processor 312 executes the programs loaded from nonvolatile memory 320 and performs part of the processing for generating light distribution image data IMG_LD.

[0059] Volatile memory 322 is used by signal processing unit 310 to store software programs loaded from processor 312, and is also used as video memory for storing images and data necessary for generating light distribution image data IMG_LD. Volatile memory 322 is a RAM (Random Access Memory) such as DRAM (Dynamic RAM) or SDRAM (Synchronous DRAM). Volatile memory 322 includes a video memory area, and the video memory area includes first area A1 to third area A3.

[0060] By executing a software program, the processor 312 writes a first layer image L1 that defines the light distribution of the high beam to a first area A1 of the volatile memory 322, writes a second layer image L2 that defines the shading portion of the high beam to a second area A2 of the volatile memory 322, and writes a third layer image L3 that defines the light distribution of the low beam to a third area A3 of the volatile memory 322.

[0061] The hardware logic circuit 314 is a programmable logic device that allows a designer to define and change logic circuits. The hardware logic circuit 314 reads out the first layer image L1 to the third layer image L3 from the first area A1 to the third area A3 of the volatile memory 322, and synthesizes the first layer image L1 to the third layer image L3 to generate the light distribution image data IMG_LD.

[0062] The hardware logic circuit 314 may be configured as an ASIC (Application Specific Integrated Circuit).

[0063] The monitoring microcomputer 324 monitors the operating status of each block of the light distribution controller 300 and determines whether or not there is an abnormality. If the monitoring microcomputer 324 detects an abnormality in the processor 312, the hardware logic circuit 314, the oscillator 308, or the output interface 306, it transmits an error signal ERR to the upper controller 102 via the vehicle bus interface 302.

[0064] The above is the configuration of light distribution controller 300. Next, the operation of light distribution controller 300 will be described. FIG. 4 is a diagram illustrating the operation of light distribution controller 300 of FIG. 3. FIG. 5 is a diagram illustrating multi-layer synthesis processing based on alpha blending or additive synthesis. First layer image L1 to third layer image L3 are image data having the same resolution as LED array device 210 of variable light distribution lamp 200.

[0065] The first layer image L1 defines a high beam light distribution pattern PTN_HI. The second layer image L2 defines a high beam shaded portion SHD. The third layer image L3 defines a low beam light distribution pattern PTN_LO. These images are generated by the processor 312 executing a software program and written to the first area A1 to the third area A3 of the video memory of the volatile memory 322. The pixel values ​​of the first layer image L1 and the third layer image L3 correspond to the luminance values ​​(duty cycles in PWM control) of the corresponding light-emitting elements 212.

[0066] The hardware logic circuit 314 synthesizes the layer images L1 to L3 written in the first area A1 to third area A3 to generate the light distribution image data IMG_LD. Several examples of the image synthesis process will be described.

[0067] (First Example) The second layer image L2 defining the shading portion SHD is, in the simplest terms, 1-bit monochrome image data, where a value of 0 corresponds to shading and a value of 1 corresponds to illumination, with pixel values ​​inside the shading portion SHD being 0 and pixel values ​​outside being 1.

[0068] In this case, the hardware logic circuit 314 can generate light distribution image data IMD_LD for the values ​​of corresponding pixels in the first layer image L1 to the third layer image L3 based on the following arithmetic expression (1). IMD_LD[x,y]=L1[x,y]×L2[x,y]+L3[x,y] …(1) Li[x,y] represents the pixel value at position [x,y] of the i-th layer image. This calculation ensures that the shading part SHD does not affect the low beam light distribution.

[0069] (Second Example) In the first embodiment, the difference between light and dark is large at the boundary of the shaded portion SHD, which may make it difficult for the driver to see. Therefore, the second layer image L2 may be multi-bit (m-bit) image data, and image synthesis may be performed based on the alpha blending technique. In this case, each pixel value L2[x,y] of the second layer image L2 represents an alpha value. If m=8, pixels in the shaded portion with a pixel value L2[x,y] of 0 are completely shaded, and the degree of shading decreases as the pixel value increases. Alpha blending is expressed by the following equation (2). IMD_LD[x,y]=(L1[x,y]-L3[x,y])×(L2[x,y] / (2m-1))+L3[x,y] …(2)

[0070] According to this method, by gradually changing the pixel values ​​of the second layer image L2 at the boundary of the light-shielded portion SHD, it is possible to suppress the difference in brightness at the boundary.

[0071] (Third Example) In the third embodiment, similarly to the second embodiment, the second layer image L2 represents an alpha value, but the additive synthesis represented by equation (3) is used for the calculation. IMD_LD[x,y]=L1[x,y]×(L2[x,y] / (2m-1))+L3[x,y] …(3)

[0072] 4 and 5 show the case where high beam and low beam are illuminated simultaneously, but if only low beam is illuminated, the pixel values ​​of the first layer image L1 should be set to 0. Also, if there are no preceding or oncoming vehicles, all pixel values ​​of the second layer image L2 should be set to 255.

[0073] The above is the operation of light distribution controller 300. According to this light distribution controller 300, pre-processing for individually generating first layer image L1, second layer image L2, and third layer image L3 that define high beam, high beam shaded portion, and low beam is performed by software control by processor 312, and post-processing for synthesizing first layer image L1 and third layer image L3 is performed by hardware logic circuit 314. This reduces the load on processor 312 and makes it possible to generate a high-resolution light distribution pattern. Furthermore, by decomposing the elements of light distribution image data into three layer images L1 to L3, various modifications and applications become possible, as will be described later.

[0074] Furthermore, by representing the high beam light distribution using two layers, the first layer image L1 and the second layer image L2, when moving only the shading portion, it is only necessary to update the second layer image L2, and there is no need to update the first layer image L1, thereby reducing the load on the processor 312.

[0075] Next, the generation process of the third layer image L3 will be described. FIGS. 6(a) and 6(b) are diagrams for explaining the generation of the third layer image. FIG. 6(a) shows a reference image IMG_REF that defines the basic light distribution of the low beam. The reference image IMG_REF shown in FIG. 6(a) is an image that defines the Z-shaped light distribution of the low beam. This reference image IMG_REF has a larger number of pixels in the horizontal direction than the third layer image L3, and therefore covers a wider area than the low beam illumination range. The reference image IMG_REF may be stored in the non-volatile memory 320 of FIG. 3. Alternatively, when the light distribution controller 300 is started, the processor 312 may draw the reference image IMG_REF based on a software program and store it in the volatile memory 322. The processor 312 generates the third layer image L3 by cropping a portion of the reference image IMG_REF.

[0076] 6(b) shows the third layer image L3 when each of the horizontal ranges H1 and H2 is cropped. This method can significantly reduce the amount of calculation required for the processor 312 to render the third layer image L3.

[0077] For example, the processor 312 may determine the cropping range based on the steering angle included in the vehicle information from the upper controller 102, road information (such as whether the road is straight or curved), etc. This makes it possible to realize an electronic swivel function.

[0078] Similarly, the reference image IMG_REF may cover a wider area in the vertical direction than the low beam illumination range. The processor 312 may achieve leveling adjustment by changing the vertical crop position of the reference image IMG_REF.

[0079] Next, we will explain high beam light distribution control. When driving on a highway, it is sometimes desirable to form a light distribution with a brighter illumination area concentrated in the center. If multiple reference images that define high beams are prepared for each driving scene, the capacity of the nonvolatile memory increases, which leads to increased costs.

[0080] Therefore, the following processing may be performed to switch the high beam light distribution in accordance with the driving scene. Figure 7 is a diagram illustrating high beam light distribution control. To switch or control the high beam light distribution, a new fourth layer image L4 is added, and the volatile memory 322 further includes a fourth area A4 for storing the fourth layer image L4.

[0081] Processor 312 writes fourth layer image L4, which defines the high beam light distribution, to fourth area A4. Fourth layer image L4 represents a pattern PTN_HI_ADD to be added to the basic high beam light distribution defined by first layer image L1, and from another perspective, it can be understood as the difference between the high beam light distribution according to the driving scene and the basic high beam light distribution.

[0082] The hardware logic circuit 314 generates light distribution image data IMG_LD by synthesizing the first layer image L1 to the fourth layer image L4. In this case, the second layer image L2 acts on both the first layer image L1 and the fourth layer image L4. If the third layer image L3 is 1 bit, synthesis may be performed based on equation (1'). IMD_LD[x,y]=(L1[x,y]+L4[x,y])×L2[x,y]+L3[x,y] …(1')

[0083] When the third layer image L3 represents an alpha value, synthesis may be performed based on equation (2') or (3'). IMD_LD[x,y]=(L1[x,y]+L4[x,y]-L3[x,y])×(L2[x,y] / (2m-1))+L3[x,y] …(2') IMD_LD[x,y]=(L1[x,y]+L4[x,y])×(L2[x,y] / (2m-1))+L3[x,y] …(3')

[0084] According to this method, by rewriting the fourth layer image L4 depending on the driving scene, it is possible to generate a light distribution suitable for various driving scenes.

[0085] The additional pattern PTN_HI_ADD to be drawn in the fourth layer image L4 may be stored in the nonvolatile memory 320.

[0086] Alternatively, the additional pattern PTN_HI_ADD to be drawn in the fourth layer image L4 may be generated by scaling the pattern PTN_HI to be drawn in the first layer image L1. In the example of Fig. 7, the additional pattern PTN_HI_ADD is generated by compressing the pattern PTN_HI in the horizontal direction. This eliminates the need to store the additional pattern PTN_HI_ADD in the nonvolatile memory 320, thereby suppressing an increase in the capacity of the nonvolatile memory 320.

[0087] The position where the additional pattern PTN_HI_ADD is drawn may be shifted depending on the steering and curve conditions.

[0088] (Variation 1) The configuration of the variable light distribution lamp 200, which is the object of control by the light distribution controller 300, is not particularly limited. For example, the variable light distribution lamp 200 may include a light source that generates a beam with a uniform intensity distribution and a spatial light modulator that patterns the intensity distribution of the light source. Examples of the spatial light modulator include a DMD (Digital Micromirror Device) and a liquid crystal panel.

[0089] (Variation 2) The method of transmitting the light distribution image data IMG_LD from the light distribution controller 300 to the variable light distribution lamp 200 is not particularly limited. For example, if the pixel values ​​of the light distribution image data IMG_LD are n bits (2n gradations), the light distribution image data IMG_LD may be decomposed into 2n 1-bit subframes and transmitted. Each pixel in the 2n subframes takes on a value of 1 or 0, and the appearance ratio of the values ​​1 and 0 (i.e., the duty cycle) varies depending on the corresponding pixel value of the light distribution image data IMG_LD. For each pixel in a subframe, the variable light distribution lamp 200 turns on the corresponding pixel of the LED array device 210 when the value is 1, and turns off the corresponding pixel of the LED array device 210 when the value is 0. In other words, the light distribution controller 300 has the function of a PWM controller.

[0090] FIG. 8 is a diagram showing a headlamp 600 equipped with the lighting fixture system 100 of FIG. 2. The headlamp 600 includes an adjustable light distribution lamp 200 and an image sensor 500. The light distribution to be generated by the adjustable light distribution lamp 200 (particularly the light-blocked portion, i.e., the second layer image L2) can be generated based on an image captured by the image sensor 500. The light distribution controller 300 may be housed within a housing 602 of the headlamp 600 or may be provided externally. The headlamp 600 also includes turn signals 606 and position signals 608. If it is difficult to generate a complete low-beam light distribution using only the LED array device 210 due to limitations on the illumination area that the LED array device 210 can cover, an auxiliary low-beam light source 604 that illuminates a wider area may be added.

[0091] (functional safety) Next, functional safety in the light distribution controller 300 will be described.

[0092] 9 is a block diagram relating to the functional safety of the light distribution controller. The basic configuration of the light distribution controller 300A is as described with reference to FIG.

[0093] The processor 312 executes a software program to generate at least one image that defines the light distribution of the variable light distribution lamp 200 and writes the image to the volatile memory 322. In this embodiment, the images generated by the processor 312 include a high beam image that defines the light distribution of the high beam and a low beam image that defines the light distribution of the low beam. The high beam image IMG_HI can be associated with the first layer image L1 and second layer image L2 (and fourth layer image L4) in the above description, and the low beam image IMG_LO can be associated with the third layer image L3.

[0094] When the processor 312 is in a normal state, the hardware logic circuit 314 generates light distribution image data IMG_LD based on the high beam image IMG_HI and the low beam image IMG_LO written to the volatile memory 322. The hardware logic circuit 314 includes a synthesis processing unit 316 and an auxiliary image development unit 318. The synthesis processing unit 316 synthesizes the low beam image IMG_LO and the high beam image IMG_HI to generate light distribution image data IMG_LD.

[0095] In order to achieve the functional safety effects described here, the layer configuration is not limited to those shown in Figures 4 and 7, but at least the image describing high beam and the image describing low beam must be written separately in different areas of the volatile memory 322.

[0096] 4 and 7, the processor 312 may write three (or four) layer images L1 to L3 (L4) as a high beam image IMG_HI and a low beam image IMG_LO to the volatile memory 322. In this case, the synthesis processing unit 316 is configured to be able to synthesize a plurality of layer images based on the above-mentioned arithmetic expression.

[0097] In another example, the processor 312 may generate a high beam image IMG_HI with the shaded portions removed and write it to the volatile memory 322 together with the low beam image IMG_LO. That is, the processor 312 may execute a synthesis process for the first layer image L1 and the second layer image L2. In this case, the synthesis processing unit 316 may synthesize the high beam image IMG_HI and the low beam image IMG_LO to generate the light distribution image data IMG_LD. IMG_LD[x,y]=IMG_HI[x,y]+IMG_LO[x,y]

[0098] The monitoring microcomputer 324 is an abnormality detector that can detect an abnormality in the processor 312. When the processor 312 is normal, the processor 312 receives a low beam or high beam turn-on command CMD from the upper controller 102, but when an abnormality occurs in the processor 312, the processor 312 can receive a control signal CNT corresponding to the turn-on command CMD from the upper controller 102. The control signal CNT may be received via the vehicle bus interface 302 or via a straight line (not shown).

[0099] When the monitoring microcomputer 324 detects an abnormality in the processor 312, the operation of the processor 312 stops. There are no particular limitations on the method for detecting the abnormality, and any known technique, such as a method using a watchdog timer, may be used. When the monitoring microcomputer 324 detects an abnormality in the processor 312, it notifies the hardware logic circuit 314.

[0100] The auxiliary image development unit 318 of the hardware logic circuit 314 is configured to be able to generate or acquire the auxiliary image IMG_AUX without relying on the processor 312 when the processor 312 is in an abnormal state. The hardware logic circuit 314 generates the light distribution image data IMG_LD based on the auxiliary image IMG_AUX.

[0101] If the hardware logic circuit 314 is a programmable logic circuit, the auxiliary image development unit 318 may include a pattern generator configured by a combination of counters and logic gates. It is desirable for the auxiliary image IMG_AUX to approximate the light distribution of a normal low beam, but due to limitations in available hardware, in practice the light distribution of a low beam may be a simplified version.

[0102] The above is the configuration of light distribution controller 300A. This light distribution controller 300A is capable of generating or acquiring auxiliary image IMG_AUX that defines a simple light distribution without using processor 312 when processor 312 is in an abnormal state. Therefore, when processor 312 is in an abnormal state, light distribution image data IMG_LD can be generated based on auxiliary image IMG_AUX, and the lighting of variable light distribution lamp 200 can be maintained.

[0103] Next, some examples of the operation of the light distribution controller 300A in an abnormal state will be described.

[0104] Example 1 The auxiliary image development unit 318 of the hardware logic circuit 314 writes the auxiliary image IMG_AUX including a predetermined shape into the area of ​​the volatile memory 322 where the low beam image IMG_LO is written.

[0105] After the auxiliary image development unit 318 develops the auxiliary image IMG_AUX in the volatile memory 322, the synthesis processing unit 316 generates light distribution image data IMG_LD based on the auxiliary image IMG_AUX.

[0106] In an abnormal state, the synthesis processing unit 316 outputs the auxiliary image IMG_AUX read from the volatile memory 322 as the light distribution image data IMG_LD without modification.

[0107] 10 is a flowchart illustrating the operation of the hardware logic circuit 314 according to the first embodiment. When the processor 312 is in a normal state (Y in S100), the hardware logic circuit 314 combines the high beam image IMG_HI and the low beam image IMG_LO of the processor 312 to generate light distribution image data IMG_LD (S102). The light distribution image data IMG_LD is output to the variable light distribution lamp 200 (S104).

[0108] When the processor 312 is in an abnormal state (N in S100), the monitoring microcomputer 324 determines whether the low beam switch is on (S106). When the low beam switch is off (N in S106), the process returns to S100. When the low beam switch is on (Y in S106), the hardware logic circuit 314 loads the auxiliary image IMG_AUX into the volatile memory 322 (S108). Then, the auxiliary image IMG_AUX read from the volatile memory 322 is set as the light distribution image data IMG_LD (S110).

[0109] Note that the expansion of the auxiliary image IMG_AUX into the volatile memory 322 (S108) needs to be performed only once, and can be skipped from the second time onwards.

[0110] Example 2 The auxiliary image development unit 318 writes the auxiliary image IMG_AUX to the volatile memory 322, erases the area where the high beam image IMG_HI is written, and resets the pixel value to 0. The synthesis processing unit 316 performs the same processing as in the normal state. As a result, the high beam image IMG_HI, whose pixel value is 0, and the auxiliary image IMG_AUX, which was written in place of the low beam image IMG_LO, are synthesized, and the light distribution image data IMG_LD becomes the same as the auxiliary image IMG_AUX.

[0111] 11 is a flowchart illustrating the operation of the hardware logic circuit 314 according to the second embodiment. When the processor 312 is in a normal state (Y in S200), the hardware logic circuit 314 combines the high beam image IMG_HI and the low beam image IMG_LO of the processor 312 to generate light distribution image data IMG_LD (S202). The light distribution image data IMG_LD is output to the variable light distribution lamp 200 (S204).

[0112] When the processor 312 is in an abnormal state (N in S200), it is determined whether the low beam switch is on (S206). When the low beam switch is off (N in S206), the process returns to S200. When the low beam switch is on (Y in S206), the hardware logic circuit 314 expands the auxiliary image IMG_AUX in the area of ​​the low beam image IMG_LO in the volatile memory 322 (S208). It also resets the area of ​​the high beam image IMG_HI in the volatile memory 322 (S210). Then, it combines the high beam image IMG_HI and the auxiliary image IMG_AUX read from the volatile memory 322 to generate light distribution image data IMG_LD (S212).

[0113] It should be noted that steps S208 and S210 only need to be performed the first time, and can be skipped from the second time onwards.

[0114] Example 3 When the processor 312 is in an abnormal state, the hardware logic circuit 314 directly outputs the auxiliary image IMG_AUX developed by the auxiliary image development unit 318 as light distribution image data IMG_LD without writing it to the volatile memory 322.

[0115] 12 is a flowchart illustrating the operation of the hardware logic circuit 314 according to the embodiment 3. When the processor 312 is in a normal state (Y in S300), the hardware logic circuit 314 combines the high beam image IMG_HI and the low beam image IMG_LO of the processor 312 to generate light distribution image data IMG_LD (S302) and output the data (S304).

[0116] In the third embodiment, the volatile memory 322 is not used, and therefore the auxiliary image IMG_AUX cannot be stored. Therefore, when the processor 312 is in an abnormal state (N in S300) and the low beam switch is on (Y in S306), the auxiliary image processing unit 318 processes the auxiliary image IMG_AUX for each frame rate of the light distribution image data IMG_LD to generate the light distribution image data IMG_LD (S308). If the low beam switch is off (N in S306), the process returns to S300.

[0117] According to the third embodiment, it is possible to reduce access to the volatile memory 322 and reduce heat generation in the volatile memory 322. When the processor 312 is in an abnormal state due to high temperature, it is possible to prevent the processor 312 from being heated by the volatile memory 322, and it is possible to cool the processor 312 in a short time and return it to a normal state.

[0118] The control of the third embodiment is also effective when an abnormality occurs in the volatile memory 322. In this case, the "processor" in step S300 of Fig. 12 should be read as "volatile memory."

[0119] The signal processing unit 310 may switch between the controls of the first to third embodiments depending on the location and cause of the abnormality. For example, when the processor 312 is in an abnormal state, the control of the first or second embodiment may be performed, and when the volatile memory 322 is in an abnormal state, the control of the third embodiment may be performed.

[0120] Furthermore, in a situation where the processor 312 is abnormal and the volatile memory 322 is normal, if the temperature of the light distribution controller 300A is high, the control of the third embodiment may be performed.

[0121] Next, the auxiliary image IMG_AUX will be explained. Fig. 13(a) shows an ideal low beam light distribution pattern PTN_LO, and Figs. 13(b) and (c) show examples of auxiliary image IMG_AUX. Auxiliary image IMG_AUX1 in Fig. 13(b) is an image in which the low beam light distribution is coarser. Auxiliary image IMG_AUX1 in Fig. 13(b) is suitable when there is room in the hardware of the auxiliary image development unit 318 or when the hardware logic circuit 314 is configured with an ASIC.

[0122] The auxiliary image IMG_AUX may be further simplified than that shown in Figure 13(b), and the auxiliary image IMG_AUX in Figure 13(c) is simply a rectangle. More specifically, in the auxiliary image IMG_AUX2, the pixel values ​​in the region R1 above the horizontal line HL passing through the elbow point P of the low beam light distribution pattern PTN_LO are 0, and the pixel values ​​in the region R2 below are non-zero. The auxiliary image IMG_AUX in Figure 13(c) can be expanded in the volatile memory 322 using extremely simple hardware.

[0123] The pixel values ​​in the lower region of the auxiliary image IMG_AUX2 may be uniform. In this case, the pixel values ​​may be the minimum value of the upper limit stipulated by regulations for each position of the low beam light distribution pattern PTN_LO. This prevents glare during pitching and avoids situations where nearby areas are too bright and make it difficult to see distant areas.

[0124] Alternatively, the pixel values ​​in the lower region of the auxiliary image IMG_AUX2 may be gradually changed in the vertical direction, thereby reducing the sharp difference in brightness near the cutoff line and forming a light distribution that is easy for the driver to see.

[0125] Next, a modified example related to functional safety will be described.

[0126] (Variation 1) If the hardware logic circuit 314 can access the nonvolatile memory 320, the auxiliary image IMG_AUX may be stored in the nonvolatile memory 320 and read out.

[0127] (Variation 2) In the embodiment, the processor 312 generates the high beam image IMG_HI and the low beam image IMG_LO separately and then combines them in the hardware logic circuit 314, but this is not limited to this. The processor 312 may generate a single piece of image data that defines the final light distribution of the variable light distribution lamp 200 and write it to the volatile memory 322. In this case, in a normal state, the hardware logic circuit 314 reads the image data from the volatile memory 322 and passes it to the output interface 306 at the subsequent stage. In an abnormal state, the hardware logic circuit 314 passes the auxiliary image IMG_AUX to the output interface 306.

[0128] The embodiments merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments as long as they do not deviate from the spirit of the present invention as defined in the claims. [Industrial Applicability]

[0129] The present invention relates to a vehicle lamp. [Explanation of symbols]

[0130] 100...lighting fixture system, 102...host controller, 300...light distribution controller, 200...variable light distribution lamp, 210...LED array device, 212...light emitting element, 220...interface circuit, 300...light distribution controller, 302...vehicle bus interface, 304...broadband interface, 306...output interface, 308...oscillator, 310...signal processing unit, 312...processor, 314...hardware logic circuit, 320...non-volatile memory, 322...volatile memory, 324...monitoring microcomputer, L1...first layer image, L2...second layer image, L3...third layer image, A1...first region, A2...second region, A3...third region

Claims

1. A light distribution controller for controlling a variable light distribution lamp including a plurality of pixels arranged in an array, a memory including a first area, a second area, and a third area; a processor capable of executing a software program to write a first layer image that defines a high beam light distribution into the first area of ​​a memory, a second layer image that defines a light blocking portion of the high beam into the second area of ​​the memory, and a third layer image that defines a low beam light distribution into the third area of ​​the memory; a hardware logic circuit that reads out the third layer image from the first layer image stored in the memory and synthesizes the third layer image from the first layer image to generate light distribution image data; and A light distribution controller comprising:

2. The light distribution controller described in Claim 1, characterized in that the hardware logic circuit generates light distribution image data by synthesizing all of the first layer image to the third layer image when the high beam is on.

3. each pixel of the second layer image includes an alpha value indicating the transparency of the corresponding pixel of the first layer image; The light distribution controller according to claim 1 , wherein the hardware logic circuit synthesizes the first layer image and the third layer image based on the second layer image.

4. The light distribution controller according to claim 3 , wherein the alpha value of the second layer image gradually changes at the boundary of the light-blocking portion.

5. 5. The light distribution controller according to claim 1, wherein the processor generates the third layer image based on a reference image that defines a basic light distribution of the low beam.

6. the reference image covers an area wider than the illumination range of the low beam; The light distribution controller of claim 5 , wherein the processor generates the third layer image by cropping a portion of the reference image.

7. the reference image covers an area wider than the illumination range of the low beam at least in the horizontal direction, 7. The light distribution controller according to claim 6, wherein the processor realizes electronic swivel by changing a horizontal crop position of the reference image.

8. the reference image covers an area wider than the illumination range of the low beam at least in the vertical direction; 8. The light distribution controller according to claim 6, wherein the processor realizes leveling adjustment by changing a vertical crop position of the reference image.

9. 9. The light distribution controller according to claim 5, further comprising a nonvolatile memory for storing the reference image.

10. the memory further includes a fourth area; the processor writes a fourth layer image defining a light distribution of the high beam into the fourth area of ​​the memory; 10. The light distribution controller according to claim 1, wherein the hardware logic circuit generates the light distribution image data by synthesizing the fourth layer image from the first layer image stored in the memory.

11. The light distribution controller according to claim 10 , wherein the processor generates the pattern to be drawn on the fourth layer image by scaling the pattern to be drawn on the first layer image.

12. A light distribution controller according to any one of claims 1 to 11; a variable light distribution lamp controlled based on the light distribution pattern generated by the light distribution controller; A vehicle lighting system comprising:

13. A method for controlling a variable light distribution lamp including a plurality of pixels arranged in an array, comprising: writing a first layer image defining a high beam light distribution to a first area of ​​a memory under software control by a processor; writing a second layer image defining a shaded portion of the high beam to a second area of ​​the memory under software control by the processor; writing a third layer image defining a low beam light distribution to a third area of ​​the memory under software control by the processor; a step in which a hardware logic circuit synthesizes the third layer image from the first layer image stored in the memory to generate light distribution image data; controlling each of the plurality of pixels of the variable light distribution lamp based on a PWM signal obtained by converting a pixel value of a corresponding pixel in the light distribution image data; A control method comprising:

Images