Vehicle lamp system and light distribution controller

Abstract

A light distribution controller (300A) controls a light distribution variable lamp (200) including a plurality of pixels arranged in an array. The processor (312) generates at least one image defining the light distribution of the variable light distribution lamp (200) by executing a software program, and writes the at least one image to the volatile memory (322). The monitoring microcomputer (324) detects an abnormality in the processor (312). A hardware logic circuit (314, i) generates light distribution image data (IMG - LD) to be output to a light distribution variable lamp from at least one image written by a volatile memory (322) in a normal state of a processor (312), and (ii) generates light distribution image data (IMGLD) from an auxiliary image (IMG - AUX) generated without depending on the processor (312) in an abnormal state of the processor (312).

Description

Technical Field

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

[0002] Vehicle lamps are usually able to switch between low beam and high beam. Low beam is light that illuminates the vicinity of the vehicle at a specified illumination, and the lighting regulations are determined in a way that does not cause glare to oncoming vehicles or vehicles in front, and is mainly used when driving in urban areas. On the other hand, high beam is light that illuminates a wider range in front and far away at a relatively high illumination, and is mainly used when driving at high speeds on roads with fewer oncoming vehicles or vehicles in front. Therefore, compared with low beam, high beam provides better visibility for the driver, and there is a problem of causing glare to drivers of vehicles in front of the vehicle or pedestrians.

[0003] In recent years, an ADB (Adaptive Driving Beam) solution has been proposed to dynamically and adaptively control the high beam light distribution pattern according to the state of the vehicle's surroundings. ADB technology detects the presence of vehicles in front of the vehicle, oncoming vehicles, or pedestrians, and dims or turns off the light in the area corresponding to the vehicle or pedestrian, thereby reducing the glare caused to the vehicle or pedestrian.

[0004] As an ADB lamp, a lamp of an LED (light emitting diode) array type has been proposed. Figure 1 This is a block diagram of an ADB lamp of an LED array type. 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 for driving 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 current source to be turned on and off.

[0005] The power supply circuit 30 supplies a power supply voltage V to the LED array 10. DD The light distribution controller 20 generates a control signal that specifies the on / off of a plurality of pixels and sends it to the LED array 10. The light beam emitted by the LED array 10 is irradiated onto the virtual vertical screen 40 via an optical system (not shown). On the virtual vertical screen 40, a light distribution pattern 42 corresponding to the on / off of the plurality of light emitting elements 12 is formed.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-172038 Summary of the invention

[0009] Problem 1. If the light distribution pattern generation process in the light distribution controller 20 is handed over only to a microcomputer that performs software control, if the microcomputer fails to operate, the LED array 10 can no longer be controlled.

[0010] Problem 2. In a system where the resolution of the LED array 10 is low, a light distribution pattern can be generated using a general-purpose microcomputer.

[0011] However, if the resolution of the LED array 10 is increased (for example, higher than 100×100), it is not possible to increase the processing in a general-purpose microcomputer, and the architecture of a low-resolution system cannot be directly converted to another.

[0012] The present disclosure is made in view of the relevant situation, and one of the exemplary purposes of one solution is to provide a lighting system and a light distribution controller that improve functional safety. In addition, one of the exemplary purposes of other solutions is to provide a light distribution controller that can generate a high-resolution light distribution pattern.

[0013] Methods used to solve technical problems

[0014] 1. One aspect of the present disclosure relates to a light distribution controller for controlling a variable light distribution lamp including a plurality of pixels arranged in an array. The light distribution controller includes: a memory; a processor, which generates at least one image that specifies the light distribution of the variable light distribution lamp by executing a software program and writes the image into the memory; an abnormality detector, which detects an abnormality of the processor; and a hardware logic circuit, which (i) generates light distribution image data to be output to the variable light distribution lamp based on the at least one image written into 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.

[0015] 2. One solution of the present disclosure relates to a light distribution controller for controlling 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, which, by executing a software program, is capable of writing a first layer image specifying a light distribution of a high beam into the first area of ​​the memory, writing a second layer image specifying a light shielding portion of the high beam into the second area of ​​the memory, and writing a third layer image specifying a light distribution of a low beam into the third area of ​​the memory; and a hardware logic circuit, which reads the first layer image to the third layer image stored in the memory, and synthesizes the first layer image to the third layer image to generate light distribution image data.

[0016] Furthermore, any combination of the above-described constituent elements or any form of conversion of constituent elements or expressions of the present disclosure into methods, apparatuses, systems, etc. may also be practiced as additional forms of the present disclosure.

[0017] Effects of the Invention

[0018] According to one aspect of the present disclosure, a high-resolution light distribution pattern can be generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a block diagram of an ADB lamp using an LED array.

[0020] Figure 2 is a block diagram of a lighting system according to an embodiment.

[0021] Figure 3 It is a block diagram showing the structure of the light distribution controller.

[0022] Figure 4 Yes Description Figure 3 Diagram of the working of the light distribution controller.

[0023] Figure 5 This is a diagram for explaining alpha blending or multi-layer synthesis processing based on additive synthesis.

[0024] Figure 6 (a) and (b) are diagrams illustrating the generation of the third layer image.

[0025] Figure 7 It is a diagram for explaining the light distribution control of the high beam.

[0026] Figure 8 It shows that Figure 2 Diagram of a lighting system for a headlamp.

[0027] Fig. 9 This is a block diagram related to the functional safety of the light distribution controller.

[0028] Fig.10 This is a flowchart for explaining the operation of the hardware logic circuit of the first embodiment.

[0029] Fig.11 This is a flowchart illustrating the operation of the hardware logic circuit of the second embodiment.

[0030] Fig.12 This is a flowchart illustrating the operation of the hardware logic circuit of the third embodiment.

[0031] Fig.13 (a) is a diagram showing an ideal low beam light distribution pattern PTN_LO, Fig.13 (b) and (c) are diagrams showing examples of the auxiliary image IMG_AUX. DETAILED DESCRIPTION

[0032] (Overview of Embodiments)

[0033] An overview of several exemplary embodiments of the present disclosure is provided. This overview serves as a preface to the detailed description that will be described later. It is intended to provide a basic understanding of the embodiments and briefly describes several concepts of one or more embodiments. It is not intended to limit the scope of the invention or disclosure. This overview is not a general overview of all conceivable embodiments, and is not intended to identify the important elements of all embodiments or to define the scope of some or all schemes. For convenience, "one embodiment" is sometimes used to refer to one embodiment (an embodiment or a variation) or multiple embodiments (an embodiment or a variation) disclosed in this specification.

[0034] A light distribution controller of one embodiment controls a light distribution variable lamp including a plurality of pixels arranged in an array. The light distribution controller includes: a memory; a processor, which generates at least one image that specifies the light distribution of the light distribution variable lamp by executing a software program and writes the image into the memory; an abnormality detector, which detects an abnormality of the processor; and a hardware logic circuit, which (i) generates light distribution image data to be output to the light distribution variable lamp based on at least one image written in 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.

[0035] The light distribution controller can generate or obtain an auxiliary image for specifying a simple light distribution without using the processor when the processor is in an abnormal state. Therefore, when the processor is in an abnormal state, light distribution image data can be generated based on the auxiliary image, and the light distribution variable lamp can be kept on.

[0036] In one embodiment, the at least one image generated by the processor may include a high beam image that specifies the light distribution of the high beam, and a low beam image that specifies the light distribution of the low beam. The hardware logic circuit may also synthesize the high beam image and the low beam image to generate the light distribution image data in a normal state of the processor.

[0037] In one embodiment, when the processor is in an abnormal state, 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.

[0038] According to this configuration, when an abnormality occurs in the processor, the hardware logic circuit writes an auxiliary image that specifies a simple low-beam light distribution to the memory, and then generates light distribution image data based on the auxiliary image written by itself, thereby maintaining the low-beam lighting of the light distribution variable lamp.

[0039] In one embodiment, in an abnormal state of the processor, the hardware logic circuit may not write the auxiliary image into the memory, but directly output it as the light distribution image data. By reducing memory access, the heat generation of the memory can be reduced. In the case where 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.

[0040] In one embodiment, the abnormality detector may be configured to detect an abnormality of the memory. When the memory is in an abnormal state, the hardware logic circuit may not write the auxiliary image into the memory, but directly output it as the light distribution image data. Thus, even when the memory is in an abnormal state, the light distribution variable lamp can be kept on.

[0041] In one embodiment, the auxiliary image may have a pixel value of 0 in an area above a horizontal line passing through an inflection point of low-beam distribution and a non-zero pixel value in an area below the horizontal line. By making the auxiliary image a simple structure, the structure of the hardware logic circuit can be simplified.

[0042] In one embodiment, the pixel values ​​of the lower region of the auxiliary image may gradually change in the vertical direction. This can alleviate the sharp brightness difference near the cut-off line and form a light distribution that is easy for the driver to see.

[0043] In one embodiment, the pixel values ​​of the lower region of the auxiliary image may be uniform, thereby further simplifying the configuration of the hardware logic circuit.

[0044] In one embodiment, the pixel value of the area below the auxiliary image may be the minimum value of the upper limit value specified for each position in the low beam area, thereby preventing glare when pitching or avoiding the situation where the near side is too bright and the far side is difficult to see.

[0045] The abnormality detector may also be a microcomputer. Alternatively, when the microcomputer detects an abnormality, it receives an on / off instruction of the low beam from the upper controller and controls the hardware logic circuit.

[0046] The processor may also write a light shielding image that specifies the light shielding portion of the high beam into the memory. The hardware logic circuit may also generate light distribution image data based on the high beam image, the low beam image, and the light shielding image.

[0047] The vehicle lighting system according to one embodiment may also include: a light distribution controller; and a light distribution variable lamp controlled according to a light distribution pattern generated by the light distribution controller.

[0048] A light distribution controller of one embodiment controls a light distribution variable 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, which can write a first layer image specifying a light distribution of a high beam into the first area of ​​the memory, write a second layer image specifying a light shielding portion of the high beam into the second area of ​​the memory, and write a third layer image specifying a light distribution of a low beam into the third area of ​​the memory by executing a software program; and a hardware logic circuit, which reads out the first layer image to the third layer image stored in the memory, and synthesizes the first layer image to the third layer image to generate light distribution image data.

[0049] In this structure, the processor performs pre-processing to generate the third layer image from the first layer image of the high beam, the light shielding part of the high beam, and the low beam, and the hardware logic circuit performs post-processing to synthesize the first layer image to the third layer image. This reduces the load on the processor and can generate a high-resolution light distribution pattern.

[0050] Each pixel of the second layer image may also include an alpha value indicating the transparency of the image corresponding to the first layer image. The hardware logic circuit may also synthesize the first layer image and the third layer image according to the alpha value of the second layer image. In the synthesis, alpha blending or additive synthesis may be used.

[0051] The alpha value of the second layer image may also change gradually at the boundary of the light-shielded portion, thereby suppressing a sharp change in brightness at the boundary of the light-shielded portion and reducing discomfort.

[0052] The processor may also generate a third layer image based on a reference image that is a basis for the low beam light distribution. By generating a reference image in advance and processing and correcting it to generate the third layer image, the amount of computation by the processor can be reduced compared to generating the third layer image from scratch each time.

[0053] The reference image can cover the illumination range of the low beam, that is, cover an area wider than the illumination range of the variable light distribution lamp. The processor crops a part of the reference image to generate a third layer image.

[0054] The reference image covers a wider area than the illumination range of the low beam at least in the horizontal direction, and the processor can also achieve electronic rotation by changing the cropping position of the reference image in the horizontal direction.

[0055] The reference image covers a wider area than the illumination range of the low beam at least in the vertical direction, and the processor can also achieve leveling adjustment by changing the cropping position of the reference image in the vertical direction.

[0056] The light distribution controller may further include a non-volatile memory for storing the reference image.

[0057] The memory may also include a fourth area. The processor may also write a fourth layer image that specifies the light distribution of the high beam into the fourth area of ​​the memory. The hardware logic circuit may also synthesize the first layer image to the fourth layer image stored in the memory to generate light distribution image data. There are situations where you want to change the light distribution of the high beam in response to various driving scenarios. In this case, the light distribution that does not depend on the basis of the driving scene is defined as the first layer image, and the light distribution that depends on the adaptability of the driving scene is defined as the fourth layer image. By synthesizing them, a light distribution suitable for various driving scenes can be generated. Compared to the situation where a separate light distribution (first layer image) is prepared for each driving scene, the memory capacity can be reduced.

[0058] The processor may also generate a pattern depicted on the fourth layer of images by scaling the pattern depicted on the first layer of images. For example, the fourth layer of images may be generated by horizontally scaling down the first layer of images and synthesized with the original first layer of images. Thus, a light distribution suitable for high-speed driving may be formed.

[0059] (Implementation Method)

[0060] Below, the preferred embodiments are described with reference to the accompanying drawings. The same or equivalent components, parts, and processes shown in the drawings are marked with the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the embodiments are not intended to limit the disclosure or invention but are illustrative, and not all features or combinations described in the embodiments are essential parts of the disclosure or invention.

[0061] In this specification, the so-called "the state in which component A is connected to component B" includes the situation where component A and component B are physically directly connected, and also includes the situation where component A and component B are indirectly connected via other components that have no substantial impact on their electrical connection state or do not impair the function or effect achieved by their coupling.

[0062] Similarly, the so-called "state in which component C is arranged between component A and component B" means, in addition to the case of directly connecting component A and component C, or directly connecting component B and component C, it also includes the case of indirect connection via other components without substantially affecting their electrical connection state or damaging the function or effect achieved by their coupling.

[0063] Figure 2 1 is a block diagram of a lamp system 100 according to an embodiment. The lamp system 100 is an ADB lamp, and includes a host controller 102 , a variable light distribution lamp 200 , and a light distribution controller 300 .

[0064] 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 light-emitting pixel PIX can be switched on (lit) or off (extinguished) individually. The light-emitting pixel PIX can include, for example, a semiconductor light-emitting element such as an LED, and a current source that supplies a driving current to the semiconductor light-emitting element.

[0065] The outgoing light beam of the LED array device 210 is irradiated on the virtual vertical screen 40 via an optical system not shown. A light distribution pattern 42 corresponding to the on and off of a plurality of 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 outgoing light beam of the LED array device 210 covers the irradiation area of ​​the high beam and the irradiation area of ​​the low beam.

[0066] The interface circuit 220 receives light distribution image data IMG_LD defining the light distribution pattern 42 from the light distribution controller 300. The interface circuit 220 controls the on / off of each pixel of the LED array device 210 based on the light distribution image data IMG_LD.

[0067] PWM control is used in the grayscale expression of the brightness of the light-emitting pixel PIX of the LED array device 210. Each pixel of the light distribution image data IMG_LD can also represent the brightness value (grayscale value) of the light-emitting pixel PIX. The interface circuit 220 can generate a PWM signal with a duty factor corresponding to the pixel value for each pixel of the light distribution image data IMG_LD, and control the corresponding light-emitting pixel PIX to be turned on or off. That is, the interface circuit 220 has the function of a PWM controller.

[0068] The light distribution controller 300 supplies the information INFO necessary for generating the light distribution pattern 42 in addition to the lighting command CMD from the upper controller 102. The upper controller 102 may be an ECU (Electronic Control Unit) on the vehicle side or an ECU on the lamp side. More specifically, the lighting command CMD instructing the turning on and off of the low beam or high beam is input from the upper controller 102 to the light distribution controller 300.

[0069] In addition, the information INFO provided by the upper controller 102 to the light distribution controller 300 may include surrounding environment information or vehicle information. The surrounding environment information may include: (i) information related to objects such as the preceding vehicle or oncoming vehicle, pedestrians or signs, road markings, etc.; (ii) road information (information on the distinction between expressways, ordinary roads, suburbs, urban areas, etc., straight roads or curved roads, etc.); (iii) information on weather, good visibility, road surface conditions, etc. The vehicle information may include vehicle speed, steering angle, vehicle tilt angle, etc.

[0070] Figure 3 3 is a block diagram showing the structure of the light distribution controller 300. The vehicle bus interface 302 is a CAN (Controller Area Network) or a LIN (Local Interconnect Network), etc., and is provided for communication with the host controller 102 or other devices.

[0071] The light distribution controller 300 generates light distribution image data IMG_LD defining the light distribution pattern 42 based on the information INFO from the host controller 102, and transmits the data to the variable light distribution lamp 200. The light distribution controller 300 and the variable light distribution lamp 200 are connected via a video serial interface represented by HDMI (High-Definition Multimedia Interface, a registered trademark).

[0072] When a larger volume of data is to be transmitted between the host controller 102 and other devices, a broadband interface 304 may be provided. The broadband interface 304 may use Ethernet (registered trademark) or the like.

[0073] 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 other video interface.

[0074] 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 also be a SOC (System-on-a-chip). The oscillator 308 generates a clock signal and supplies it to the processor 312 and the hardware logic circuit 314. The processor 312 or the hardware logic circuit 314 operates in synchronization with the clock signal.

[0075] The processor 312 receives the lighting command CMD or the information IMFO via the vehicle bus interface 302 or the broadband interface 304 .

[0076] The nonvolatile memory 320 is a flash memory, a ROM (Read Only Memory), a ferroelectric memory, or a magnetoresistive RAM, and stores a software program to be executed by the processor 312. The processor 312 executes the program downloaded from the nonvolatile memory 320 and performs a part of the process for generating the light distribution image data IMG_LD.

[0077] The volatile memory 322 is used by the signal processing unit 310 to store software programs downloaded from the processor 312. In addition, it is also used as a video memory for storing images or data necessary for generating the light distribution image data IMG_LD. The volatile memory 322 is a RAM (Random Access Memory) such as a DRAM (Dynamic RAM) or an SDRAM (Synchronous DRAM). The volatile memory 322 includes a video storage area, and the video memory area includes a first area A1 to a third area A3.

[0078] By executing a software program, the processor 312 writes the first layer image L1 specifying the light distribution of the high beam into the first area A1 of the volatile memory 322, writes the second layer image L2 specifying the light-shielding part of the high beam into the second area A2 of the volatile memory 322, and writes the third layer image L3 specifying the light distribution of the low beam into the third area A3 of the volatile memory 322.

[0079] The hardware logic circuit 314 is a programmable logic device that allows designers to define and change logic circuits. The hardware logic circuit 314 reads 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, synthesizes the first layer image L1 to the third layer image L3, and generates light distribution image data IMG_LD.

[0080] Alternatively, the hardware logic circuit 314 may be formed of an ASIC (Application Specific Integrated Circuit).

[0081] The monitoring microcomputer 324 monitors the operating status of each functional block of the light distribution controller 300 and determines whether there is any abnormality. When 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 sends an error signal ERR to the host controller 102 via the vehicle bus interface 302.

[0082] The above is the structure of the light distribution controller 300. Next, the operation of the light distribution controller 300 will be described. Figure 4Yes Description Figure 3 FIG. 3 is a diagram showing the operation of the light distribution controller 300 . Figure 5 The diagram is for explaining a multi-layer synthesis process based on alpha blending or additive synthesis. The first layer image L1 to the third layer image L3 are image data having the same resolution as the LED array device 210 of the variable light distribution lamp 200 .

[0083] The first layer image L1 specifies the light distribution pattern PTN_HI of the high beam. The second layer image L2 specifies the light shielding portion SHD of the high beam. The third layer image L3 specifies the light distribution pattern PTN_LO of the low beam. These images are generated by the processor 312 executing a software program and written into 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 brightness value (duty factor in PWM control) of the corresponding light emitting element 212.

[0084] The hardware logic circuit 314 synthesizes the layer images L1 to L3 written in the first area A1 to the third area A3 to generate light distribution image data IMG_LD. Several examples of the image synthesis process will be described.

[0085] (First embodiment)

[0086] The second layer image L2 defining the light-shielding portion SHD is most simply 1-bit black-and-white image data, where a value of 0 corresponds to light shielding and a value of 1 corresponds to illumination. The pixel value inside the light-shielding portion SHD is 0, and the pixel value outside is 1.

[0087] At this time, the hardware logic circuit 314 can generate the light distribution image data IMD_LD according to the following calculation formula (1) for the values ​​of the pixels corresponding to the first layer image L1 to the third layer image L3.

[0088] IMD_LD[x, y]=L1[x, y]×L2[x, y]+L3[x, y]…(1)

[0089] Li[x, y] represents the pixel value at the position [x, y] of the i-th layer image. Through this calculation, the light shielding portion SHD has no influence on the light distribution of the low beam.

[0090] (Second embodiment)

[0091] In the first embodiment, at the boundary of the shading part SHD, the difference between light and dark becomes larger, so there is a situation that it is difficult for the driver to see. Therefore, the second layer image L2 can be set to multi-bit (m-bit) image data, and image synthesis can be performed according to the alpha blending method. At this time, each pixel value L2[x, y] of the second layer image L2 represents the alpha value. If it is set to m=8, the pixel whose pixel value L2[x, y] of the shading part is 0 is completely shading, and as the pixel value increases, the degree of shading decreases. Alpha blending is expressed by the following formula (2).

[0092] IMD_LD[x, y]=(L1[x, y]-L3[x, y])×(L2[x, y] / (2 m -1))+L3[x,y]…(2)

[0093] According to this method, by gradually changing the pixel value of the second layer image L2 at the boundary of the light shielding portion SHD, the difference in brightness at the boundary can be suppressed.

[0094] (Third Embodiment)

[0095] In the third embodiment, similarly to the second embodiment, the second layer image L2 represents an alpha value, but in the calculation, the additive synthesis represented by equation (3) is used.

[0096] IMD_LD[x, y]=L1[x, y]×(L2[x, y] / (2 m -1))+L3[x,y]…(3)

[0097] exist Figure 4 , Figure 5 In the example of , a case where both high beam and low beam are irradiated simultaneously is shown, but when only low beam is irradiated, the pixel value of the first layer image L1 can be set to 0. In addition, when there is no preceding vehicle or oncoming vehicle, the total pixel value of the second layer image L2 can be set to 255.

[0098] The above is the operation of the light distribution controller 300. According to the light distribution controller 300, the processor 312 performs preprocessing under software control, and the preprocessing separately generates the first layer image L1, the second layer image L2, and the third layer image L3 for specifying the high beam, the light shielding part of the high beam, and the low beam, and the hardware logic circuit 314 performs post-processing for synthesizing the first layer image L1 to the third layer image L3. In this way, the load of the processor 312 can be reduced, and a high-resolution light distribution pattern can be generated. In addition, by decomposing the elements of the light distribution image data into three layer images L1 to L3, various changes and applications can be made as described later.

[0099] Furthermore, the high beam light distribution is expressed by two layers, the first layer image L1 and the second layer image L2 . When only the light shielding portion is moved, only the second layer image L2 needs to be updated and the first layer image L1 does not need to be updated. This can reduce the load on the processor 312 .

[0100] Next, the generation process of the third layer image L3 will be described. Figure 6 (a) and (b) are diagrams illustrating the generation of the third layer image. Figure 6 (a) of FIG. 1 shows a reference image IMG_REF that defines a light distribution that is a basis for low beam. Figure 6 The reference image IMG_REF shown in (a) is an image that specifies the Z-type light distribution of the low beam. The 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 illumination range of the low beam. The reference image IMG_REF can also be stored in Figure 3 Alternatively, when the light distribution controller 300 is started, the processor 312 may draw the image according to the software program and store the image in the volatile memory 322. The processor 312 cuts a part of the reference image IMG_REF to generate the third layer image L3.

[0101] exist Figure 6 (b) shows the third layer image L3 when the horizontal ranges H1 and H2 are cut. According to this method, the amount of calculation processing required by the processor 312 for rendering the third layer image L3 can be greatly reduced.

[0102] For example, the processor 312 may determine the cropping range based on the steering angle or road information (straight road or curved road, etc.) included in the vehicle information from the host controller 102. In this way, the electronic rotation function can be realized.

[0103] Similarly, the reference image IMG_REF may also cover a wider area than the illumination range of the low beam in the vertical direction. The processor 312 may implement leveling adjustment by changing the cropping position of the reference image IMG_REF in the vertical direction.

[0104] Next, the control of high beam distribution is described. When driving on a highway, it is sometimes necessary to form a distribution with a bright illumination area concentrated in the central part. If multiple reference images for high beam are prepared for each driving scene, the capacity of the non-volatile memory will increase, which will cause cost increase.

[0105] Therefore, in order to switch the light distribution of the high beam according to the driving scene, the following processing may be performed. Figure 73 is a diagram for explaining the light distribution control of the high beam. In order to switch or control the light distribution of the high beam, 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.

[0106] The processor 312 writes the fourth layer image L4 that specifies the high beam light distribution into the fourth area A4. The fourth layer image L4 represents the pattern PTN_HI_ADD of the high beam light distribution that is added to the first layer image L1 as the basis, and from another point of view, it can be understood as the difference between the high beam light distribution corresponding to the driving scene and the high beam light distribution as the basis.

[0107] The hardware logic circuit 314 synthesizes the first layer image L1 to the fourth layer image L4 to generate the light distribution image data IMG_LD. At this time, the second layer image L2 acts on both the first layer image L1 and the fourth layer image L4. When the third layer image L3 is 1 bit, the synthesis according to equation (1') can be performed.

[0108] IMD_LD[x, y]=(L1[x, y]+L4[x, y])×L2[x, y]+L3[x, y]…(1')

[0109] When the third layer image L3 indicates an alpha value, synthesis based on equation (2') or (3') can be performed.

[0110] IMD_LD[x, y]=(L1[x, y]+L4[x, y]-L3[x, y])×(L2[x, y] / (2 m -1))+L3[x,y]…(2')

[0111] IMD_LD[x, y]=(L1[x, y]+L4[x, y])×(L2[x, y] / (2 m -1))+L3[x,y]…(3')

[0112] According to this method, by switching the fourth layer image L4 according to the driving scene, it is possible to generate light distribution suitable for various driving scenes.

[0113] The addition pattern PTN_HI_ADD depicted in the fourth layer image L4 may also be stored in the nonvolatile memory 320 .

[0114] Alternatively, the addition pattern PTN_HI_ADD drawn on the fourth layer image L4 may be generated by scaling the pattern PTN_HI drawn on the first layer image L1. Figure 7In the example of , the addition pattern PTN_HI_ADD is generated by compressing the pattern PTN_HI in the lateral direction. Therefore, since it is not necessary to store the addition pattern PTN_HI_ADD in the nonvolatile memory 320, an increase in the capacity of the nonvolatile memory 320 can be suppressed.

[0115] The drawing position of the addition pattern PTN_HI_ADD may be shifted in accordance with the turning or cornering situation.

[0116] (Variant 1)

[0117] The structure of the variable light distribution lamp 200, which is the object of control of 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 light 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) or a liquid crystal panel.

[0118] (Variant 2)

[0119] The method of transmitting the light distribution image data IMG_LD from the light distribution controller 300 to the light distribution variable lamp 200 is not particularly limited. n Grayscale), the light distribution image data IMG_LD can be decomposed into two n 1-bit subframe and transmit it. n Each pixel of the subframe takes 1 or 0, and the appearance ratio of the value 1 and 0 (i.e., the duty cycle) changes according to the pixel value corresponding to the light distribution image data IMG_LD. The light distribution variable lamp 200 sets the pixel corresponding to the LED array device 210 to be turned on when the value is 1 for each pixel of the subframe, and sets the pixel corresponding to the LED array device 210 to be turned off when the value is 0. That is, the light distribution controller 300 has the function of a PWM controller.

[0120] Figure 8 It shows that Figure 2FIG. 1 is a diagram of a headlamp 600 of a lighting system 100. The headlamp 600 includes a variable light distribution lamp 200 and an image sensor 500. The light distribution (especially the light-shielded portion, i.e., the second layer image L2) to be generated by the variable light distribution lamp 200 can be generated based on the image captured by the image sensor 500. The light distribution controller 300 can be accommodated in a housing 602 of the headlamp 600, or can be arranged outside the housing 602. In addition, the headlamp 600 also includes a turn signal 606 and a position signal 608. Due to the limitation of the illumination area that the LED array device 210 can cover, in the case where it is difficult to generate a complete low beam light distribution only by the LED array device 210, an auxiliary low beam light source 604 can be added to illuminate a wider range of areas.

[0121] (Functional Safety)

[0122] Next, functional safety in the light distribution controller 300 will be described.

[0123] Fig. 9 This is a block diagram related to the functional safety of the light distribution controller. The basic structure of the light distribution controller 300A is shown in Figure 3 Description.

[0124] The processor 312 generates at least one image that specifies the light distribution of the variable light distribution lamp 200 by executing the software program, and writes it into the volatile memory 322. In this embodiment, the image generated by the processor 312 includes a high-beam image that specifies the light distribution of the high beam, and a low-beam image that specifies the light distribution of the low beam. The high-beam image IMG_HI may correspond to the first layer image L1, the second layer image L2 (and the fourth layer image L4) in the above description, and the low-beam image IMG_LO may correspond to the third layer image L3.

[0125] In the normal state of the processor 312, the hardware logic circuit 314 generates the light distribution image data IMG_LD according to the high beam image IMG_HI and the low beam image IMG_LO written in 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 the light distribution image data IMG_LD.

[0126] In order to achieve the functional safety effect described here, the layer structure is not limited to Figure 4 or Figure 7 In the illustrated case, at least the image describing the high beam and the image describing the low beam may be separately written into different areas of the volatile memory 322 .

[0127] In one example, if Figure 4 or Figure 7As shown, the processor 312 can write three (or four) layer images L1 to L3 (L4) as the high beam image IMG_HI and the low beam image IMG_LO into the volatile memory 322. At this time, the synthesis processing unit 316 is configured to synthesize the plurality of layer images according to the above-mentioned calculation formula.

[0128] In other examples, the processor 312 may generate a high-beam image IMG_HI that passes through the light-shielded portion and write it together with the low-beam image IMG_LO into the volatile memory 322. That is, the processor 312 may perform a synthesis process of the first layer image L1 and the second layer image L2. At this time, the synthesis processing unit 316 synthesizes the high-beam image IMG_HI and the low-beam image IMG_LO to generate the light distribution image data IMG_LD.

[0129] IMG_LD[x, y]=IMG_HI[x, y]+IMG_LO[x, y]

[0130] The monitoring microcomputer 324 is an abnormality detector capable of detecting an abnormality of the processor 312. When the processor 312 is normal, the processor 312 receives a low beam or high beam lighting command CMD from the host controller 102, but when the processor 312 is abnormal, the processor 312 can receive a control signal CNT corresponding to the lighting command CMD from the host controller 102. The control signal CNT can be received via the vehicle bus interface 302 or via a straight line (connecting line) not shown.

[0131] When the monitoring microcomputer 324 detects an abnormality in the processor 312, the operation of the processor 312 stops. The method of detecting the abnormality is not particularly limited, and a method using a timer or the like can be used by using a known technique. When the monitoring microcomputer 324 detects an abnormality in the processor 312, it notifies the hardware logic circuit 314.

[0132] The auxiliary image development unit 318 of the hardware logic circuit 314 is configured to generate or acquire the auxiliary image IMG_AUX independently of 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.

[0133] When the hardware logic circuit 314 is a programmable logic circuit, the auxiliary image development unit 318 may include a pattern generator composed of a combination of a counter and a logic gate. The auxiliary image IMG_AUX is preferably close to the normal low beam distribution, but due to the limitations of the available hardware, the low beam distribution may actually be simplified hardware.

[0134] The above is the structure of the light distribution controller 300A. The light distribution controller 300A can generate or obtain the auxiliary image IMG_AUX that specifies a simple light distribution without using the processor 312 when the processor 312 is in an abnormal state. Therefore, when the processor 312 is in an abnormal state, the light distribution image data IMG_LD can be generated based on the auxiliary image IMG_AUX, and the light distribution variable lamp 200 can be kept on.

[0135] Next, several examples related to the operation of the light distribution controller 300A in an abnormal state will be described.

[0136] (Example 1)

[0137] 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.

[0138] 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.

[0139] In an abnormal state, the synthesis processing unit 316 directly outputs the auxiliary image IMG_AUX read from the volatile memory 322 as the light distribution image data IMG_LD.

[0140] Fig.10 1 is a flowchart for explaining the operation of the hardware logic circuit 314 of the first embodiment. In the normal state of the processor 312 (Y in S100), the hardware logic circuit 314 synthesizes the high beam image IMG_HI and the low beam image IMG_LO of the processor 312 to generate the light distribution image data IMG_LD (S102). The light distribution image data IMG_LD is output to the light distribution variable lamp 200 (S104).

[0141] In the abnormal state of the processor 312 (N of S100), the monitoring microcomputer 324 determines whether the low beam switch is on (S106). When the low beam switch is off (N of S106), the process returns to S100. When the low beam switch is on (Y of S106), the hardware logic circuit 314 develops the auxiliary image IMGAUX in the volatile memory 322 (S108). Furthermore, the auxiliary image IMG_AUX read from the volatile memory 322 is set as the light distribution image data IMG_LD (S110).

[0142] Note that the development of the auxiliary image IMG_AUX onto the volatile memory 322 ( S108 ) only needs to be performed once, and the second and subsequent developments may be skipped.

[0143] (Example 2)

[0144] The auxiliary image development unit 318 writes the auxiliary image IMG_AUX into the volatile memory 322, deletes 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. Thus, the high beam image IMG_HI with a pixel value of 0 is synthesized with the auxiliary image IMG_AUX written instead of the low beam image IMG_LO, and the light distribution image data IMG_LD is the same as the auxiliary image IMG_AUX.

[0145] Fig.11 1 is a flowchart for explaining the operation of the hardware logic circuit 314 of the second embodiment. In the normal state of the processor 312 (Y in S200), the hardware logic circuit 314 synthesizes the high beam image IMG_HI and the low beam image IMG_LO of the processor 312 to generate the light distribution image data IMG_LD (S202). The light distribution image data IMG_LD is output to the light distribution variable lamp 200 (S204).

[0146] In the abnormal state of the processor 312 (N of S200), it is determined whether the low beam switch is on (S206). When the low beam switch is off (N of S206), it returns to S200. When the low beam switch is on (Y of S206), the hardware logic circuit 314 expands the auxiliary image IMG_AUX in the area of ​​the low beam image IMG_LO of the volatile memory 322 (S208). In addition, the area of ​​the high beam image IMG_HI of the volatile memory 322 is reset (S210). Moreover, the high beam image IMG_HI and the auxiliary image IMG_AUX read from the volatile memory 322 are synthesized to generate the light distribution image data IMG_LD (S212).

[0147] In addition, the processes S208 and S210 only need to be performed once, and can be skipped after the second time.

[0148] (Example 3)

[0149] When the processor 312 is in an abnormal state, the hardware logic circuit 314 does not write the auxiliary image IMG_AUX developed by the auxiliary image development unit 318 into the volatile memory 322 , but directly outputs the auxiliary image IMG_LD as the light distribution image data.

[0150] Fig.12 This is a flowchart for explaining the operation of the hardware logic circuit 314 of the third embodiment. In the normal state of the processor 312 (Y in S300), the hardware logic circuit 314 synthesizes 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 outputs it (S304).

[0151] In the third embodiment, since the volatile memory 322 is not used, the auxiliary image IMG_AUX cannot be stored. Therefore, in the abnormal state of the processor 312 (N of S300), when the low beam switch is on (Y of S306), the auxiliary image development unit 318 develops the auxiliary image IMG_AUX at the frame rate of each light distribution image data IMG_LD as the light distribution image data IMG_LD (S308). If the low beam switch is off (N of S306), the process returns to S300.

[0152] According to the third embodiment, access to the volatile memory 322 can be reduced, and the heat of the volatile memory 322 can be reduced. When the processor 312 is in an abnormal state due to high temperature, the processor 312 can be prevented from being heated by the volatile memory 322, and can be cooled in a short time, thereby being able to return to a normal state.

[0153] Furthermore, the control of the third embodiment is effective even when an abnormality occurs in the volatile memory 322. Fig.12 The “processor” in process S300 can be replaced by “volatile memory”.

[0154] The signal processing unit 310 can switch the control of the first to third embodiments according to the location or cause of the abnormality. For example, the control of the first or second embodiment can be performed when the processor 312 is in an abnormal state, and the control of the third embodiment can be performed when the volatile memory 322 is in an abnormal state.

[0155] Furthermore, when the processor 312 is abnormal and the volatile memory 322 is normal, and the temperature of the light distribution controller 300A is high, the control of the third embodiment may be performed.

[0156] Next, the auxiliary image IMG_AUX will be described. Fig.13 (a) is a diagram showing an ideal low beam light distribution pattern PTN_LO, Fig.13 (b) and (c) are diagrams showing examples of the auxiliary image IMG_AUX. Fig.13 The auxiliary image IMG_AUX1 of (b) is an image in which the light distribution of the low beam is thickened. Fig.13 The auxiliary image IMG_AUX1 of (b) is suitable for a case where there is a surplus in the hardware of the auxiliary image development unit 318 or a case where the hardware logic circuit 314 is constituted by an ASIC.

[0157] Auxiliary image IMG_AUX compared to Fig.13 (b) can be further simplified, Fig.13More specifically, the auxiliary image IMG_AUX2 has a pixel value of 0 in a region R1 above a horizontal line HL passing through the inflection point P of the low-beam light distribution pattern PTN_LO, and a pixel value of non-zero in a region R2 below. Fig.13 The auxiliary image IMG_AUX of (c) can be expanded on the volatile memory 322 by extremely simple hardware.

[0158] The pixel value of the area below the auxiliary image IMG_AUX2 can be set to be uniform. The pixel value at this time can be the minimum value of the upper limit value specified by the law according to the position of each low beam light distribution pattern PTN_LO. This can prevent glare when pitching and can also avoid the situation where the near side is too bright and it is difficult to see the far side.

[0159] Alternatively, the pixel values ​​of the lower region of the auxiliary image IMG_AUX2 may be gradually changed in the vertical direction. This can alleviate the sharp brightness difference near the cutoff line, and form a light distribution that is easy for the driver to see.

[0160] Next, modifications related to functional safety will be described.

[0161] (Variant 1)

[0162] In the case where the hardware logic circuit 314 can access the non-volatile memory 320 , the auxiliary image IMGAUX may be stored in the non-volatile memory 320 and read.

[0163] (Variant 2)

[0164] In the embodiment, the processor 312 generates the high beam image IMG_HI and the low beam image IMG_LO separately and synthesizes them in the hardware logic circuit 314, but the present invention is not limited thereto. The processor 312 may generate a piece of image data that specifies the final light distribution of the variable light distribution lamp 200 and write it into the volatile memory 322. At this time, the hardware logic circuit 314 reads the image data from the volatile memory 322 in a normal state and transfers it to the output interface 306 of the subsequent stage. In an abnormal state, the auxiliary image IMG_AUX is transferred to the output interface 306.

[0165] The embodiments merely illustrate the principles and applications of the present invention, and various modifications or changes in configuration are permitted to the embodiments without departing from the spirit of the present invention defined in the claims.

[0166] Industrial Applicability

[0167] The invention relates to a vehicle lamp.

[0168] Description of Reference Numerals

[0169] 100…lighting system, 102…upper controller, 300…light distribution controller, 200…light distribution variable lamp, 210…LED array device, 212…light emitting element, 220…interface circuit, 300…light distribution controller, 302…vehicle bus interface, 304…wideband 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 area, A2…second area, A3…third area.

Claims

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

2. The light distribution controller according to claim 1, characterized in that: Each pixel of the second layer image includes an alpha value indicating the transparency of the corresponding pixel of the first layer image, The hardware logic circuit synthesizes the first layer image and the third layer image according to the second layer image.

3. The light distribution controller according to claim 2, characterized in that: The alpha value of the second layer image changes gradually at the boundary of the light-shielded portion.

4. The light distribution controller according to claim 1, characterized in that: The processor generates the third layer image based on a reference image that defines a light distribution serving as a basis for the low beam.

5. The light distribution controller according to claim 4, characterized in that: The reference image covers a wider area than the illumination range of the low beam. The processor crops a portion of the reference image to generate the third layer image.

6. The light distribution controller according to claim 5, characterized in that: The reference image covers a wider area than the illumination range of the low beam at least in the horizontal direction. The processor realizes electronic rotation by changing the cropping position of the reference image in the horizontal direction.

7. The light distribution controller according to claim 5, characterized in that: The reference image covers a wider area than the illumination range of the low beam at least in the vertical direction. The processor implements leveling adjustment by changing a cropping position of the reference image in a vertical direction.

8. The light distribution controller according to any one of claims 4 to 7, characterized in that: Also included is a non-volatile memory storing the reference image.

9. The light distribution controller according to any one of claims 1 to 7, characterized in that: The memory further comprises a fourth area, The processor writes a fourth layer image that specifies the light distribution of the high beam into the fourth area of ​​the memory, The hardware logic circuit synthesizes the first layer image to the fourth layer image stored in the memory to generate the light distribution image data.

10. The light distribution controller according to claim 9, characterized in that: The processor generates the pattern depicted in the fourth layer image by scaling the pattern depicted in the first layer image.

11. A vehicle lighting system, characterized in that: include: The light distribution controller according to any one of claims 1 to 10; as well as A variable light distribution lamp is controlled based on the light distribution pattern generated by the light distribution controller.

12. A control method, characterized in that: A control method for a variable light distribution lamp including a plurality of pixels arranged in an array, comprising: The step of writing a first layer image specifying a high beam light distribution into a first area of ​​a memory; The step of writing a second layer image defining the light shielding portion of the high beam into a second area of ​​the memory; The step of writing a third layer image specifying the light distribution of the low beam into a third area of ​​the memory; A step of synthesizing the first layer image to the third layer image stored in the memory by a hardware logic circuit to generate light distribution image data; and The step of converting the pixel value of each pixel of the light distribution image data into a PWM signal to control the corresponding pixel.

Images