WO2022270415A1

WO2022270415A1 - Light distribution controller and vehicle light system

Info

Publication number: WO2022270415A1
Application number: PCT/JP2022/024219
Authority: WO
Inventors: 昌司加藤; 浩孝沢田
Original assignee: 株式会社小糸製作所
Priority date: 2021-06-22
Filing date: 2022-06-16
Publication date: 2022-12-29
Also published as: JPWO2022270415A1

Abstract

A drawing processing unit (310) generates multi-gradation light distribution image data (IMG_LD) defining light distribution. An interface circuit (320) converts the light distribution image data (IMG_LD) into a serial interface signal (SerIF) having a signal format required by a patterning device (200), and transmits the serial interface signal (SerIF) to a light distribution controller (300). A decoder (330) receives a feedback signal (FB) based on the serial interface signal (SerIF), and restores a PWM control signal (PWM_PIXz) with respect to a pixel of interest in the patterning device (200). An abnormality detector (340) determines, on the basis of the PWM control signal (PWM_PIXz) restored by the decoder (330), whether or not an abnormality is present.

Description

Light distribution controller and vehicle lighting system

The present invention relates to a vehicle lamp.

Vehicle lamps can generally be switched between low beam and high beam. The low beam illuminates the vicinity of the vehicle with a predetermined illuminance, and is used mainly when driving in an urban area. On the other hand, high beams illuminate a wide area ahead and far away with relatively high illuminance, and are mainly used when driving at high speed on roads with few oncoming or preceding vehicles. Therefore, although the high beam is superior in visibility to the driver compared to the low beam, there is a problem in that it gives glare to the driver of the vehicle and pedestrians present in front of the vehicle.

In recent years, ADB (Adaptive Driving Beam) has been proposed that dynamically and adaptively controls the high beam light distribution pattern based on the surrounding conditions of the vehicle. ADB technology detects the presence of preceding vehicles, oncoming vehicles, and pedestrians in front of the vehicle, and dims or extinguishes the area corresponding to the vehicle or pedestrian to reduce glare to the vehicle or pedestrian. It is a thing.

An LED (light emitting diode) array system has been proposed as an ADB lamp. 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 between on and off by controlling the on/off of the current source.

A power supply circuit 30 supplies a power supply voltage _VDD to the LED array 10 . The light distribution controller 20 generates a control signal designating ON/OFF of the plurality of pixels, and transmits the control signal to the LED array 10 . A beam emitted from the LED array 10 is irradiated onto the virtual vertical screen 40 through an optical system (not shown). A light distribution pattern 42 corresponding to ON/OFF of the plurality of light emitting elements 12 is formed on the virtual vertical screen 40 .

Japanese Patent Application Laid-Open No. 2018-172038

　In-vehicle parts, including vehicle lamps, require high reliability. In the case of the ADB lamp of FIG. 1, a function of detecting whether the correct light distribution pattern 42 is formed is required.

The present disclosure has been made in such a situation, and one exemplary purpose of certain aspects thereof is to provide a lighting system and a light distribution controller with more advanced anomaly detection capabilities.

A light distribution controller according to an aspect of the present disclosure controls a patterning device that includes a plurality of control elements arranged in an array. The light distribution controller is a rendering processing unit that generates multi-gradation light distribution image data that defines light distribution, and the pixel value of each pixel of the light distribution image data is used for PWM control of the corresponding control element of the patterning device. an interface circuit that converts light distribution image data into a serial interface signal having a signal format required by the patterning device and transmits the signal to the light distribution controller; a decoder that receives a feedback signal based on the patterning device and restores a PWM control signal for a pixel of interest in the patterning device; and an abnormality detector that determines whether there is an abnormality based on the PWM control signal restored by the decoder.

Arbitrary combinations of the above components, or conversions of the expressions of the present disclosure between methods, devices, etc. are also effective as aspects of the present invention.

According to an aspect of the present disclosure, it is possible to provide a highly functional malfunction of the lamp system.

1 is a block diagram of an LED array type ADB lamp; FIG. 1 is a block diagram of a lamp system according to an embodiment; FIG. 1 is a block diagram of a lighting system including a light distribution controller according to an embodiment; FIG. 3 is a block diagram showing a configuration example of an interface circuit; FIG. 3 is a diagram showing an example of light distribution image data IMG_LD, serial interface signal SerIF, and PWM control signal PWM_PIX; FIG. It is a block diagram which shows the structural example of an abnormality detector.

(Overview of embodiment)
SUMMARY OF THE INVENTION Several exemplary embodiments of the disclosure are summarized. This summary presents, in simplified form, some concepts of one or more embodiments, as a prelude to the more detailed description that is presented later, and for the purpose of a basic understanding of the embodiments. The size is not limited. This summary is not a comprehensive overview of all possible embodiments, and it is intended to neither identify key elements of all embodiments nor delineate the scope of some or all aspects. For convenience, "one embodiment" may be used to refer to one embodiment (example or variation) or multiple embodiments (examples or variations) disclosed herein.

A light distribution controller according to one embodiment controls a patterning device including a plurality of control elements arranged in an array. The light distribution controller is a rendering processing unit that generates multi-gradation light distribution image data that defines light distribution, and the pixel value of each pixel of the light distribution image data is used for PWM control of the corresponding control element of the patterning device. an interface circuit that converts light distribution image data into a serial interface signal having a signal format required by the patterning device and transmits the signal to the light distribution controller; a decoder that receives a feedback signal based on the patterning device and restores a PWM control signal for a pixel of interest in the patterning device; and an abnormality detector that determines whether there is an abnormality based on the PWM control signal restored by the decoder.

According to this configuration, the serial interface signal generated by the interface circuit is monitored, and an abnormality is detected according to the feedback signal based thereon. This makes it possible to detect not only anomalies caused by the drawing processing unit, but also anomalies caused by the interface circuit in the succeeding stage, enabling more advanced anomaly detection.

In one embodiment, the anomaly detector may measure at least one of the high section and low section of the PWM control signal using a time measurement unit (TMU). In this case, the presence or absence of abnormality can be determined by whether the measured time matches the expected value based on the original light distribution image data.

In one embodiment, the decoder may restore the PWM control signal with all pixels of the turning device as pixels of interest. By subjecting all pixels to abnormality detection, more advanced abnormality detection becomes possible.

In one embodiment, the light distribution image data may include n pixels. The interface circuit may include a pulse width modulator that generates n intermediate codes corresponding to n pixels, and a serializer that converts the n intermediate codes into the serial interface signal. The intermediate code may include m bits, and the number of 1's included in the j-th (1≤j≤n) intermediate code may correspond to the pixel value of the j-th pixel. The serial interface signal may include m slots, each slot including n bits, and the m bits forming the j-th intermediate code may be assigned to the j-th bit of the m slots.

In one embodiment, the intermediate code may be a thermometer code.

In one embodiment, the patterning device may be a micro LED.

(embodiment)
Preferred embodiments will be described below with reference to the drawings. The same or equivalent constituent elements, members, and processes shown in each drawing are denoted by the same reference numerals, and duplication of description will be omitted as appropriate. Moreover, the embodiments are illustrative rather than limiting of the disclosure and invention, and not all features or combinations thereof described in the embodiments are necessarily essential to the disclosure and invention. No.

In this specification, "a state in which member A is connected to member B" refers to a case in which member A and member B are physically directly connected, as well as a case in which member A and member B are electrically connected to each other. It also includes the case of being indirectly connected through other members that do not substantially affect the physical connection state or impair the functions and effects achieved by their combination.

Similarly, "the state in which member C is provided between member A and member B" refers to the case where member A and member C or member B and member C are directly connected, as well as the case where they are electrically connected. It also includes the case of being indirectly connected through other members that do not substantially affect the physical connection state or impair the functions and effects achieved by their combination.

FIG. 2 is a block diagram of the lamp system 100 according to the embodiment. The lamp system 100 is a variable light distribution lamp such as an ADB lamp or a road drawing lamp, and includes a host controller 102 , a patterning device 200 and a light distribution controller 300 .

The patterning device 200 comprises an LED array (also called micro-LEDs) 210 that functions as a spatial light modulator, and an interface circuit 220 . The LED array 210 includes an array of a plurality of n control elements (hereinafter referred to as luminescent pixels PIX), and each luminescent pixel PIX can be individually switched between on (lighting) and off (extinguishing). The light-emitting pixel PIX can include, for example, a semiconductor light-emitting element such as an LED, and a current source that supplies drive current to the semiconductor light-emitting element.

The beams emitted from the LED array 210 are irradiated onto the virtual vertical screen 40 through an optical system (not shown). A light distribution pattern 42 is formed on the virtual vertical screen 40 corresponding to the on/off state of the plurality of light emitting pixels PIX.

The interface circuit 220 includes a serial receiver. The interface circuit 220 is connected to the light distribution controller 300 via the serial signal line 202 . Patterning device 200 receives serial interface signal SerIF from light distribution controller 300 . This serial interface signal SerIF contains control information for the plurality of light emitting pixels PIX of the LED array 210 .

The interface circuit 220 controls the brightness of the plurality of light emitting pixels PIX1 to PIXn forming the LED array 210 in multiple gradations based on the serial interface signal SerIF.

The light distribution controller 300 controls the patterning device 200 to form the desired light distribution pattern 42 . Information INFO necessary for generating the light distribution pattern 42 is supplied to the light distribution controller 300 in addition to the lighting command CMD from the host controller 102 . The host controller 102 may be a vehicle-side ECU (Electronic Control Unit) or a lamp-side ECU. Specifically, the host controller 102 inputs to the light distribution controller 300 a lighting command CMD that instructs to turn on/off the low beam and high beam.

The information INFO that the host controller 102 supplies to the light distribution controller 300 may include ambient environment information and vehicle information. Surrounding environment information includes (i) information on preceding and oncoming vehicles, pedestrians, signs, targets such as delineators, and (ii) road information (expressway, general road, suburb, urban area, straight road or curved road). (iii) information such as weather, visibility, and road conditions. Vehicle information may include vehicle speed, steering angle, vehicle tilt angle, and the like.

The light distribution controller 300 determines a light distribution pattern based on vehicle information, and controls the patterning device 200 so that the determined light distribution pattern is obtained.

FIG. 3 is a block diagram of the lighting system 100 including the light distribution controller 300 according to the embodiment.

First, the patterning device 200 to be controlled by the light distribution controller 300 will be described.

The patterning device 200 comprises an LED array 210 and an interface circuit 220 . The light-emitting pixels PIX of the LED array 210 can be switched between two states of ON/OFF. The patterning device 200 expresses the brightness of each pixel in multiple gradations by changing the ON time (duty cycle) per cycle by PWM control.

The interface circuit 220 includes a serial receiver. The interface circuit 220 is connected to the light distribution controller 300 via the serial signal line 202 . Patterning device 200 receives serial interface signal SerIF from light distribution controller 300 . This serial interface signal SerIF contains luminance information of the plurality of light emitting pixels PIX of the LED array 210 .

The interface circuit 220 generates PWM control signals PWM_PIX1 to PWM_PIXn corresponding to the plurality of light emitting pixels PIX1 to PIXn based on the serial interface signal SerIF. The i-th light-emitting pixel PIXi is controlled to be turned on or off based on the corresponding PWM control signal PWM_PIXi.

Next, the configuration of the light distribution controller 300 will be described. The light distribution controller 300 includes a vehicle bus interface 302 , a drawing processor (drawing engine) 310 , an interface circuit 320 , a decoder 330 and an abnormality detector 340 .

The vehicle bus interface 302 is CAN (Controller Area Network), LIN (Local Interconnect Network), etc., and is provided for communication with the host controller 102 and other devices.

The light distribution controller 300 generates light distribution image data IMG_LD that defines the light distribution pattern 42 based on the information INFO from the upper controller 102 , converts it into a serial interface signal SerIF, and transmits it to the patterning device 200 . Light distribution controller 300 and patterning device 200 are connected via a serial signal line 202 .

The drawing processing unit 310 generates multi-gradation light distribution image data IMG_LD that defines the light distribution of the variable light distribution lamp. Each pixel of the light distribution image data IMG_LD defines the brightness of the corresponding portion of the light distribution pattern 42 . Gradation control of the patterning device 200 is based on PWM control, and each pixel of the LED array 210 is PWM-controlled based on the PWM control signal PIX_PWM. Therefore, it can be said that each pixel of the light distribution image data IMG_LD defines the duty cycle, that is, the pulse width of the PWM control signal PIX_PWM for the corresponding light-emitting pixel PIX of the LED array 210 .

The drawing processing unit 310 may include a processor and hardware logic circuits. The drawing processing unit 310 may be an SOC (System-on-a-chip).

The interface circuit 320 converts the light distribution image data IMG_LD into a serial interface signal SerIF having a signal format required by the interface circuit 220 of the patterning device 200 .

The decoder 330 receives a feedback signal FB based on the serial interface signal SerIF. The decoder 330 restores the PWM control signal PWM_PIXz for the target pixel PIXz in the patterning device 200 based on the feedback signal FB. The restored PWM control signal PWM_PIXz is denoted as PWM_PIXz'. The anomaly detector 340 determines whether there is an anomaly based on the PWM control signal PWM_PIXz' restored by the decoder 330 . Although the number of target pixels is not limited, it is preferable to perform abnormality detection using all pixels as target pixels.

The feedback signal FB may be taken from the middle (i) of the serial signal line 202, as shown in FIG. (iii) may be taken out.

FIG. 4 is a block diagram showing a configuration example (320A) of the interface circuit 320. As shown in FIG. Interface circuit 320A includes pulse width modulator 322 and serializer 324 . The pulse width modulator 322 generates n intermediate codes MC1-MCn corresponding to the n pixels p1-pn of the light distribution image data IMG_LD. The intermediate code MC includes m bits, and the number of 1's included in the j-th (1≤j≤n) intermediate code MCj corresponds to the pixel value of the j-th pixel pj. For example, when the pixel value of pixel pj is 3, intermediate code MCj includes three 1's and (m-3) 0's.

When the PWM frequency is M times (M≧1) the update rate of the light distribution image data IMG_LD, the n intermediate codes MC1 to MCn are set M times for one light distribution image data IMG_LD, Generated repeatedly.

For example, the pulse width modulator 322 generates a triangular wave (ramp wave, sawtooth wave) having a PWM frequency, compares the triangular wave with the pixel value pj, and converts it into a binary signal. The intermediate code MCj may be generated by dividing this binary signal into m parts within one PWM period.

The serializer 324 converts the n intermediate codes MC1 to MCn into a serial interface signal SerIF.

The configuration of the lamp system 100 is as described above. Next, the operation will be explained.

FIG. 5 is a diagram showing an example of the light distribution image data IMG_LD, the serial interface signal SerIF, and the PWM control signal PWM_PIX.

Here, to simplify the explanation and facilitate understanding, it is assumed that the number of pixels in the light distribution image data IMG_LD, that is, the number n of light emitting pixels of the LED array 210 is four. Let the four pixels be p1 to p4. It is also assumed that the pixel values of the plurality of pixels p1 to p4 of the light distribution image data IMG_LD change in (m+1) gradations. In this example, m=8 and the pixel values can be 9 gradations from 0 to 8. Specifically, it is assumed that the pixel values of the four pixels p1 to p4 of the light distribution image data IMG_LD are 4, 3, 6, and 2, respectively.

The serial interface signal SerIF includes m time slots TS1 to TSm. Each time slot contains n bits. Each pixel of the light distribution image data IMG_LD is assigned to a corresponding one of the n bits in each of the plurality of time slots. For example, the first pixel p1 is assigned to the leftmost bit of time slot TS, the second pixel p2 to the second bit from the left, and the jth pixel pj to the jth from the left.

An intermediate code MCj representing the pixel value of pixel pj is stored in the j-th bit of m time slots TS1 to TSm. The intermediate code MCj is preferably a right-justified or left-justified thermometer code. For example, when the pixel value of pixel pj is 4, the left-justified thermometer code is MCj=[11110000], and when the pixel value of pixel pj is 7, the left-justified thermometer code is MCj=[11111110]. becomes. Alternatively, the intermediate code MCj may be a code in which 1 bits are centrally concentrated. These intermediate codes MCj can be grasped as PWM signals.

The above is an example of the serial interface signal SerIF generated by the light distribution controller 300 . Note that the feedback signal FB has the same format as the serial interface signal SerIF.

The interface circuit 220 decodes this serial interface signal SerIF and generates a plurality of PWM control signals PWM_PIX1 to PWM_PIXn. Specifically, interface circuit 220 includes a decoder 222 . The decoder 222 generates the PWM control signal PWM_PIXj to be supplied to the j-th light-emitting pixel PIXj by combining the j-th bit of each of the m time slots TS1 to TSm. A decoder 222 generates PWM control signals PWM_PIX1 to PWM_PIXn for all pixels.

By switching-driving the j-th light-emitting pixel PIXj according to the PWM control signal PWM_PIXj, the luminance (time average value) of the j-th light-emitting pixel PIXj is the same as that of the pixel pj corresponding to the original light distribution image data IMG_LD. according to the value.

On the other hand, the decoder 330 restores the PWM control signal PWM_PIXz of the target pixel from the feedback signal FB. As described above, feedback signal FB has the same format as serial interface signal SerIF, so decoder 330 is configured to have the same functionality as decoder 222 of interface circuit 220 . That is, the decoder 330 receives the feedback signal FB instead of the serial interface signal SerIF, and generates the PWM control signal PWM_PIXz for the pixel of interest. Specifically, the decoder 330 combines the z-th bits of each of the m time slots TS1 to TSm included in the feedback signal FB to generate a PWM control signal to be supplied to the z-th light-emitting pixel PIXz, which is the pixel of interest. Generate PWM_PIXz'.

As described above, the pixel of interest is not limited to one, and may be all pixels. In that case, the decoder 330 restores the PWM control signals PWM_PIX1' to PWM_PIXn' for all pixels, like the decoder 222 of the interface circuit 220. FIG.

Next, an operation example of the anomaly detector 340 will be described. The abnormality detector 340 can know the waveform (expected waveform) of the PWM control signal PWM_PIXz to be generated inside the patterning device 200 based on the light distribution image data IMG_LD. For example, if the intermediate code MC generated by the pulse width modulator 322 of FIG. 4 is a thermometer code, the thermometer code represents the expected waveform of the PWM control signal PWM_PIXz. If the waveform of the PWM control signal PWM_PIXz' restored by the decoder 330 matches the expected waveform, it can be determined to be normal, and if it does not match, it can be determined to be abnormal. Matching or mismatching of the waveforms may be performed by comparing the pulse widths, or by comparing the lengths of the high section and the low section.

FIG. 6 is a block diagram showing a configuration example (340A) of the anomaly detector 340. As shown in FIG. The anomaly detector 340A includes a TMU (time measurement unit) 342 and a determination section 344. FIG. The TMU 342 measures the length of one or both of the high section T _L and the low section T _L of the PWM control signal PWM_PIXz'. The determination unit 344 generates expected values of the times T _H and T _L measured by the TMU 342 based on the pixel values of the corresponding pixels in the light distribution image data IMG_LD. Then, the determination unit 344 determines whether the time actually measured by the TMU 342 matches or does not match the expected value. If they do not match, the determination unit 344 asserts (for example, high level) the abnormality detection signal ERR. The abnormality detection signal ERR may be an interrupt signal, or may be data including the number of a pixel in which an abnormality has occurred.

The above is the operation of the lamp system 100. According to this lamp system 100, the serial interface signal SerIF, which is the output of the interface circuit 320, is fed back, and the decoder 330 reproduces the PWM control signal PWM_PIX. Therefore, it is possible to detect a state in which an error occurs in the interface circuit 320 and a correct serial interface signal SerIF cannot be generated.

Further, by extracting the feedback signal FB from the middle of the serial signal line 202 or from a portion near the input terminal (ii) of the interface circuit 220, it is possible to detect an abnormality due to waveform distortion or noise in the serial signal line 202. . That is, even if the serial interface signal SerIF is normal at the output end of the interface circuit 320, the serial interface signal SerIF received by the interface circuit 220 may be garbled due to waveform distortion and noise during transmission on the serial signal line 202. have a nature. In this case, if the extraction position of the feedback signal FB is brought closer to the interface circuit 220, the feedback signal FB will be garbled like the serial interface signal SerIF. In this case, since the PWM control signal PWM_PIXz restored based on the feedback signal FB is an erroneous signal, the abnormality detector 340 can determine that it is abnormal.

Next, a modified example will be explained.

(Modification 1)
The configuration of the patterning device 200 to be controlled by the light distribution controller 300 is not particularly limited. For example, patterning device 200 may include a light source that produces a beam with a uniform intensity distribution and a spatial light modulator that patterns the intensity distribution of the light source. Examples of spatial light modulators include DMDs (Digital Micromirror Devices) and liquid crystal panels.

(Modification 2)
The format of the serial interface signal SerIF transmitted from the interface circuit 320 to the patterning device 200 is not limited to that illustrated in FIG.

(Modification 3)
The configuration and determination method of the abnormality detector 340 are not limited to those of FIG. 6 either. Although the TMU is used to measure the time in FIG. 6, the PWM control signal PWM_PIXz' may be converted into a bit string and the bit string pattern may be compared with the expected value pattern.

Although the present disclosure has been described using specific terms based on the embodiments, the embodiments merely illustrate the principles and applications of the present disclosure and/or invention, and the embodiments do not include the claims. Many variations and rearrangements are permissible without departing from the spirit of the invention as defined in its scope.

The present invention relates to a vehicle lamp.

DESCRIPTION OF SYMBOLS 100... Lamp system, 102... Upper controller, 200... Patterning device, 202... Serial signal line, 210... LED array, 220... Interface circuit, 300... Light distribution controller, 302... Vehicle bus interface, 310... Rendering processing part, 320 ... interface circuit, 322 ... pulse width modulator, 324 ... serializer, 330 ... decoder, 340 ... abnormality detector, 342 ... TMU, 344 ... determination unit.

Claims

A light distribution controller for controlling a patterning device comprising a plurality of control elements arranged in an array,
A rendering processing unit for generating multi-gradation light distribution image data defining light distribution, wherein pixel values of pixels of the light distribution image data are PWM (Pulse Width Modulation) for corresponding control elements of the patterning device. ) a drawing processor, which defines the duty cycle of the control signal;
an interface circuit that converts the light distribution image data into a serial interface signal having a signal format required by the patterning device and transmits the signal to the light distribution controller;
a decoder that receives a feedback signal based on the serial interface signal and restores a PWM control signal for a pixel of interest in the patterning device;
an anomaly detector that determines the presence or absence of an anomaly based on the PWM control signal restored by the decoder;
A light distribution controller comprising:
The light distribution controller according to claim 1, wherein the anomaly detector uses a time measurement unit to measure at least one of a high section and a low section of the PWM control signal.
3. The light distribution controller according to claim 1, wherein the decoder restores the PWM control signal with all pixels of the turning device as the pixels of interest.
The light distribution image data includes n pixels,
The interface circuit is
A pulse width modulator for generating n intermediate codes corresponding to n pixels, wherein the intermediate code includes m bits and 1's included in the j-th (1≤j≤n) intermediate code. a pulse modulator, the number of which corresponds to the pixel value of the j-th pixel;
a serializer that converts the n intermediate codes into the serial interface signal;
including
The serial interface signal includes m slots, each slot includes n bits, and m bits forming the j-th intermediate code are assigned to the j-th bit of the m slots. 3. A light distribution controller according to claim 1 or 2.
The light distribution controller according to claim 4, wherein the intermediate code is a thermometer code.
The light distribution controller according to claim 1 or 2, wherein the patterning device is a micro LED.
a patterning device;
A light distribution controller according to claim 1 or 2, which controls the patterning device;
A vehicle lamp system comprising: