JP6879772B2 - Vehicle lighting - Google Patents

Description

The present invention emits light based on a reflective space light modulator having a plurality of mirror elements whose mirror surface can be tilted, a light emitting unit that emits incident light to the space light modulator, and light reflected from the mirror surface. The present invention relates to a technical field of a vehicle lamp equipped with a projection lens for projection.

For example, as disclosed in Patent Document 1 below, as a vehicle lighting fixture, a reflective spatial light modulator (two-dimensional image display) having a plurality of mirror elements (micromirrors 31) whose mirror surface can be tilted freely. A device 30), a light emitting unit (light source 10) that emits incident light to a spatial light modulator, and a projection lens (projection lens 50) that projects light based on the reflected light from the mirror surface are known. There is.

In this type of vehicle lighting equipment, it is possible to form a desired pattern as a light distribution pattern of projected light by controlling the tilt angle of the mirror element.

Japanese Unexamined Patent Publication No. 2015-138763

Here, the mirror element may cause a sticking abnormality in which the tilt angle is fixed at a constant angle due to factors such as foreign matter being mixed in the mechanical portion for changing the tilt angle.
If the mirror element has a sticking abnormality, the original light distribution pattern cannot be formed, and it may be difficult to improve the comfort in vehicle operation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve comfort in vehicle operation.

The vehicle lighting equipment according to the present invention is a reflective space light modulator having a plurality of mirror elements whose mirror surface can be tilted freely, a light emitting unit that emits incident light to the space light modulator, and the mirror surface. Based on a projection lens that projects light based on the reflected light of the above, a light detection unit on which the reflected light from the mirror surface is incident when the mirror surface is in a predetermined tilted state, and a detection signal by the light detection unit. Bei example an abnormality and determining unit, which performs an abnormality determination of the mirror element Te, the light detecting unit, the reflected light from the mirror plane when the mirror element is a non-driven state is provided at a position of incidence, The abnormality determination unit performs the abnormality determination on the condition that the vehicle is stopped .

According to the above configuration, when the mirror element has a sticking abnormality, it is possible to detect the occurrence of the abnormality. In addition, it is not necessary to drive the mirror element for abnormality determination. Further, the abnormality determination can be performed at a timing more appropriate from the viewpoint of vehicle speed.

In the vehicle lamp according to the present invention described above, the photodetector is provided at a position where the reflected light from the mirror surface is incident when the inclination angle of the mirror surface is approximately 0 degrees. It is possible to do.

This makes it possible to perform abnormality determination corresponding to both on-sticking and off-sticking.

In the vehicle lighting equipment according to the present invention described above, when the light detection unit performs light detection, the abnormality determination unit emits light smaller than the amount of light emitted by the light emitting unit in response to a lighting instruction from the vehicle side. It is possible to make it emit light depending on the amount.

As a result, the amount of projected light can be suppressed even when light is projected from the projection lens due to the tilted state of the mirror surface when determining an abnormality.

In the vehicle lamp according to the present invention described above, the photodetector can be configured to perform light detection by a plurality of photodetectors.

This makes it possible to determine the presence or absence of an abnormality in the mirror element for each detection region in the photodetector.

According to the present invention, it is possible to improve the comfort in operating the vehicle.

It is a block diagram for demonstrating the schematic internal structure of the vehicle lamp as an embodiment. It is a figure for demonstrating an example of the arrangement position of a projection lens and a light absorbing part. It is a flowchart which showed the process which concerns on abnormality determination as 1st Embodiment. It is a figure which showed the relationship between the detection time by a light detection part, the light emission time by a light emitting part, and the driving state of a mirror element in an embodiment. It is a figure for demonstrating the arrangement position of the light detection part in 2nd Embodiment. It is a flowchart which showed the process which concerns on abnormality determination as a 2nd Embodiment. It is explanatory drawing about the 1st modification.

Hereinafter, the vehicle lamp 1 as an embodiment of the vehicle lamp of the present invention will be described with reference to the accompanying drawings.

<1. First Embodiment>
[1-1. Configuration of vehicle lighting equipment]
FIG. 1 is a block diagram for explaining a schematic internal configuration of a vehicle lamp 1. Note that FIG. 1 also shows a vehicle-side ECU (Electronic Control Unit) 100 provided outside the vehicle lamp 1.

The vehicle lamp 1 of this example is a lamp as a headlamp (vehicle headlight) in which a pair of left and right lamps are arranged at the front end of the vehicle.
As shown in the figure, the vehicle lamp 1 emits a light emitting unit 2, a reflective spatial light modulator 3 having a plurality of mirror elements 3a, a projection lens 4 that projects light based on incident light, and a light emitting unit 2. The light emitting drive unit 5 to drive, the modulator drive unit 6 to drive the spatial light modulator 3, the controller 7 to control each part of the vehicle lamp 1 based on the instruction from the vehicle side ECU 100, the light detection unit 8, and the light detection unit 8. It is provided with an absorption unit ab.

The light emitting unit 2 has, for example, a light emitting element using an LED (Light Emitting Diode) or the like, and emits incident light to the spatial light modulator 3. The number of light emitting elements included in the light emitting unit 2 may be one or a plurality.

The light emitting drive unit 5 drives the light emitting element in the light emitting unit 2 to emit light based on the power supply voltage supplied from the vehicle-mounted battery.

The spatial light modulator 3 is configured as, for example, a DMD (Digital Micromirror Device: registered trademark), and a plurality of mirror elements 3a having a mirror surface Sm (not shown in FIG. 1) tiltable are arranged in a matrix. .. Each mirror element 3a is individually driven based on a drive signal from the modulator drive unit 6. That is, the modulator driving unit 6 can individually control the inclination angle of the mirror surface Sm in each mirror element 3a.
In this example, the number of mirror elements 3a included in the spatial light modulator 3 is about 600,000 (that is, about 600,000 pixels).

The projection lens 4 projects light to the front of the vehicle based on the reflected light from the mirror surface Sm of each mirror element 3a.

The light absorbing portion ab is made of a material capable of absorbing light, and can absorb the reflected light when the reflected light from each mirror surface Sm is incident.

Here, with reference to FIG. 2, an example of the arrangement position of the projection lens 4 and the light absorbing portion ab in this example will be described.
First, as a premise, the inclination angle θ of the mirror surface Sm will be described. FIG. 2A shows a state when the mirror element 3a is driven in a flat state. The flat state means a state in which the optical axis Ax of the mirror surface Sm becomes vertical when the spatial light modulator 3 is placed horizontally. The optical axis Ax is an axis parallel to the orthogonal axis of the mirror surface Sm.
It is assumed that the inclination angle of the mirror surface Sm in the flat state shown in FIG. 2A is the inclination angle θ = 0 degrees.

FIG. 2B shows a state when the mirror element 3a is turned on, and FIG. 2C shows a state when the mirror element 3a is turned off (non-driving state).
When the mirror element 3a is turned on as shown in FIG. 2B, the mirror surface Sm is inclined to one side by a predetermined angle from the flat state of FIG. 2A. On the other hand, when the mirror element 3a is turned off as shown in FIG. 2C, the mirror surface Sm is tilted from the flat state of FIG. 2A to the other side by a predetermined angle.

In this example, the absolute values of the tilt angle θ in the off state and the tilt angle θ in the on state are substantially the same. That is, in this example, the drive amount of the mirror element 3a for obtaining the flat state shown in FIG. 2A can be expressed as approximately "0.5" when the drive amount when the mirror element 3a is turned on is "1". ..

In this example, in the on state shown in FIG. 2B, the reflected light from the mirror surface Sm is incident on the projection lens 4. In other words, the projection lens 4 is arranged at a position where the reflected light from the mirror surface Sm is incident when the inclination angle θ of the mirror surface Sm is an angle corresponding to the on state.

Further, in this example, in the off state shown in FIG. 2C, the reflected light from the mirror surface Sm is incident on the light absorbing portion ab. That is, the light absorbing portion ab is arranged at a position where the reflected light from the mirror surface Sm is incident when the inclination angle θ of the mirror surface Sm is an angle corresponding to the off state.
In the off state, the reflected light from the mirror surface Sm is not incident on the projection lens 4.

The explanation is returned to FIG.
The photodetector 8 is provided at a position where the reflected light from the mirror surface Sm is incident when the mirror surface Sm is in a predetermined inclined state.
In this example, the photodetector 8 is configured as an image sensor in which a plurality of photoelectric conversion elements are arranged in an array, such as a CCD (Charged-coupled devices) sensor and a CMOS (Complementary metal-oxide-semiconductor) sensor. , The incident light can be detected on a pixel-by-pixel basis.

As schematically shown in FIG. 1, the photodetector 8 is inserted between the light absorbing part ab and the spatial light modulator 3, and at least a part of the reflected light from the mirror surface Sm toward the light absorbing part ab is detected. It is said that it can be incident on the detection surface. That is, in this example, the reflected light from the mirror surface Sm in the mirror element 3a in the off state is incident on the detection surface.

The detection signal by the photodetector 8 is supplied to the controller 7.

The controller 7 is configured to include a microcomputer having a storage device such as a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), and is a vehicle according to a program stored in the ROM or the like. A process for controlling each part of the lighting tool 1 is executed. The controller 7 is capable of mutually performing data communication with the vehicle-side ECU 100 via a predetermined in-vehicle network such as CAN (Controller Area Network).

The controller 7 controls the light emission of the light emitting unit 2 and the modulation operation of the spatial light modulator 3 based on the instruction from the vehicle side ECU 100. Specifically, the controller 7 gives a light emitting instruction of the light emitting unit 2 to the light emitting drive unit 5 in response to a lamp lighting instruction from the vehicle side ECU 7. As a result, the light emitting unit 5 supplies the drive signal of the light emitting element to the light emitting unit 2, and the light emitting unit 2 emits light.
Further, when the controller 7 is supplied with data for instructing the light distribution pattern from the vehicle side ECU 100 in accordance with, for example, ADB (Adaptive Driving Beam) control on the vehicle side, the mirror element 3a in the spatial light modulator 3 is based on the data. Each on / off instruction is given to the modulator drive unit 6. When the spatial light modulator 6 supplies a drive signal to the corresponding mirror element 3a according to the on / off instruction, only the light reflected by the necessary mirror element 3a among the mirror elements 3a is incident on the projection lens 4. The light distribution pattern of the projected light is controlled to a desired pattern.

Further, the controller 7 controls the detection operation by the light detection unit 8. Specifically, the controller 7 of this example controls reading of the image sensor included in the photodetector 8.
The controller 7 of this example performs the process related to the abnormality determination of the mirror element 3a as described below based on the detection signal by the photodetector 8.

[1-2. Abnormality determination processing as the first embodiment]
The process related to the abnormality determination as the first embodiment will be described with reference to the flowchart of FIG. In the following, an example will be given in which the process shown in FIG. 3 is executed as software process by the controller 7 according to the program stored in the storage device such as ROM described above. However, the processing shown in FIG. 3 is not limited to being realized by software, and can also be realized by hardware.
Here, the process shown in FIG. 3 is performed by the controller 7 every time the controller 7 is activated in this example.

In FIG. 3, the controller 7 determines in step S101 whether or not the lamp is lit. This is a process of determining whether or not the light emitting unit 2 is in a state of emitting light in response to the above-mentioned lamp lighting instruction.

If the lamp is not lit, the controller 7 proceeds to step S102, instructs the light emitting drive unit 5 to emit light from the light emitting unit 2, and performs detection processing in the following step S103. That is, the detection operation by the light detection unit 5 is executed, and the detection signal by the light detection unit 8 is acquired. That is, in this example, the image detected by the image sensor is acquired.

Here, each mirror element 3a is turned off in the spatial light modulator 3 unless the lamp is lit. That is, ideally, the reflected light of each mirror element 3a is incident on the detection surface of the photodetection unit 8, and therefore, when the detection process of step S103 is performed, ideally, it is included in the detection image. No dark part is generated due to the abnormal adhesion of the mirror element 3a.

In step S104 following step S103, the controller 7 gives an instruction to stop light emission to the light emitting drive unit 5, and proceeds to step S108.

In this example, in the detection process of step S103, a read operation for one frame of the image sensor is executed. In the case of this example, the frame rate of the image sensor is approximately 30 fps, and the time required for reading one frame is about 33 ms.

On the other hand, if it is determined in the previous step S101 that the lamp is lit, the controller 7 proceeds to step S105 and performs a process of turning off all the mirror elements 3a. That is, the modulator drive unit 6 is instructed to turn off all the mirror elements 3a.
The term "all mirror elements" as used herein means all mirror elements that are subject to abnormality determination, and does not necessarily mean all mirror elements of the spatial light modulator.

In the following step S106, the controller 7 performs the same detection process as in step S103, and then performs the process of canceling the off of the mirror element 3a in step S107. For example, if all the mirror elements 3a were turned on immediately before the execution of step S105, an instruction to turn all the mirror elements 3a on is given to the modulator driving unit 6. Alternatively, when the light distribution pattern is being instructed by the vehicle-side ECU 100, such as when the process of step S105 is being executed while ADB control is being executed, for each mirror element 3a according to the instructed light distribution pattern. An on / off instruction is given to the modulator drive unit 6.
As described above, in step S107, the process of returning the drive state of each mirror element 3a to the drive state immediately before step S105 is performed.
The controller 7 proceeds to step S108 according to the execution of the process of step S107.

In step S108, the controller 7 performs an abnormality determination preparatory process. Specifically, based on the detection signal obtained in the detection process in step S103 or S106, the calculation process necessary for determining the presence or absence of the sticking abnormality of the mirror element 3a is performed.

In this example, since the reflected light from the mirror element 3a turned off is detected, the brightness value of a part of the detected image decreases when the mirror element 3a fixed in the on state is present. .. Therefore, by determining whether or not there is a pixel whose brightness value is equal to or less than a predetermined threshold value in the detected image, it is possible to determine the presence or absence of the mirror element 3a that is abnormally fixed.

However, in this example, since the number of pixels of the mirror element 3a is relatively large, it is extremely unlikely that a person will perceive an abnormality in the light distribution pattern even if a few mirror elements 3a have an abnormality in sticking.
Therefore, in the abnormality determination in this case, for example, when the total number of pixels constituting the detected image is i and the number of pixels whose brightness value is equal to or less than a predetermined threshold value is h, the ratio α = h / i. Is performed by determining whether or not is equal to or greater than a predetermined threshold value t.
In the preparatory process according to step S108 in this case, the process of calculating the above ratio α is performed.

It is also conceivable to adopt a configuration in which each pixel of the image sensor in the photodetection unit 8 can individually detect the reflected light from one corresponding mirror element 3a. In that case, as an abnormality determination, when the total number of mirror elements 3a is m, and the number of mirror elements 3a in which the detected luminance value of the reflected light is equal to or less than a predetermined threshold value is n, the ratio α'= m / It can also be performed as a determination as to whether or not n is equal to or greater than a predetermined threshold value t'.

In step S109 following step S108, the controller 7 determines whether or not there is an abnormality. That is, the presence or absence of abnormality is determined based on the value obtained in the preparatory process of step S108. Specifically, in this example, it is determined whether or not the ratio α is equal to or greater than the threshold value t, and if the ratio α is not equal to or greater than the threshold value t, a determination result is obtained that there is no abnormality. If so, the judgment result that there is an abnormality is obtained.

If it is determined in step S109 that there is no abnormality, the controller 7 ends the process shown in FIG.
On the other hand, if it is determined in step S109 that there is an abnormality, the controller 7 performs the notification process in step S110 and then ends the process shown in FIG. The notification process in step S110 is a process for notifying the vehicle-side ECU 100 that an abnormality has occurred.
Upon receiving the notification, the vehicle-side ECU 100 can execute a response process to the occurrence of an abnormality, for example, notifying the driver that ADB control is impossible and forcibly stopping ADB control.

Here, if it is determined in the previous step S101 that the lamp is not lit, the light emitting unit 2 that should originally be non-light emitting is brought into a light emitting state by the processing of steps S102 to S103. At this time, if the mirror element 3a fixed in the ON state is present, unnecessary light is projected to the front of the vehicle through the projection lens 4.

However, in this example, since the detection time by the detection process in step S103 is relatively short, unnecessary projected light is emitted to a pedestrian or another vehicle even if the mirror element 3a stuck in the ON state is present. There is no risk of being perceived by a person such as a person.

FIG. 4 is a diagram showing the relationship between the detection time by the light detection unit 8, the light emission time by the light emitting unit 2, and the driving state of the mirror element 3a.
As described above, in the detection process of step S103, reading for one frame is executed, so that the detection time Td in FIG. 4 is a relatively short time as one frame period (approximately 33 ms). Therefore, the light emitting time of the light emitting unit 2, which can be expressed as the period from steps S102 to S104, can be suppressed to a short time equivalent to the detection time Td. Therefore, even if the mirror element 3a fixed in the ON state is present, it is possible to prevent unnecessary projected light from being perceived during the detection operation.

<2. Second Embodiment>
[2-1. Configuration of vehicle lighting equipment]
In the second embodiment, the light detection unit 8 detects the reflected light from the mirror element 3a in the flat state.
In the following description, parts that are similar to the parts that have already been explained will be given the same reference numerals and the same step numbers, and the description will be omitted.
In the second embodiment, the configuration of the vehicle lamp 1 is the same as that of the first embodiment except for the arrangement position of the photodetector 8, so the illustration is omitted.

FIG. 5 is a diagram for explaining the arrangement position of the photodetector 8 in the second embodiment.
As shown in FIG. 5A, the photodetector 8 in this case is arranged at a position where the reflected light from the mirror surface Sm is incident when the mirror element 3a is in the flat state (tilt angle = 0 degree). .. The "incident" here is an incident on the detection surface of the photodetector 8.
As shown in FIG. 5B, when the mirror element 3a is on, the reflected light from the mirror surface Sm is incident on the projection lens 4 and not on the photodetector 8. Further, as shown in FIG. 5C, when the mirror element 3a is off, the reflected light from the mirror surface Sm is incident on the light absorbing unit ab and not on the photodetecting unit 8.

In the second embodiment, based on the swing direction (rotation direction) of the mirror surface Sm, the photodetector 8 is located between the projection lens 4 and the light absorption section ab in the swing direction. In other words, it is.

[2-2. Abnormality determination processing as the second embodiment]
The process related to the abnormality determination as the second embodiment will be described with reference to the flowchart of FIG. In the following, an example in which the processing shown in FIG. 6 is also performed as software processing by the controller 7 will be described, but it can also be realized by hardware as in the case of the first embodiment.
The process shown in FIG. 6 is also performed by the controller 7 every time it is started.

In FIG. 6, the controller 7 in this case determines in step S101 whether or not the lamp is lit, and if the lamp is not lit, proceeds to step S102 to instruct the light emitting drive unit 5 to emit light from the light emitting unit 2. , Step S201.

In step S201, the controller 7 performs a process of flattening all the mirror elements 3a. Specifically, the modulator drive unit 6 is instructed to set all the mirror elements 3a in a flat state (in this example, the inclination angle θ = 0 degrees).
In the process of step S201, it is not essential that the inclination angle θ = 0 degrees, and the reflected light from all the mirror elements 3a that are the targets of abnormality determination are arranged as shown in FIG. A slight difference is allowed as long as it is within the range of being incident on the detection surface of the light detection unit 8.

In response to the execution of the process of step S201, the controller 7 performs the detection process of step S202. Since the detection process is the same as the process in step S103 above, duplicate description is avoided.

In step S203 following step S202, the controller 7 gives an instruction to stop light emission to the light emitting drive unit 5, further performs a process of returning all mirror elements 3a to the off state in step S204, and then prepares for abnormality determination in step S108. Proceed to processing.

In this case as well, in the detection process of step S202, the read image for one frame is acquired from the image sensor of the photodetector 8, so that the light emission time of the light emitting unit 2 for light detection (from steps S201 to S203). Time) is relatively short.

On the other hand, if it is determined in the previous step S101 that the lamp is lit, the controller 7 proceeds to step S205, performs a process for flattening all the mirror elements 3a, and then performs a detection process in step S206. Do. The detection process in step S206 is the same as the detection process in step S103.
In response to the execution of the detection process in step S206, the controller 7 performs a process of releasing the flat state in step S207, and proceeds to the process for preparing for abnormality determination in step S108. The process of step S207 is the same as the process of step S107.

Since the processing after step S108 is the same as that in FIG. 3, the description thereof will be omitted.

In the second embodiment, since the light detection unit 8 detects the mirror element 3a in the flat state, it is possible to detect not only the abnormality fixed in the on state but also the abnormality fixed in the off state.
Therefore, the abnormality determination function can be improved.

<3. Modification example>
[3-1. First modification]
The amount of light emitted by the light emitting unit 2 when the light detection unit 8 performs detection can be smaller than the amount of light emitted in response to a lamp lighting instruction from the vehicle side.
Generally, as a vehicle headlight, a constant amount of light is maintained when the light emitting unit 2 emits light in response to a lamp lighting instruction. That is, a constant light emission amount (hereinafter referred to as "normal light emission amount") is defined as the light emission amount of the light emitting unit 2 in response to the lamp lighting instruction. As shown in FIG. 7, the amount of light emitted by the light emitting unit 2 when the light detection unit 8 performs detection can be made smaller than the normal amount of light emitted.
FIG. 7A shows a case where the light detection unit 8 performs detection when the lamp is not lit. In this case, when the light detection unit 8 detects the light, the light emitting unit 2 is made to emit light with a light emitting amount smaller than the normal light emitting amount.
FIG. 7B shows a case where the light detection unit 8 performs detection while the lamp is lit in response to the lamp lighting instruction. In this case, since the light emitting unit 2 emits light according to the normal light emitting amount, when the light detecting unit 8 performs detection, the light emitting amount by the light emitting unit 2 is reduced to a light emitting amount smaller than the normal light emitting amount.

In the case of the first modification, the light emitting drive unit 5 is configured so that the amount of light emitted by the light emitting unit 2 can be adjusted. Then, in order to realize the operation of FIG. 7A described above, the controller 7 sets the light emitting unit 2 with a light emitting amount smaller than the normal light emitting amount as a light emitting instruction in the previous step S102 (FIGS. 3 and 6). An instruction to emit light is given to the light emitting drive unit 5.
Further, in order to realize the operation of FIG. 7B, a dimming instruction process is provided between steps S101 and S105 in FIG. 3 and between steps S101 and S205 in FIG. 6, respectively. That is, as the dimming instruction process, the controller 7 instructs the light emitting drive unit 5 to reduce the light emitting amount of the light emitting unit 2 to a light emitting amount smaller than the normal light emitting amount.

In the first modification, the detection time by the photodetector 8 is set to be as short as one frame, for example, as in the case of the first and second embodiments. The dimming time can be shortened. That is, it is possible to prevent the dimming state associated with the detection from being perceived.

[3-2. Second variant]
In the embodiment, a plurality of photoelectric conversion elements (photodetecting elements) arranged in an array are used as the photodetector 8, and it is determined for each photoelectric conversion element whether or not the detection value is equal to or less than a predetermined threshold value. An example is given in which the presence or absence of an abnormality is determined based on the comparison result between the number of photoelectric conversion elements that are equal to or less than the predetermined threshold value and the threshold value α (or α').
At this time, the presence or absence of an abnormality can be determined in consideration of the position of the mirror element 3a in which the abnormality has occurred. For example, in general, with respect to the light distribution pattern of the projected light in the headlight for a vehicle, the amount of light in the central portion of the light projection region is increased. In such a case, if the mirror element 3a located at the center of the spatial light modulator 3 has an off-sticking abnormality, the decrease in the amount of light becomes noticeable. In consideration of these points, for determination of the presence or absence of an abnormality, for example, a region located in the center of the photodetection region of the photodetector 8 (hereinafter referred to as "center detection region") and other regions (hereinafter "" It is also possible to make the level of the abnormality judgment condition different depending on the "peripheral detection area"). As a specific method, for example, the following methods (1) and (2) can be considered.
(1)
A threshold value Tc for the central detection area and a threshold value Td for the peripheral detection area (however, Td> Tc) are set.
The number of photoelectric conversion elements whose detection values are equal to or less than a predetermined threshold value in each of the central detection region and the peripheral detection region is counted (count number in the central detection region = c, count number in the peripheral detection region = d).
The ratio βc = c / C and the ratio βd = d / D are calculated assuming that the total number of photoelectric conversion elements in the central detection region = C and the total number of photoelectric conversion elements in the peripheral detection region = D.
A central discrimination process for determining whether or not the ratio βc is equal to or higher than the threshold value Tc and a peripheral discrimination process for determining whether or not the ratio βd is equal to or higher than the threshold value Td are performed.
Only when a negative result is obtained in both the center discrimination process and the peripheral discrimination process, the determination result that there is no abnormality is obtained, and in other cases, the determination that there is an abnormality is obtained.
(2)
A common threshold value Ta is set for the central detection area and the peripheral detection area, and a coefficient kc for the central detection area is set (however, kc> 1).
After calculating the ratio βc = c / C and the ratio βd = d / D by the same method as in (1) above, the ratio βc is multiplied by the coefficient kc.
As a process for discriminating against the center, it is determined whether or not βc × kc is equal to or higher than the threshold value Ta, and as a process for discriminating against the periphery, it is determined whether or not the ratio βd is equal to or greater than the threshold value Ta.
Only when a negative result is obtained in both the center discrimination process and the peripheral discrimination process, the determination result that there is no abnormality is obtained, and in other cases, the determination that there is an abnormality is obtained.

According to the above method, stricter conditions are set as abnormality determination conditions for the central region where the decrease in light intensity is likely to be noticeable when an abnormality occurs in the mirror element 3a, and the abnormality determination condition is set for the peripheral region where the decrease in light intensity is less noticeable. More relaxed conditions are set as.
As a result, even if an abnormality occurs in the mirror element 3a, it is possible to prevent the determination that there is an abnormality even in a case where the actual damage does not occur (or is extremely small) as the generated portion. That is, it is possible to make an appropriate abnormality determination according to the part where the abnormality occurs.

Here, what is important in the second modification is that the photodetector 8 detects light by a plurality of photodetectors. As a result, it is possible to determine the presence or absence of abnormality in the mirror element 3a for each detection region in the light detection unit 8. Therefore, as illustrated above, the determination condition level for determining the presence or absence of abnormality in the mirror element 3a for each detection region. Therefore, it is possible to make an appropriate abnormality determination according to the part where the abnormality occurs.

[3-3. Other variants]
In the above, the presence or absence of abnormality is determined based on only one detection result by the photodetector 8, but the presence or absence of abnormality can also be determined based on a plurality of detection results.
For example, the processing for abnormality determination (excluding the notification processing in step S110) shown in FIGS. 3 and 6 is executed a plurality of times in a predetermined cycle, and the abnormality determination results (determination in step S109) obtained by the plurality of times are executed. It is also possible to make a final determination of the presence or absence of an abnormality based on the result).
For example, it is conceivable to count the number of times that the determination result of abnormality is obtained as the abnormality determination result for the above-mentioned multiple times, and to obtain the final determination result of abnormality when the count value is equal to or more than a predetermined threshold value. Be done. Alternatively, it is also conceivable to count the number of times that the determination result of abnormality is continuously obtained, and to obtain the final determination result of abnormality when the count value is equal to or more than a predetermined threshold value.

By determining the presence or absence of an abnormality based on the detection results of a plurality of times by the photodetector 8 as described above, the accuracy of the determination of the presence or absence of an abnormality can be improved.

Further, in the above, the example in which the controller 7 performs the processing for abnormality determination shown in FIGS. 3 and 6 for each activation has been given, but various conceivable conditions for starting the processing for abnormality determination can be considered.
For example, the process for determining the abnormality can be started according to the conditions based on the vehicle speed information acquired from the vehicle side. For example, the controller 7 can start the processing of FIGS. 3 and 6 on the condition that the vehicle is stopped (vehicle speed = 0 km / h) based on the vehicle speed information. At this time, strictly speaking, the condition is not limited to the vehicle speed = 0 km / h, but it can also be the condition that the vehicle speed is 5 km / h or less, which can be regarded as being almost stopped.
According to the above method, the abnormality determination can be performed at a timing estimated to be appropriate from the viewpoint of vehicle speed.

Alternatively, the process for determining the abnormality shown in FIGS. 3 and 6 can be started on condition that a lamp lighting instruction is given from the vehicle side. In that case, the determination process in step S101 and the process when a negative result is obtained in the determination process (for example, S102 to S104) are omitted. Since the process for determining the abnormality is performed while the lamp is lit, it is possible to prevent the originally unnecessary light caused by the mirror element 3a fixed on the lamp from being projected independently through the projection lens 4.
Further, the process for determining the abnormality shown in FIGS. 3 and 6 may be started on the condition that the lamp lighting instruction is not given. In that case, it is possible to prevent an originally unnecessary dark portion due to the mirror element 3a fixed off from being generated in the light distribution pattern of the projected light.

<4. Summary of embodiments>
As described above, the vehicle lighting equipment (1) of the embodiment includes a reflection type spatial light modulator (3) having a plurality of mirror elements (3a) whose mirror surface (Sm) can be tilted freely. , A light emitting part (2) that emits incident light to the spatial light modulator, a projection lens (4) that projects light based on the reflected light from the mirror surface, and a mirror when the mirror surface is in a predetermined tilted state. It includes a light detection unit (8) to which the reflected light from the surface is incident, and an abnormality determination unit (controller 7) that determines an abnormality of the mirror element based on the detection signal by the light detection unit.

According to the above configuration, when the mirror element has a sticking abnormality, it is possible to detect the occurrence of the abnormality.
Therefore, it is possible to take appropriate measures on the vehicle side in response to the abnormality detection, and it is possible to improve the comfort in vehicle operation.

Further, in the vehicle lamp of the embodiment, the photodetector is provided at a position where the reflected light from the mirror surface is incident when the mirror element is in the non-driving state (first embodiment).

This eliminates the need to drive the mirror element for abnormality determination.
Therefore, it is possible to suppress the power consumption for performing the abnormality determination.
Further, as illustrated in the embodiment, in the configuration in which the light is projected through the projection lens when the mirror element is in the driving state, it is possible to prevent the originally unnecessary light from being projected due to the abnormality determination. It is possible to prevent it from being perceived by a person such as a pedestrian or another vehicle driver.

Further, in the vehicle lamp of the embodiment, the photodetector is provided at a position where the reflected light from the mirror surface is incident when the inclination angle of the mirror surface is set to about 0 degree (second embodiment). ).

This makes it possible to perform abnormality determination corresponding to both on-sticking and off-sticking.
Therefore, the abnormality determination function can be improved.
Further, since it is not necessary to arrange the photodetector between the light absorbing unit and the spatial light modulator, it is possible to prevent the photodetector from interfering with the absorption of reflected light by the light absorbing unit.

Furthermore, in the vehicle lamp of the embodiment, when the photodetector detects light, the abnormality determination unit emits light with a light emission amount smaller than the light emission amount according to the lamp lighting instruction from the vehicle side. I'm letting you.

As a result, the amount of projected light can be suppressed even when light is projected from the projection lens due to the tilted state of the mirror surface when determining an abnormality.
Therefore, it is possible to further reduce the possibility that the originally unnecessary projected light is perceived by a person such as a pedestrian or another vehicle driver.

Further, in the vehicle lamp of the embodiment, the photodetector performs light detection by a plurality of photodetectors.

This makes it possible to determine the presence or absence of an abnormality in the mirror element for each detection region in the photodetector.
Therefore, it is possible to make an appropriate abnormality determination according to the part where the abnormality occurs in the spatial light modulator.

Further, in the vehicle lamp of the embodiment, the abnormality determination unit performs abnormality determination according to the conditions relating to the vehicle speed.

As a result, the abnormality determination can be performed at a timing estimated to be appropriate from the viewpoint of vehicle speed.

Furthermore, in the vehicle lighting equipment of the embodiment, the abnormality determination unit makes an abnormality determination on the condition that the vehicle is stopped.

As a result, the abnormality determination can be performed at a timing more appropriate from the viewpoint of vehicle speed.

In the above, the case where the light is projected through the projection lens 4 when the mirror element 3a is on is illustrated, but conversely, the light through the projection lens 4 is performed when the mirror element 3a is in the off state. It may be configured so that projection is performed. At this time, in the first embodiment, the mirror element 3a is turned on at the time of light detection.
Further, the light detection unit 8 is not limited to the one that performs light detection by an image sensor, and may be, for example, one that performs light detection by an optical position sensor (PSD: Position Sensitive Detector).
The vehicle lighting fixture according to the present invention is not limited to the application to vehicle headlights, and can be widely and suitably applied to vehicle lighting fixtures in general.

1 Vehicle lighting, 2 Light emitter, 3 Spatial light modulator, 3a Mirror element, Sm mirror surface, 4 Projection lens, 5 Light emission drive, 6 Modulator drive, 7 Controller, 8 Photodetector, 100 Vehicle side ECU , Ab Absorbent

Claims (4)

A reflective spatial light modulator with multiple mirror elements whose mirror surface can be tilted freely,
A light emitting unit that emits incident light to the spatial light modulator,
A projection lens that projects light based on the reflected light from the mirror surface, and
A photodetector to which light reflected from the mirror surface is incident when the mirror surface is in a predetermined tilted state.
E Bei and a abnormality determination unit that performs abnormality determination the mirror element based on a detection signal from the light detecting unit,
The photodetector
It is provided at a position where the reflected light from the mirror surface when the mirror element is in the non-driving state is incident.
The abnormality determination unit is a vehicle lamp that determines the abnormality on the condition that the vehicle is stopped. The photodetector
The vehicle lamp according to claim 1, provided at a position where the reflected light from the mirror surface is incident when the inclination angle of the mirror surface is set to approximately 0 degrees. The abnormality determination unit
The vehicle lighting device according to claim 1 or 2 , wherein when the light detecting unit performs light detection, the light emitting unit emits light with a light emitting amount smaller than the light emitting amount according to a lamp lighting instruction from the vehicle side. The vehicle lamp according to any one of claims 1 to 3 , wherein the photodetector detects light by a plurality of photodetectors.

Images