Light source device and distance measuring system

Abstract

To precisely detect an abnormality.SOLUTION: A light source device includes: a plurality of light-emitting elements arranged at least in a first direction; a selection unit for selecting a part of the plurality of light-emitting elements as light-emitting targets; and an abnormality detection unit for detecting an abnormality that the terminal voltage of a light-emitting element of the light-emitting elements which was not selected by the selection unit changed instantly.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a light source device and a distance measuring system. [Background technology]

[0002] True-Solid-State LiDAR (Light Detection And Ranging) using VCSEL (Vertical Cavity Surface Emitting Laser) has the advantage of having no moving parts, making it less prone to failure and less expensive than existing MEMS (Micro Electro Mechanical Systems) LiDAR.

[0003] On the other hand, in the case of LiDAR using the True-Solid-State method, in addition to the need to ensure eye safety by meeting the safety standards for laser light, the issue of preventing a decrease in distance measurement accuracy due to VCSEL failure is also an issue. For example, a technology has been proposed in which multiple laser diodes are connected in series to increase the reverse breakdown voltage (see Patent Document 1). As a result, Patent Document 1 makes it possible to suppress unintended light emission due to breakdown in the voltage resistance of the laser diode, as well as unintended light emission due to charge flowing into a laser diode with the anode selected and the cathode unselected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2022-526998 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although Patent Document 1 can suppress unintended light emission, it cannot detect the abnormal part. If the abnormal part can be detected, unintended light emission can be suppressed without increasing the reverse breakdown voltage as in Patent Document 1.

[0006] Therefore, the present disclosure provides a light source device and a distance measuring system that can detect an abnormality with high accuracy. [Means for solving the problem]

[0007] In order to solve the above problems, according to the present disclosure, there is provided a liquid crystal display device comprising: a plurality of light emitting elements arranged in at least a first direction; A selection unit that selects some of the light-emitting elements from the plurality of light-emitting elements as light-emitting targets; and an abnormality detection unit that detects an abnormality caused by an instantaneous change in a terminal voltage of a light-emitting element not selected by the selection unit among the plurality of light-emitting elements. A light source device is provided.

[0008] The selection unit applies a voltage equal to or higher than a first voltage between an anode and a cathode of a light emitting element to be emitted, and prevents a voltage equal to or higher than the first voltage from being applied between an anode and a cathode of a light emitting element that is not to be emitted; The abnormality detection section may detect the abnormality in which a voltage of at least one of an anode or a cathode of a light-emitting element not selected by the selection section instantaneously fluctuates by a second voltage or more.

[0009] The abnormality detection section may detect a short circuit between a light emitting element selected by the selection section and a light emitting element not selected by the selection section.

[0010] The abnormality detection unit may detect that the voltage of at least one of the anode or cathode of the non-selected light-emitting element instantaneously fluctuates by more than the second voltage due to a voltage change in at least one of the anode or cathode of the light-emitting element selected by the selection unit.

[0011] the abnormality detection unit is a first circuit connected to at least one of an anode or a cathode of a light emitting element not selected by the selection unit, the first circuit blocking a DC component and passing an AC component; The device may further include a second circuit that outputs an abnormality detection signal indicating that the abnormality has been detected based on the output signal of the first circuit.

[0012] The first circuit may include a capacitor connected to at least one of the anode and the cathode of a light-emitting element not selected by the selection section.

[0013] The first circuit may include a high-pass filter having a first resistor connected to the capacitor and passing signals having a predetermined frequency or higher.

[0014] The first circuit may include a bandpass filter having an inductor and a first resistor connected to the capacitor, and passing signals in a predetermined frequency band.

[0015] the first circuit has a second resistor having one end connected to the capacitor and the other end connected to the anode or cathode of the light-emitting element; The second resistor may suppress the amplitude of a signal input from the anode or cathode of the light emitting element.

[0016] The second circuit may include a flip-flop that outputs the abnormality detection signal in synchronization with a change in the signal level of the output signal of the first circuit.

[0017] The plurality of light emitting elements are arranged in a first direction and a second direction intersecting each other, and a first light source group including two or more light emitting elements arranged in the first direction is arranged in a plurality of pieces in the second direction, and a second light source group including two or more light emitting elements arranged in the second direction is arranged in a plurality of pieces in the first direction, The selection unit is a plurality of first selectors that select whether or not to apply a first potential to each of the plurality of first light source groups arranged in the second direction; a plurality of second selectors that select whether or not to apply a second potential to each of the plurality of second light source groups arranged in the first direction; The anomaly detection unit may include a plurality of anomaly detectors connected to at least one of a plurality of first light source groups arranged in the second direction or a plurality of second light source groups arranged in the first direction.

[0018] the first potential is applied to the anodes of two or more light-emitting elements included in the first light source group selected by the plurality of first selectors; The second potential may be applied to cathodes of two or more light emitting elements included in the second light source group selected by the second selectors.

[0019] The light emitting device may further include a drive control unit that controls the selection unit not to select at least two or more light emitting elements caused by the abnormality among the plurality of light emitting elements when the abnormality detection unit detects the abnormality.

[0020] The drive control unit may control the selection unit so that it does not select a light-emitting element that was not selected by the selection unit in which the abnormality was detected and a light-emitting element that was selected by the selection unit that caused the abnormality in that light-emitting element.

[0021] The drive control unit may cause the selection unit to select a light emitting element not caused by the abnormality from among the plurality of light emitting elements.

[0022] The drive control unit may stop light emission of the plurality of light-emitting elements when the abnormality detection unit detects the abnormality.

[0023] When an abnormality is detected in any of the light-emitting elements included in any of the first light source groups among the multiple first light source groups, the drive control unit may control the selection unit not to select the first light source group including the light-emitting element that is the target of light emission that caused the abnormality and the first light source group including the light-emitting element in which the abnormality was detected.

[0024] The drive control unit may be configured to control such that, when an abnormality is detected in any of the light-emitting elements included in any of the second light source groups among the plurality of second light source groups, the selection unit does not select the second light source group including the light-emitting element that is the target of light emission that caused the abnormality and the second light source group including the light-emitting element in which the abnormality was detected.

[0025] a light emission control unit that specifies a light emission sequence of the plurality of light emitting elements; The abnormality detection section may notify the light emission control section of the detected abnormality.

[0026] According to the present disclosure, there is provided a light source device having a plurality of light emitting elements arranged in at least a first direction; a light receiving section having a plurality of light receiving elements that receive light emitted by the plurality of light emitting elements and reflected by an object; a distance measuring unit that measures a distance to the object based on light emitted by the plurality of light emitting elements and reflected light received by the light receiving unit, The light source device includes: A selection unit that selects some of the light-emitting elements from the plurality of light-emitting elements as light-emitting targets; an abnormality detection unit that detects an abnormality caused by an instantaneous change in a terminal voltage of a light-emitting element not selected by the selection unit among the plurality of light-emitting elements, A ranging system is provided. [Brief description of the drawings]

[0027] [Figure 1] 1 is a block diagram showing a schematic configuration of a distance measuring system including a light source device according to a first embodiment. [Diagram 2] FIG. 2 is a schematic perspective view of a laminate on which the light source device of FIG. 1 is mounted. [Diagram 3] FIG. 2 is a cross-sectional view showing the structure of a light source device. [Figure 4] 1 is a circuit diagram of a first configuration example of a light source device according to an embodiment of the present disclosure. [Diagram 5] 1A and 1B are diagrams illustrating an example of an abnormality in a light source device according to an embodiment of the present disclosure. [Figure 6A]FIG. 4 is a diagram showing a detailed configuration of an abnormality detection unit according to an embodiment of the present disclosure. [Figure 6B] FIG. 4 is a circuit diagram of a first modified example of the first circuit. [Figure 6C] FIG. 11 is a circuit diagram of a second modified example of the first circuit. [Figure 7] FIG. 4 is a circuit diagram of a second configuration example of a light source device according to an embodiment of the present disclosure. [Figure 8] FIG. 4 is a circuit diagram of a light source device used in a simulation to confirm the operation of an abnormality detection unit. [Figure 9] 9 is a timing chart of a plurality of signals input to and output from the light source device of FIG. 8. [Figure 10] FIG. 1 is a diagram illustrating a configuration of a distance measuring system according to an embodiment of the present disclosure. [Figure 11] FIG. 1 is a block diagram showing an example of a schematic configuration of a vehicle control system. [Figure 12] FIG. 4 is an explanatory diagram showing an example of the installation positions of an outside-vehicle information detection unit and an imaging unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of a light source device and a distance measuring system will be described with reference to the drawings. The following description will focus on the main components of the light source device and the distance measuring system, but the light source device and the distance measuring system may include components and functions that are not shown or described. The following description does not exclude components and functions that are not shown or described.

[0029] (Embodiment) Fig. 1 is a block diagram showing a schematic configuration of a distance measuring system 2 including a light source device 1 according to an embodiment of the present disclosure. The distance measuring system 2 in Fig. 1 includes the light source device 1, a distance measuring device 3, and an overall control unit 4. In this specification, an example of a distance measuring system using a dToF (direct Time of Flight) method will be described, but the light source device 1 of the present disclosure is also applicable to a distance measuring system using an iToF (indirect Time of Flight) method.

[0030] The light source device 1 has a plurality of light-emitting elements arranged in one or two dimensions. The plurality of light-emitting elements repeatedly emit light emission pulse signals at a predetermined time interval. The light source device 1 can scan the optical signals emitted by the plurality of light-emitting elements in a predetermined two-dimensional space. There is no restriction on the specific method for scanning the optical signals. The overall control unit 4 controls the light source device 1 and the distance measuring device 3.

[0031] The distance measuring device 3 has a pixel array section (light receiving section) 10, a distance measuring section 11, a signal processing section 12, a control section 13, a clock generating section 14, a light source control section 15, and a drive circuit 16. The distance measuring section 11 has a time-to-digital converter (TDC) 17, a histogram generating section 18, and a distance measuring control section 19. At least one of the distance measuring device 3 and the overall control section 4 can be integrated into the light source device 1.

[0032] The pixel array unit 10 has a plurality of pixels arranged in one or two dimensions. Each pixel has a light receiving element 10a. The light receiving element 10a is, for example, a SPAD (Single Photon Avalanche photo Diode). In the following, an example in which each pixel has a SPAD will be mainly described. Each pixel may have a quench circuit (not shown). In an initial state, the quench circuit supplies a reverse bias voltage between the anode and cathode of the SPAD, the potential difference of which exceeds the breakdown voltage. After the SPAD detects a photon, the drive circuit 16 supplies a reverse bias voltage to the SPAD via the corresponding quench circuit to prepare for detection of the next reflected light pulse signal.

[0033] The TDC 17 generates a digital signal corresponding to the reception time of the reflected optical pulse signal received by the SPAD with a predetermined time resolution.

[0034] The histogram generating unit 18 generates a histogram with a bin width according to the time resolution of the TDC 17, based on the digital signal generated by the TDC 17. The bin width is the width of each frequency unit that constitutes the histogram.

[0035] The signal processing unit 12 includes a distance calculation unit 12a which calculates the distance to an object by, for example, calculating the position of the center of gravity of the reflected light pulse signal based on the histogram.

[0036] The control unit 13 controls the pulse width and light emission timing of the light emission pulse signal emitted by the light source device 1 via the light source control unit 15. In addition, the control unit 13 controls the processing operations of each unit in the distance measuring device 3.

[0037] The clock generating unit 14 generates a clock signal used by the TDC 17 and the histogram generating unit 18. The clock generating unit 14 generates the clock signal using, for example, a PLL circuit (not shown). The clock generating unit 14 also supplies the generated clock signal to the light source control unit 15. The light source control unit 15 controls the light emission timing of the light source device 1 in synchronization with this clock signal.

[0038] The drive circuit 16 performs quench control to restore the cathode voltage to its original voltage when the SPAD detects light and the cathode voltage drops.

[0039] The light source device 1 of FIG. 1 can be configured as a laminated body in which a plurality of chips are stacked. FIG. 2 is a schematic perspective view of a laminated body in which the light source device 1 of FIG. 1 is mounted. The laminated body of FIG. 2 has a first chip 21 and a second chip 22 stacked on the first chip 21. For example, a plurality of light emitting elements are arranged on the first chip 21. At least a part of the light source device 1 of FIG. 1 other than the light emitting elements is arranged on the second chip 22. The first chip 21 and the second chip 22 are joined by Cu-Cu bonding, vias, bumps, or the like. In addition, at least a part of the distance measuring device 3 and the overall control unit 4 of FIG. 1 may be arranged on the first chip 21 or the second chip 22. Furthermore, the light source device 1 of FIG. 1 may be configured as a laminated body in which three or more chips are stacked.

[0040] 3 is a cross-sectional view showing the structure of light source device 1. As described above, light source device 1 has a plurality of light-emitting elements 30. The plurality of light-emitting elements 30 are disposed between substrates 31 and 32 facing each other, and are formed by processing a laminated film 33 on substrate 31 into a mesa shape.

[0041] The substrate 31 is, for example, an LD (Laser Diode) substrate, and is formed of a compound semiconductor such as GaAs (gallium arsenide). The surface of the substrate 31 facing the substrate 32 is the front surface, and the laser light is emitted from the back side of the substrate 31. The laminated film 33 includes a multilayer reflective layer, a spacer layer, an active layer, and the like, which are opposed to each other, and the laser light generated in the active layer is resonated between the opposed multilayer reflective layers to improve the light intensity, and is emitted from the back side of the substrate. Thus, the light source device 1 in FIG. 3 is a back-illuminated type. In this specification, the light emitting element 30 having the layer structure as shown in FIG. 3 is called a VCSEL structure.

[0042] The substrate 31 includes a plurality of pads 34 and a common electrode 35. The pads 34 are composed of, for example, a contact electrode, a reflective electrode, and a pad electrode. The pads 34 have either an anode electrode or a cathode electrode (for example, an anode electrode) of the light-emitting element 30. The common electrode 35 is composed of the other of the anode electrode and the cathode electrode (for example, a cathode electrode). When viewed from the substrate 31 side, the pads 34 are disposed on the upper surface of each light-emitting element 30. Similarly, the common electrode 35 is disposed on the upper surface and side surface of the laminated film 33 disposed on the end side of the substrate 31. The common electrode 35 is also disposed on the lowermost layer side of the laminated film 33 of the plurality of light-emitting elements 30 when viewed from the substrate 31 side.

[0043] The substrate 32 is, for example, an LDD (Laser Diode Driver) substrate, and has a plurality of pads 36 for supplying drive signals to a plurality of light emitting elements 30. A bonding layer 37 is disposed on the plurality of pads 36, and the pads 36 of the substrate 32 are bonded to the corresponding pads 34 of the substrate 31 via the bonding layer 37. The bonding layer 37 is a laminated film including a solder material or the like. An underfill layer may be injected into the gap between the substrates 31 and 32 to protect the bonded portions of the substrates 31 and 32 and prevent peeling or the like.

[0044] 4 is a circuit diagram of a first configuration example of a light source device 1 according to an embodiment of the present disclosure. The light source device 1 includes a plurality of light emitting elements 30 and a plurality of transistors (second selectors) MP 1 ~MP j and a plurality of transistors (first selectors) MN 1 ~MN i The light emitting device includes a plurality of abnormality detection units 41, a light emission control unit 42, and a drive control unit 43.

[0045] The plurality of light-emitting elements 30 are arranged in a first direction X and a second direction Y that intersect with each other. In this specification, the plurality of light-emitting elements 30 arranged in the first direction X are referred to as a first light source group, and the plurality of light-emitting elements 30 arranged in the second direction Y are referred to as a second light source group. The first light source group is arranged in multiple in the second direction Y, and the second light source group is arranged in multiple in the first direction X.

[0046] Multiple transistors MP 1 ~MP j(hereinafter, transistors MP) are arranged corresponding to the multiple first light source groups, respectively, and switch whether or not to select the corresponding first light source group. For example, a PMOS (P channel Metal-Oxide-Semiconductor) transistor is used as the transistor MP. The source of the transistor MP is connected to a high-voltage power supply (not shown), and the drain is connected to the anodes of the multiple light-emitting elements 30 of the corresponding first light source group. The transistor MP is turned on by, for example, applying a low-level voltage to the gate, and sets the potential of the anodes of the multiple light-emitting elements 30 of the corresponding first light source group to a potential (first potential) based on the voltage of the high-voltage power supply. The state in which the transistor MP sets the potential of the anodes of the multiple light-emitting elements 30 of the corresponding first light source group to the first potential is also called a state in which the first light source group is selected.

[0047] Multiple transistors MN 1 ~MN i (hereinafter, transistors MN) are arranged corresponding to the multiple second light source groups, respectively, and switch whether or not to select the corresponding second light source group. For example, an NMOS (N channel Metal-Oxide-Semiconductor) transistor is used as the transistor MN. The drain of the transistor MN is connected to the cathodes of the multiple light-emitting elements 30 of the corresponding second light source group, and the source is connected to, for example, a reference voltage (for example, ground) node. For example, the transistor MN is turned on by applying a high-level voltage to the gate, and sets the potential of the cathodes of the multiple light-emitting elements 30 of the corresponding second light source group to a potential (second potential) based on the voltage of the reference voltage node. The state in which the transistor MN sets the potential of the cathodes of the multiple light-emitting elements 30 of the corresponding second light source group to the second potential is also called a state in which the second light source group is selected.

[0048] The light-emitting element 30 can emit light by applying a first potential to the anode from the transistor MP and applying a second potential to the cathode from the transistor MN, which generates a voltage (first voltage) between the anode and the cathode. The state in which the transistors MP and MN apply the first potential and the second potential to the anode and the cathode of the light-emitting element 30, respectively, is also called a state in which the light-emitting element 30 is selected.

[0049] In this specification, the transistors MP and MN are also referred to as a selection unit. As described above, the selection unit can select some of the light-emitting elements 30 in the light source device 1 as light-emitting targets. The selection unit applies a voltage equal to or greater than a first voltage between the anode and cathode of the light-emitting elements 30 that are targets for light emission, while preventing a voltage equal to or greater than the first voltage from being applied between the anode and cathode of the light-emitting elements 30 that are not targets for light emission.

[0050] The light source device 1 in Fig. 4 has j first light source groups arranged in the second direction Y, and i second light source groups arranged in the first direction X. That is, the light source device 1 in Fig. 4 has i x j light emitting elements 30 arranged two-dimensionally. In addition, j transistors MP (MP 1 ~MP j ) are arranged. For the i second light source groups, i transistors MN (MN 1 ~MN i ) and i anomaly detection units 41 are arranged.

[0051] Each abnormality detection unit 41 is used to detect abnormal voltage fluctuations in the anode or cathode of each light-emitting element 30 in the corresponding second light source group. More specifically, it detects an abnormality in which the voltage of the anode or cathode of a light-emitting element 30 not selected by the selection unit fluctuates by a predetermined voltage (second voltage) or more.

[0052] One of the input terminals of the abnormality detection unit 41 is connected to the cathodes of the plurality of light-emitting elements 30 of the corresponding second light source group and the drain of the corresponding transistor MN. The other input terminal of the abnormality detection unit 41 is connected to the gate of the corresponding transistor MN. When the corresponding transistor MN is in the on state, the abnormality detection unit 41 is in the off state and does not detect abnormalities. When the corresponding transistor MN is in the off state, the abnormality detection unit 41 is in the on state and is able to detect abnormalities. Each abnormality detection unit 41 in FIG. 4 can detect an abnormality in the corresponding second light source group. The abnormality detection unit 41 notifies the light emission control unit 42 of the detected abnormality.

[0053] The abnormality detection unit 41 may be provided for each first light source group. In this case, one of the input terminals of the abnormality detection unit 41 is connected to the anodes of the light emitting elements 30 of the corresponding first light source group and the drain of the corresponding transistor MP. The other input terminal of the abnormality detection unit 41 is connected to the gate of the corresponding transistor MP. This allows each abnormality detection unit 41 to detect an abnormality in the corresponding first light source group.

[0054] The light emission control unit 42 controls the drive control unit 43. The light emission control unit 42 sends a control signal including the light emission sequence of the plurality of light emitting elements 30 to the drive control unit 43. The drive control unit 43 controls the i transistors MN (MN 1 ~MN i ) gate voltage. Furthermore, when the light emission control unit 42 is notified of an abnormality from at least one abnormality detection unit 41, it transmits identification information of the abnormality detection unit 41 in which the abnormality was detected to the drive control unit 43. The drive control unit 43 turns off the transistor MN connected to the abnormality detection unit 41 in which the abnormality was detected. As a result, when an abnormality is detected in any of the abnormality detection units 41, it is possible to stop the second light source group connected to the abnormality detection unit 41 in which the abnormality was detected.

[0055] Furthermore, when the light emission control unit 42 identifies the second light source group caused by the abnormality from the second light source group in which the abnormality has occurred, it turns off the transistor MN connected to the second light source group caused by the abnormality via the drive control unit 43. The light emission control unit 42 can stop the light emission operation only for the second light source group in which the abnormality has been detected by the abnormality detection unit 41 and the second light source group caused by the abnormality. This allows the other second light source groups not involved in the abnormality to continue their light emission operation.

[0056] The light emission control unit 42 may be provided outside the light source device 1.

[0057] The drive control unit 43 controls the transistors MP and MN to select one or more light-emitting elements 30. Fig. 4 shows an example in which a signal from the drive control unit 43 is input to the gate of the transistor MN and also to one of the input terminals of the abnormality detection unit 41. A control line through which the drive control unit 43 controls the transistor MP is omitted in Fig. 4. Note that a drive control unit that controls the transistor MP may be provided separately from the drive control unit 43 that controls the transistor MN.

[0058] 5 is a diagram illustrating an example of an abnormality in the light source device 1. In the light source device 1 of FIG. 5, the drive control unit 43 detects the transistor MN k In this example, a high-level voltage is supplied to the gate of transistor MN, and a low-level voltage is supplied to the gates of the other transistors MN. A high-level voltage is also supplied to the gates of all the transistors MP. As a result, the k-th second light source group is selected from among the multiple second light source groups.

[0059] Also, the transistor MN k The abnormality detection unit 41 connected to the k-th transistor MN is set to a state in which the abnormality detection operation is stopped. The plurality of abnormality detection units 41 connected to the other transistors MN are set to a state in which the abnormality detection operation is performed. As a result, in the light source device 1 of FIG. 5, the second light source groups other than the k-th second light source group can detect an abnormality in the light-emitting element 30.

[0060] 5, the signal line connected to each cathode of the kth second light source group and the signal line connected to each cathode of the k+1th second light source group are short-circuited 51. Due to the short-circuit 51, the signal line connected to each cathode of the kth second light source group has the same voltage level as the signal line connected to each cathode of the k+1th second light source group.

[0061] Due to the short circuit 51, an abnormality occurs in which the cathode voltage of the light-emitting element 30b belonging to the k+1th second light source group instantaneously fluctuates due to the influence of a voltage change in the cathode voltage when the light-emitting element 30a belonging to the kth second light source group emits light.

[0062] This causes the transistor MN k+1 Even though the light emitting element 30b in the k+1-th second light source group is in the off state, the light emitting element 30b in the k+1-th second light source group may emit light. Or, the light amount of the light emitting element 30a in the k-th second light source group may decrease.

[0063] The abnormality detection unit 41 corresponding to the k+1th second light source group detects an abnormality in which the terminal voltage (i.e., the cathode voltage) of any of the light-emitting elements 30 included in the k+1th second light source group instantaneously fluctuates by more than the second voltage.

[0064] 5 shows an example in which the abnormality detection unit 41 detects a short circuit abnormality, but the abnormality detection unit 41 can also detect abnormalities other than a short circuit. As an abnormality other than a short circuit, for example, a possible abnormality is an abnormality in which the voltage level of a signal line that is not a light emitting target fluctuates due to interference caused by parasitic capacitance between a signal line connected to a selected second light source group and a signal line connected to a non-selected second light source group.

[0065] When the abnormality detection unit 41 detects an abnormality, the drive control unit 43 controls the selection unit not to select two or more light-emitting elements 30 caused by the abnormality among the multiple light-emitting elements 30. The two or more light-emitting elements 30 caused by the abnormality refer to the light-emitting element 30 that was not selected by the selection unit in which the abnormality was detected (i.e., the light-emitting element 30a in FIG. 5) and the light-emitting element 30 that was selected by the selection unit that caused the abnormality in the light-emitting element 30a (i.e., the light-emitting element 30b in FIG. 5). The light-emitting elements 30a and 30b caused by the abnormality constitute an abnormality group 52.

[0066] The drive control unit 43 controls the transistor MN so that the light emitting elements 30a and 30b belonging to the abnormal group 52 are not selected. Specifically, the drive control unit 43 controls the transistor MN k and M.N. k+1 Turn off the

[0067] The drive control unit 43 may cause the selection unit to select a light-emitting element 30 that is not caused by an abnormality (for example, the light-emitting element 30c belonging to the k-1th second light source group). By stopping the light-emitting operation of only the light-emitting elements 30a, 30b in which an abnormality has occurred, it becomes unnecessary to stop the light-emitting operation of all the light-emitting elements 30 in the light source device 1, and it is possible to effectively utilize the light source device 1 because it is not necessary to stop the light-emitting operation of all the light-emitting elements 30 due to an abnormality in some of the light-emitting elements 30 in the light source device 1. Note that the drive control unit 43 may stop the light emission of multiple light-emitting elements 30 in the light source device 1 when the abnormality detection unit 41 detects an abnormality.

[0068] 6A is a diagram showing a detailed configuration of the abnormality detection unit 41 according to an embodiment of the present disclosure. The abnormality detection unit 41 has a first circuit 60 and a second circuit .

[0069] The first circuit 60 is connected to at least one of the anode and cathode (cathode in the example of FIG. 6A) of the light-emitting element 30b not selected by the selection unit, and functions as a filter that blocks the DC component of the cathode voltage of the light-emitting element 30b and passes the AC component. The first circuit 60 has a capacitor 61 and a resistor (first resistor) 62.

[0070] One end of the capacitor 61 is connected to at least one of the anode and cathode (cathode in the example of FIG. 6A) of the light-emitting element 30b not selected by the selection unit. The capacitor 61 extracts an AC component from the cathode voltage of the light-emitting element 30b.

[0071] The capacitor 61 can separate the abnormality detection unit 41 in a DC (direct current) manner, and transmit only an AC (alternating current) signal to the second circuit 70. This allows the second circuit 70 to be configured with low-voltage elements and to operate under a low-voltage power supply. Therefore, the abnormality detection unit 41 can be configured with low power consumption and a small area, and material costs can be reduced.

[0072] The resistor 62 is connected to the other end of the capacitor 61. The resistor 62 functions as a high-pass filter that passes, out of the signals output from the capacitor 61, signals having a frequency equal to or higher than a predetermined frequency.

[0073] The second circuit 70 outputs an abnormality detection signal indicating that an abnormality has been detected, based on the output signal of the first circuit 60. The second circuit 70 includes inverters 71 and 72, and a flip-flop 73.

[0074] The inverter 71 is connected to the first circuit 60. The inverter 71 inverts the output signal of the first circuit 60 and inputs it to a clock input terminal of the flip-flop 73. The inverter 72 is connected to the gate of the transistor MN. The inverter 72 inverts the signal input to the gate of the transistor MN and inputs it to a reset terminal of the flip-flop 73.

[0075] The flip-flop 73 outputs the abnormality detection signal Err in synchronization with a change in the signal level of the output signal of the first circuit 60. An inverted signal of the output signal of the inverter 72 is input to the reset terminal of the flip-flop 73. When a high-level signal is input to the reset terminal, the flip-flop 73 is released from the reset state, and the abnormality detection signal Err can be output. The flip-flop 73 outputs the abnormality detection signal Err from the error output terminal at the timing when the output signal of the first circuit 60 input from the clock input terminal via the inverter 72 transitions from high level to low level. When a low-level signal is input to the reset terminal, the flip-flop 73 enters the reset state, and the high-level abnormality detection signal Err is reset to low level.

[0076] That is, when the corresponding transistor MN is in the on state, the flip-flop 73 is reset, and the abnormality detection unit 41 stops the abnormality detection operation. When the corresponding transistor MN is in the off state, the reset state of the flip-flop 73 is released, and the abnormality detection unit 41 performs the abnormality detection operation.

[0077] 6A shows transistor MNa in an on state, transistor MNb in an off state, light-emitting element 30a selected by transistor MNa, and light-emitting element 30b not selected by transistor MNb. A short circuit 51 has occurred between light-emitting elements 30a and 30b. Furthermore, abnormality detection unit 41 connected to transistor MNa is in a state where the abnormality detection operation has been stopped, and abnormality detection unit 41 connected to transistor MNb is in a state where the abnormality detection operation is being performed.

[0078] When the light-emitting element 30a emits light, the cathode voltage of the light-emitting element 30a drops instantaneously. The abnormality detection unit 41 connected to the transistor MNa has stopped the abnormality detection operation, so does not detect an abnormality even if the cathode voltage of the light-emitting element 30a drops. The short circuit 51 propagates the change in the cathode voltage of the light-emitting element 30a, causing the cathode voltage of the light-emitting element 30b to drop instantaneously. In the abnormality detection unit 41 connected to the transistor MNb, the first circuit 60 captures the high-frequency components of the signal based on the drop in the cathode voltage of the light-emitting element 30b into the flip-flop 73, and the abnormality detection signal Err is output.

[0079] 6A, the abnormality detection unit 41 stops the abnormality detection operation when the corresponding light-emitting element 30 is selected as the light-emitting target, thereby reducing power consumption. In addition, the abnormality detection unit 41 detects instantaneous voltage fluctuations of the light-emitting element 30 that is not selected as the light-emitting target, so that abnormalities can be detected with low power consumption.

[0080] FIG. 6B is a circuit diagram of a first modified example of the first circuit 60. The first circuit 60a shown in FIG. 6B has a resistor (second resistor) 63 in addition to the capacitor 61 and resistor 62 in FIG. 6A. The resistor 63 is connected between the cathode of the light-emitting element 30 and one end of the capacitor 61. The resistor 63 suppresses the amplitude of the signal transmitted to the second circuit 70. If the second circuit 70 is composed of low-voltage elements, it may break down if a signal with a large amplitude is transmitted from the light-emitting element 30. The resistor 63 can protect the second circuit 70 by adjusting the amplitude of the signal transmitted to the second circuit 70.

[0081] FIG. 6C is a circuit diagram of a second modified example of the first circuit 60. The first circuit 60b shown in FIG. 6C has an inductor 64 in addition to the capacitor 61 and resistor 62 in FIG. 6A. The inductor 64 is connected between the cathode of the light-emitting element 30 and one end of the capacitor 61. The inductor 64 allows the first circuit 60b to be used as a band-pass filter. This allows the first circuit 60b to cut noise of low and high frequency components and extract only signal components when a short circuit 51 (or interference) occurs between the cathodes of the light-emitting element 30. The first circuit 60b can cut noise particularly effectively when a steep voltage fluctuation is expected at the anode or cathode of the light-emitting element 30 during light emission. The first circuit 60b may have the resistor 63 in FIG. 6B.

[0082] Fig. 7 is a circuit diagram of a second configuration example of the light source device 1 according to an embodiment of the present disclosure. The light source device 1a shown in Fig. 7 differs from the light source device 1 of Fig. 4 in that an abnormality detection unit 81 is provided for each first light-emitting group on the transistor MP side. The light source device 1a of Fig. 7 detects, by the abnormality detection unit 41, a short circuit (or interference) abnormality occurring between a plurality of light-emitting elements 30 belonging to different second light source groups, and detects, by the abnormality detection unit 81, a short circuit (or interference) abnormality occurring between a plurality of light-emitting elements 30 belonging to different first light source groups.

[0083] The abnormality detection unit 81 has a first circuit 82 and a second circuit 83, similar to the abnormality detection unit 41. The first circuit 82 has a capacitor 91 and a resistor 92, similar to the first circuit 60 in FIG.

[0084] The drive control unit 43 controls the drive of the transistor MN based on the abnormality detected by the abnormality detection unit 41. The drive control unit 84 controls the drive of the transistor MP based on the abnormality detected by the abnormality detection unit 81. Note that the light emission control unit 42 is not shown in FIG. The drive control unit 84 may be included in the drive control unit 43.

[0085] In Fig. 7, the transistors MPa and MNa are on, and the transistors MPb and MNb are off. The light-emitting element 30d is selected as the light-emitting element by the transistors MPa and MNa. In the example of Fig. 7, a short circuit 51 occurs between the light-emitting element 30d and the light-emitting element 30e belonging to the second light source group corresponding to the transistor MNb. In the example of Fig. 7, a short circuit 85 occurs between the light-emitting element 30d and the light-emitting element 30f belonging to the first light source group corresponding to the transistor MPb.

[0086] The abnormality detection unit 41 connected to the transistor MNb detects a voltage change of either the anode or the cathode (cathode in the example of FIG. 7) of the light-emitting element 30e in response to a voltage change of either the anode or the cathode (cathode in the example of FIG. 7) when the light-emitting element 30d emits light. Based on the abnormality detected by the abnormality detection unit 41, the drive control unit 43 controls the transistor MN not to select the second light source group including the light-emitting element 30d that is the target for light emission and that has caused the abnormality, and the second light source group including the light-emitting element 30e in which the abnormality has been detected. More specifically, the drive control unit 43 turns off the transistors MNa and MNb.

[0087] The abnormality detection unit 81 corresponding to the transistor MPb detects a voltage change of the other of the anode or cathode (anode in the example of FIG. 7) of the light-emitting element 30f in response to a voltage change of the other of the anode or cathode (anode in the example of FIG. 7) when the light-emitting element 30d emits light. Based on the abnormality detected by the abnormality detection unit 81, the drive control unit 84 controls the transistor MP not to select the first light source group including the light-emitting element 30d that is the target for light emission and that has caused the abnormality, and the first light source group including the light-emitting element 30f in which the abnormality has been detected. More specifically, the drive control unit 84 turns off the transistors MPa and MPb.

[0088] As shown in Fig. 5, Fig. 7, etc., the light source device 1, 1a according to an embodiment of the present disclosure can detect two or more first light source groups (or two or more second light source groups) in which a short circuit abnormality or interference has occurred among the multiple first light source groups and the multiple second light source groups. Furthermore, the light source device 1, 1a excludes only the first light source group or the second light source group in which an abnormality has occurred from the multiple first light source groups and the multiple second light source groups from the light emission target, and allows the other light emitting elements to continue the light emission operation. This allows the light emitting device 1 to be effectively used even if an abnormality is detected in some of the light emitting elements.

[0089] Fig. 8 is a circuit diagram of light source device 100 used in a simulation to confirm the operation of abnormality detection unit 41. Light source device 100 in Fig. 8 has a switch SW for simulating a short-circuit abnormality. The switch SW is connected between the cathode of light-emitting element 30a to be emitted and the cathode of light-emitting element 30b to be not emitted. When switch SW is in an on state, it short-circuits the cathode of light-emitting element 30a and the cathode of light-emitting element 30b (i.e., equivalent to short circuit 51 in Fig. 5).

[0090] The transistor MPa that selects the light-emitting element 30a is driven by a driver drive pulse signal Pls that indicates the light emission timing. A voltage equal to or higher than a first voltage Von is applied between the anode and cathode of the light-emitting element 30a that is to be emitted in accordance with the light emission timing. On the other hand, when the switch SW is in the off state, the voltages of the anode and cathode of the light-emitting element 30b that is not to be emitted are set to a reference voltage Voff. When the voltage of at least one of the anode or cathode of the light-emitting element 30b instantaneously varies from the reference voltage Voff by a predetermined voltage or more (a second voltage described below), the abnormality detection unit 41 outputs an abnormality detection signal Err.

[0091] 9 is a timing chart of a plurality of signals input to and output from the light source device 100. The driver drive pulse signal Pls, which indicates the timing of light emission, temporarily goes high at a predetermined interval. For example, the driver drive pulse signal Pls temporarily goes high at each of times t1 and t2. As a result, the cathode voltage V30a of the light emitting element 30a temporarily goes lower than the first voltage Von at times t1 and t2.

[0092] At times t1 and t2, the switch SW is in the off state, and the cathode voltage V30b of the light-emitting element 30b hardly varies from the reference voltage Voff, so that the abnormality detection unit 41 does not output a high-level abnormality detection signal Err. In this way, when the light-emitting elements 30a and 30b are not short-circuited, the abnormality detection unit 41 does not output the abnormality detection signal Err.

[0093] At time t3, a high-level voltage is applied to the switch SW, turning the switch SW on, thereby shorting the light-emitting elements 30a and 30b.

[0094] The driver drive pulse signal Pls temporarily becomes high level at time t4 after time t3. As a result, the cathode voltage V30a of the light emitting element 30a temporarily becomes a voltage lower than the first voltage Von. Also, since the light emitting element 30b is short-circuited to the light emitting element 30a, the cathode voltage V30b of the light emitting element 30b becomes a voltage lower than the first voltage Von. Since the cathode voltage V30b fluctuates by the second voltage (Voff-Von) or more, the abnormality detection unit 41 stores an abnormality in the flip-flop 73 and outputs a high-level abnormality detection signal Err. In this way, the second voltage is the voltage difference (Voff-Von) between the cathode voltage (reference voltage Voff) of the light emitting element 30b when the transistor MP connected to the anode of the light emitting element 30b that is not to be emitted is off, and the cathode voltage (first voltage Von) of the light emitting element 30a when the transistor MP connected to the cathode of the light emitting element 30a that is to be emitted is on. The abnormality detection unit 41 outputs an abnormality detection signal Err when the cathode voltage of the light emitting element 30b fluctuates by a value equal to or greater than the second voltage (Voff-Von).

[0095] The driver drive pulse signal Pls becomes high level at time t5 after time t4. As a result, similar to the time t4, the cathode voltage V30a of the light-emitting element 30a and the cathode voltage V30b of the light-emitting element 30b become voltages lower than the first voltage Von. Since the abnormality detection unit 41 has already detected an abnormality at time t4, it continues to output the high-level abnormality detection signal Err.

[0096] 10 is a diagram illustrating a schematic configuration of a distance measuring system 2 according to an embodiment of the present disclosure. The distance measuring system 2 is a true-solid-state distance measuring system, and includes a light source device 1b and a light receiving device (SPAD) 105. The light source device 1b includes a vertical-cavity surface-emitting laser (VCSEL) 101 and a driver IC (Driver Integrated Circuit) 102.

[0097] The light emission timing of each light emitting element 30 of the VCSEL 101 in the light source device 1b is controlled by the driver IC 102, and each light emitting element 30 simultaneously or sequentially irradiates light onto the subject OBJ. More specifically, light from each light emitting element 30 is irradiated onto the subject OBJ via the light emission optical system 103. The light receiving device 105 receives reflected light from the subject OBJ via the light receiving optical system 104, and performs distance measurement processing to measure the distance to the subject OBJ. The driver IC 102 has, for example, the function of the light emission control unit 42 in FIG. 4. The VCSEL 101 has, for example, a plurality of light emitting elements 30. The light receiving device 105 has, for example, a pixel array unit 10.

[0098] The true-solid-state distance measuring system measures distance within the range of the laser irradiation angle emitted by the VCSEL 101 and transmitted through the light emission optical system 103. Compared to conventional MEMS distance measuring systems that expand the observation range by mechanically rotating a light source device and a light receiving device, the true-solid-state distance measuring system does not require any moving or rotating parts, and therefore has the advantages of being easily miniaturized, having a high degree of freedom in the installation location, being less likely to break, and being able to reduce manufacturing costs.

[0099] On the other hand, in a true-solid-state distance measuring system, since a complex light source device is required with densely packed light emitting elements, when an abnormality occurs, light emitting elements that are not the target for light emission may unexpectedly emit light, and the light emission intensity of the light output from the light source device may exceed the safety standard for laser light, which may cause damage to the human eye. Also, the light emission intensity of the target light source element may decrease, which may cause a decrease in distance measuring accuracy.

[0100] In the light source device 1 according to an embodiment of the present disclosure, an abnormal light emitting element is detected, and only the light emitting element group caused by the abnormality is stopped from emitting light, while the other light source groups continue emitting light. When the light source device 1 according to an embodiment of the present disclosure is applied to a true-solid-state distance measuring system, even if an abnormality occurs in the light source device 1, the light emitting element that is not the target for emitting light will not emit light, and the emission intensity of the light output from the light source device 1 will not exceed the safety standard for laser light, so eye safety can be ensured. In addition, the light source device 1 can continue distance measuring without deteriorating the distance measuring accuracy, because there is no risk of the emission intensity of the light source element that is the target for emitting light being reduced due to an abnormality.

[0101] Thus, the light source device 1 according to an embodiment of the present disclosure has an abnormality detection unit 41 that can detect, as an abnormality, an instantaneous voltage fluctuation in a plurality of light-emitting elements 30 that are not the target for light emission. By detecting an abnormality with the abnormality detection unit 41, the light source device 1 can detect an abnormality caused by a short circuit or interference between the light-emitting elements 30, and can stop the light emission operation of the light-emitting element 30 in which an abnormality has occurred. In other words, the light source device 1 according to an embodiment of the present disclosure can accurately detect an abnormality caused by a short circuit or interference between a plurality of light-emitting elements and suppress the effects thereof.

[0102] This makes it possible to prevent unintended emission of the light-emitting element 30 due to short circuit or interference, and to prevent a decrease in the amount of light of the light-emitting element 30 that is the target of emission. Furthermore, in the distance measurement system 2 to which the light source devices 1, 1a are applied, eye safety can be ensured and a decrease in distance measurement accuracy can be prevented even when the light source devices 1, 1a malfunction.

[0103] Furthermore, the abnormality detection unit 41 according to an embodiment of the present disclosure is DC-isolated from the light-emitting element 30 by the capacitor 61, and can detect AC signals. This allows the abnormality detection unit 41 to be configured with low-voltage elements, and allows for low power consumption and miniaturization.

[0104] (Application example) The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, a construction machine, an agricultural machine (tractor), etc.

[0105] 11 is a block diagram showing a schematic configuration example of a vehicle control system 7000 which is an example of a mobile object control system to which the technology according to the present disclosure can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected via a communication network 7010. In the example shown in FIG. 11, the vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an outside-vehicle information detection unit 7400, an inside-vehicle information detection unit 7500, and an integrated control unit 7600. The communication network 7010 connecting these multiple control units may be an in-vehicle communication network conforming to any standard such as CAN (Controller Area Network), LIN (Local Interconnect Network), LAN (Local Area Network), or FlexRay (registered trademark).

[0106] Each control unit includes a microcomputer that performs arithmetic processing according to various programs, a storage unit that stores the programs executed by the microcomputer or parameters used in various calculations, and a drive circuit that drives various control target devices. Each control unit includes a network I / F for communicating with other control units via a communication network 7010, and a communication I / F for communicating with devices or sensors inside and outside the vehicle by wired communication or wireless communication. In FIG. 11, a microcomputer 7610, a general-purpose communication I / F 7620, a dedicated communication I / F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F 7660, an audio / video output unit 7670, an in-vehicle network I / F 7680, and a storage unit 7690 are illustrated as the functional configuration of the integrated control unit 7600. Other control units also include a microcomputer, a communication I / F, a storage unit, and the like.

[0107] The drivetrain control unit 7100 controls the operation of devices related to the drivetrain of the vehicle according to various programs. For example, the drivetrain control unit 7100 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle. The drivetrain control unit 7100 may also function as a control device such as an ABS (Antilock Brake System) or an ESC (Electronic Stability Control).

[0108] A vehicle state detection unit 7110 is connected to the drive system control unit 7100. The vehicle state detection unit 7110 includes at least one of a gyro sensor that detects the angular velocity of the axial rotational motion of the vehicle body, an acceleration sensor that detects the acceleration of the vehicle, or a sensor for detecting the amount of operation of an accelerator pedal, the amount of operation of a brake pedal, the steering angle of a steering wheel, the engine rotation speed, or the rotation speed of wheels, for example. The drive system control unit 7100 performs arithmetic processing using signals input from the vehicle state detection unit 7110, and controls the internal combustion engine, the drive motor, the electric power steering device, the brake device, etc.

[0109] The body system control unit 7200 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as head lamps, back lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals of various switches transmitted from a portable device that replaces a key may be input to the body system control unit 7200. The body system control unit 7200 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, and the like of the vehicle.

[0110] The battery control unit 7300 controls the secondary battery 7310, which is a power supply source for the drive motor, according to various programs. For example, information such as battery temperature, battery output voltage, or remaining capacity of the battery is input to the battery control unit 7300 from a battery device equipped with the secondary battery 7310. The battery control unit 7300 performs calculation processing using these signals, and controls the temperature regulation of the secondary battery 7310 or controls a cooling device or the like equipped in the battery device.

[0111] The outside-vehicle information detection unit 7400 detects information outside the vehicle equipped with the vehicle control system 7000. For example, at least one of an imaging unit 7410 and an outside-vehicle information detection unit 7420 is connected to the outside-vehicle information detection unit 7400. The imaging unit 7410 includes at least one of a ToF (Time Of Flight) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The outside-vehicle information detection unit 7420 includes at least one of an environmental sensor for detecting the current weather or climate, or a surrounding information detection sensor for detecting other vehicles, obstacles, pedestrians, and the like around the vehicle equipped with the vehicle control system 7000.

[0112] The environmental sensor may be, for example, at least one of a raindrop sensor that detects rain, a fog sensor that detects fog, a sunshine sensor that detects the degree of sunshine, and a snow sensor that detects snowfall. The surrounding information detection sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) device. The imaging unit 7410 and the outside vehicle information detection unit 7420 may be provided as independent sensors or devices, or may be provided as a device in which multiple sensors or devices are integrated.

[0113] Here, FIG. 12 shows an example of the installation positions of the imaging unit 7410 and the vehicle exterior information detection unit 7420. The imaging units 7910, 7912, 7914, 7916, and 7918 are provided, for example, at least one of the front nose, side mirrors, rear bumper, back door, and upper part of the windshield in the vehicle interior of the vehicle 7900. The imaging unit 7910 provided on the front nose and the imaging unit 7918 provided on the upper part of the windshield in the vehicle interior mainly acquire images of the front of the vehicle 7900. The imaging units 7912 and 7914 provided on the side mirrors mainly acquire images of the sides of the vehicle 7900. The imaging unit 7916 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 7900. The imaging unit 7918 provided on the upper part of the windshield in the vehicle interior is mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

[0114] 12 shows an example of the imaging ranges of the imaging units 7910, 7912, 7914, and 7916. Imaging range a indicates the imaging range of the imaging unit 7910 provided on the front nose, imaging ranges b and c indicate the imaging ranges of the imaging units 7912 and 7914 provided on the side mirrors, and imaging range d indicates the imaging range of the imaging unit 7916 provided on the rear bumper or back door. For example, image data captured by the imaging units 7910, 7912, 7914, and 7916 are superimposed to obtain an overhead image of the vehicle 7900.

[0115] The outside information detection units 7920, 7922, 7924, 7926, 7928, and 7930 provided on the front, rear, sides, and corners of the vehicle 7900 and on the upper part of the windshield inside the vehicle cabin may be, for example, ultrasonic sensors or radar devices. The outside information detection units 7920, 7926, and 7930 provided on the front nose, rear bumper, back door, and on the upper part of the windshield inside the vehicle cabin of the vehicle 7900 may be, for example, LIDAR devices. These outside information detection units 7920 to 7930 are mainly used to detect preceding vehicles, pedestrians, obstacles, and the like.

[0116] Returning to FIG. 11, the description will be continued. The outside-vehicle information detection unit 7400 causes the imaging unit 7410 to capture an image outside the vehicle, and receives the captured image data. The outside-vehicle information detection unit 7400 also receives detection information from the outside-vehicle information detection unit 7420 connected thereto. When the outside-vehicle information detection unit 7420 is an ultrasonic sensor, a radar device, or a LIDAR device, the outside-vehicle information detection unit 7400 transmits ultrasonic waves or electromagnetic waves, and receives information on the received reflected waves. The outside-vehicle information detection unit 7400 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, or characters on the road surface, based on the received information. The outside-vehicle information detection unit 7400 may perform environment recognition processing for recognizing rainfall, fog, road surface conditions, and the like, based on the received information. The outside-vehicle information detection unit 7400 may calculate the distance to an object outside the vehicle based on the received information.

[0117] Furthermore, the outside vehicle information detection unit 7400 may perform image recognition processing or distance detection processing to recognize people, cars, obstacles, signs, or characters on the road surface, based on the received image data. The outside vehicle information detection unit 7400 may perform processing such as distortion correction or position adjustment on the received image data, and may generate an overhead image or a panoramic image by synthesizing image data captured by different imaging units 7410. The outside vehicle information detection unit 7400 may perform viewpoint conversion processing using image data captured by different imaging units 7410.

[0118] The in-vehicle information detection unit 7500 detects information inside the vehicle. For example, a driver state detection unit 7510 that detects the state of the driver is connected to the in-vehicle information detection unit 7500. The driver state detection unit 7510 may include a camera that captures an image of the driver, a biosensor that detects the bioinformation of the driver, or a microphone that collects sound in the vehicle cabin. The biosensor is provided, for example, on the seat or steering wheel, and detects the bioinformation of a passenger sitting in the seat or a driver gripping the steering wheel. The in-vehicle information detection unit 7500 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 7510, or may determine whether the driver is dozing. The in-vehicle information detection unit 7500 may perform processing such as noise canceling processing on the collected sound signal.

[0119] The integrated control unit 7600 controls the overall operation of the vehicle control system 7000 according to various programs. The input unit 7800 is connected to the integrated control unit 7600. The input unit 7800 is realized by a device that can be operated by an occupant to input, such as a touch panel, a button, a microphone, a switch, or a lever. Data obtained by voice recognition of a voice input by a microphone may be input to the integrated control unit 7600. The input unit 7800 may be, for example, a remote control device using infrared or other radio waves, or an externally connected device such as a mobile phone or a PDA (Personal Digital Assistant) that supports the operation of the vehicle control system 7000. The input unit 7800 may be, for example, a camera, in which case the occupant can input information by gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the occupant may be input. Furthermore, the input unit 7800 may include, for example, an input control circuit that generates an input signal based on information input by the occupant using the above-mentioned input unit 7800 and outputs the input signal to the integrated control unit 7600. A passenger or the like operates the input unit 7800 to input various data to the vehicle control system 7000 and to instruct processing operations.

[0120] The storage unit 7690 may include a ROM (Read Only Memory) that stores various programs executed by the microcomputer, and a RAM (Random Access Memory) that stores various parameters, calculation results, sensor values, etc. The storage unit 7690 may be realized by a magnetic storage device such as an HDD (Hard Disc Drive), a semiconductor storage device, an optical storage device, or a magneto-optical storage device, etc.

[0121] The general-purpose communication I / F 7620 is a general-purpose communication I / F that mediates communication between various devices present in the external environment 7750. The general-purpose communication I / F 7620 may implement a cellular communication protocol such as GSM (registered trademark), WiMAX (registered trademark), LTE (registered trademark) (Long Term Evolution) or LTE-Advanced (LTE-A), or other wireless communication protocols such as wireless LAN (also called Wi-Fi (registered trademark)) and Bluetooth (registered trademark). The general-purpose communication I / F 7620 may connect to a device (e.g., an application server or a control server) present on an external network (e.g., the Internet, a cloud network, or a carrier-specific network) via, for example, a base station or an access point. The general-purpose communication I / F 7620 may also connect to a terminal (e.g., a driver's, pedestrian's, or store's terminal, or a Machine Type Communication (MTC) terminal) present in the vicinity of the vehicle using, for example, a Peer To Peer (P2P) technology.

[0122] The dedicated communication I / F 7630 is a communication I / F that supports a communication protocol designed for use in a vehicle. The dedicated communication I / F 7630 may implement a standard protocol such as WAVE (Wireless Access in Vehicle Environment), which is a combination of a lower layer IEEE802.11p and a higher layer IEEE1609, DSRC (Dedicated Short Range Communications), or a cellular communication protocol. The dedicated communication I / F 7630 typically performs V2X communication, which is a concept including one or more of vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

[0123] The positioning unit 7640 performs positioning by receiving, for example, a GNSS signal from a Global Navigation Satellite System (GNSS) satellite (for example, a GPS signal from a Global Positioning System (GPS) satellite) and generates position information including the latitude, longitude, and altitude of the vehicle. The positioning unit 7640 may identify the current position by exchanging signals with a wireless access point, or may obtain position information from a terminal such as a mobile phone, PHS, or smartphone having a positioning function.

[0124] The beacon receiving unit 7650 receives, for example, radio waves or electromagnetic waves transmitted from radio stations or the like installed on the road, and acquires information such as the current location, congestion, road closure, required time, etc. The function of the beacon receiving unit 7650 may be included in the dedicated communication I / F 7630 described above.

[0125] The in-vehicle device I / F 7660 is a communication interface that mediates a connection between the microcomputer 7610 and various in-vehicle devices 7760 present in the vehicle. The in-vehicle device I / F 7660 may establish a wireless connection using a wireless communication protocol such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), or WUSB (Wireless USB). In addition, the in-vehicle device I / F 7660 may establish a wired connection such as a Universal Serial Bus (USB), a High-Definition Multimedia Interface (HDMI (registered trademark), or a Mobile High-definition Link (MHL)) via a connection terminal (and a cable, if necessary) not shown. The in-vehicle device 7760 may include, for example, at least one of a mobile device or a wearable device owned by a passenger, or an information device carried into or attached to the vehicle. The in-vehicle device 7760 may also include a navigation device that searches for a route to an arbitrary destination. The in-vehicle device I / F 7660 exchanges control signals or data signals with these in-vehicle devices 7760.

[0126] The in-vehicle network I / F 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I / F 7680 transmits and receives signals in accordance with a predetermined protocol supported by the communication network 7010.

[0127] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 according to various programs based on information acquired through at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. For example, the microcomputer 7610 may calculate a control target value of a driving force generating device, a steering mechanism, or a braking device based on the acquired information inside and outside the vehicle, and output a control command to the drive system control unit 7100. For example, the microcomputer 7610 may perform cooperative control for the purpose of realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc. In addition, the microcomputer 7610 may perform cooperative control for the purpose of autonomous driving, in which the vehicle travels autonomously without relying on driver operation, by controlling a driving force generating device, a steering mechanism, a braking device, etc. based on information acquired about the vehicle's surroundings.

[0128] The microcomputer 7610 may generate three-dimensional distance information between the vehicle and objects such as surrounding structures and people, and create local map information including peripheral information of the current position of the vehicle, based on information acquired via at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. The microcomputer 7610 may also predict dangers such as vehicle collisions, the approach of pedestrians, or entry into a closed road, based on the acquired information, and generate a warning signal. The warning signal may be, for example, a signal for generating a warning sound or turning on a warning lamp.

[0129] The audio / image output unit 7670 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle of information. In the example of FIG. 11, an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are illustrated as output devices. The display unit 7720 may include, for example, at least one of an on-board display and a head-up display. The display unit 7720 may have an AR (Augmented Reality) display function. The output device may be other devices such as headphones, a wearable device such as a glasses-type display worn by the passenger, a projector, or a lamp, other than these devices. When the output device is a display device, the display device visually displays the results obtained by various processes performed by the microcomputer 7610 or information received from other control units in various formats such as text, image, table, graph, etc. When the output device is an audio output device, the audio output device converts an audio signal consisting of reproduced audio data or acoustic data into an analog signal and audibly outputs it.

[0130] In the example shown in FIG. 11, at least two control units connected via the communication network 7010 may be integrated into one control unit. Alternatively, each control unit may be composed of multiple control units. Furthermore, the vehicle control system 7000 may include another control unit not shown. In the above description, some or all of the functions performed by any control unit may be provided by another control unit. In other words, as long as information is transmitted and received via the communication network 7010, a predetermined arithmetic processing may be performed by any control unit. Similarly, a sensor or device connected to any control unit may be connected to another control unit, and multiple control units may transmit and receive detection information to each other via the communication network 7010.

[0131] A computer program for realizing the light emission control unit 42 according to the present embodiment described with reference to FIG. 4 can be implemented in any control unit or the like. A computer-readable recording medium in which such a computer program is stored can also be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. The computer program may also be distributed, for example, via a network, without using a recording medium.

[0132] In the vehicle control system 7000 described above, the distance measuring system 2 according to this embodiment described with reference to Fig. 1 can be applied to the outside vehicle information detection unit 7400 and the imaging unit 7410 of the application example shown in Fig. 11. For example, the distance measuring unit 11 of the distance measuring system 2 corresponds to the outside vehicle information detection unit 7400. Also, the light source device 1 of the distance measuring system 2 corresponds to the imaging unit 7410. For example, the light source device 1 detects an abnormality in the light emitting element 30 and stops the light emitting operation, thereby ensuring eye safety during distance measuring by the imaging unit 7410 and preventing a decrease in distance measuring accuracy.

[0133] At least some of the components of the distance measuring system 2 described with reference to FIG. 1 may be realized by a plurality of control units of the vehicle control system 7000 shown in FIG.

[0134] The present technology can be configured as follows. (1) A plurality of light emitting elements arranged in at least a first direction; A selection unit that selects some of the light-emitting elements from the plurality of light-emitting elements as light-emitting targets; and an abnormality detection unit that detects an abnormality caused by an instantaneous change in a terminal voltage of a light-emitting element not selected by the selection unit among the plurality of light-emitting elements. Light source device. (2) The selection unit applies a voltage equal to or higher than a first voltage between an anode and a cathode of a light emitting element to be emitted, and prevents a voltage equal to or higher than the first voltage from being applied between an anode and a cathode of a light emitting element that is not to be emitted; the abnormality detection unit detects the abnormality in which a voltage of at least one of an anode or a cathode of a light-emitting element not selected by the selection unit instantaneously fluctuates by a second voltage or more. A light source device as described in (1). (3) The abnormality detection unit detects a short circuit between a light emitting element selected by the selection unit and a light emitting element not selected by the selection unit. A light source device as described in (1) or (2). (4) the abnormality detection unit detects that a voltage of at least one of the anode or cathode of the non-selected light-emitting element instantaneously fluctuates by the second voltage or more due to an influence of a voltage change of at least one of the anode or cathode of the light-emitting element selected by the selection unit. A light source device as described in (2). (5) the abnormality detection unit is a first circuit connected to at least one of an anode or a cathode of a light emitting element not selected by the selection unit, the first circuit blocking a DC component and passing an AC component; and a second circuit that outputs an abnormality detection signal indicating that the abnormality has been detected based on the output signal of the first circuit. A light source device according to any one of (2) to (4). (6) the first circuit has a capacitor connected to at least one of an anode or a cathode of a light-emitting element not selected by the selection unit; A light source device as described in (5). (7) the first circuit includes a high-pass filter having a first resistor connected to the capacitor and passing signals having a predetermined frequency or higher; A light source device as described in (6). (8) the first circuit includes a bandpass filter having an inductor and a first resistor connected to the capacitor, the bandpass filter passing signals in a predetermined frequency band; A light source device as described in (6). (9) the first circuit has a second resistor having one end connected to the capacitor and the other end connected to the anode or cathode of the light-emitting element; The second resistor suppresses the amplitude of a signal input from the anode or cathode of the light-emitting element. A light source device as described in (7) or (8). (10) the second circuit has a flip-flop that outputs the abnormality detection signal in synchronization with a change in the signal level of the output signal of the first circuit; A light source device according to any one of (5) to (9). (11) The plurality of light emitting elements are arranged in a first direction and a second direction intersecting each other, and a first light source group including two or more light emitting elements arranged in the first direction is arranged in a plurality of pieces in the second direction, and a second light source group including two or more light emitting elements arranged in the second direction is arranged in a plurality of pieces in the first direction, The selection unit is a plurality of first selectors that select whether or not to apply a first potential to each of the plurality of first light source groups arranged in the second direction; a plurality of second selectors that select whether or not to apply a second potential to each of the plurality of second light source groups arranged in the first direction; The abnormality detection unit includes a plurality of abnormality detectors connected to at least one of a plurality of first light source groups arranged in the second direction or a plurality of second light source groups arranged in the first direction. A light source device according to any one of (1) to (10). (12) the first potential is applied to the anodes of two or more light-emitting elements included in the first light source group selected by the plurality of first selectors; The second potential is applied to cathodes of two or more light-emitting elements included in the second light source group selected by the second selectors. A light source device as described in (11). (13) a drive control unit configured to control the selection unit not to select at least two or more light-emitting elements caused by the abnormality among the plurality of light-emitting elements when the abnormality detection unit detects the abnormality, A light source device according to (11) or (12). (14) The drive control unit controls the selection unit not to select a light-emitting element not selected by the selection unit in which the abnormality was detected and a light-emitting element selected by the selection unit that caused the abnormality in the light-emitting element. A light source device as described in (13). (15) The drive control unit causes the selection unit to select a light emitting element not caused by the abnormality from among the plurality of light emitting elements. A light source device according to (13) or (14). (16) The drive control unit stops light emission of the plurality of light-emitting elements when the abnormality detection unit detects the abnormality. A light source device as described in (13). (17) When the abnormality is detected in any of the light-emitting elements included in any of the first light source groups among the plurality of first light source groups, the drive control unit controls the selection unit not to select a first light source group including a light-emitting element that is a light-emitting target that caused the abnormality and a first light source group including a light-emitting element in which the abnormality was detected. A light source device according to any one of (13) to (16). (18) When the abnormality is detected in any of the light-emitting elements included in any of the second light source groups among the plurality of second light source groups, the drive control unit controls the selection unit not to select a second light source group including a light-emitting element that is a light-emitting target that caused the abnormality and a second light source group including a light-emitting element in which the abnormality was detected. A light source device according to any one of (13) to (17). (19) a light emission control unit that specifies a light emission sequence of the plurality of light emitting elements; The abnormality detection unit notifies the light emission control unit of the detected abnormality. A light source device according to any one of (1) to (18). (20) a light source device having a plurality of light emitting elements arranged in at least a first direction; a light receiving section having a plurality of light receiving elements that receive light emitted by the plurality of light emitting elements and reflected by an object; a distance measuring unit that measures a distance to the object based on light emitted by the plurality of light emitting elements and reflected light received by the light receiving unit, The light source device includes: A selection unit that selects some of the light-emitting elements from the plurality of light-emitting elements as light-emitting targets; an abnormality detection unit that detects an abnormality caused by an instantaneous change in a terminal voltage of a light-emitting element not selected by the selection unit among the plurality of light-emitting elements, Ranging system.

[0135] The aspects of the present disclosure are not limited to the above-mentioned individual embodiments, but include various modifications that may be conceived by a person skilled in the art, and the effects of the present disclosure are not limited to the above-mentioned contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and intent of the present disclosure derived from the contents defined in the claims and their equivalents. [Explanation of symbols]

[0136] 1, 1a, 1b, 100 light source device, 2 distance measurement system, 3 distance measurement device, 4 overall control unit, 10 pixel array unit, 10a light receiving element, 11 distance measurement unit, 12 signal processing unit, 12a distance calculation unit, 13 control unit, 14 clock generation unit, 15 light source control unit, 16 drive circuit, 17 time digital converter, 18 histogram generation unit, 19 distance measurement control unit, 21 first chip, 22 second chip, 30, 30a, 30b, 30c, 30d, 30e, 30f light emitting element, 31, 32 substrate, 33 laminated film, 34, 36 pad, 35 common electrode, 37 bonding layer, 41 abnormality detection unit, 42 light emission control unit, 43, 84 drive control unit, 51, 85 short circuit, 52 abnormality group, 60, 60a, 60b, 82 First circuit, 61, 91 Capacitor, 62, 63, 92 Resistor, 64 Inductor, 70, 83 Second circuit, 71, 72 Inverter, 73, 93 Flip-flop, 81 Abnormality detection section, 101 VCSEL, 102 Driver IC, 103 Light emission optical system, 104 Light receiving optical system, 105 Light receiving device

Claims

1. A plurality of light emitting elements arranged in at least a first direction; A selection unit that selects some of the light-emitting elements from the plurality of light-emitting elements as light-emitting targets; and an abnormality detection unit that detects an abnormality caused by an instantaneous change in a terminal voltage of a light-emitting element not selected by the selection unit among the plurality of light-emitting elements. Light source device.

2. The selection unit applies a voltage equal to or greater than a first voltage between an anode and a cathode of a light-emitting element to be emitted, and prevents a voltage equal to or greater than the first voltage from being applied between an anode and a cathode of a light-emitting element that is not to be emitted; the abnormality detection unit detects the abnormality in which a voltage of at least one of an anode or a cathode of a light-emitting element not selected by the selection unit instantaneously fluctuates by a second voltage or more. The light source device according to claim 1 .

3. The abnormality detection unit detects a short circuit between a light emitting element selected by the selection unit and a light emitting element not selected by the selection unit. The light source device according to claim 1 .

4. the abnormality detection unit detects that a voltage of at least one of the anode or cathode of the non-selected light-emitting element instantaneously fluctuates by the second voltage or more due to an influence of a voltage change of at least one of the anode or cathode of the light-emitting element selected by the selection unit. The light source device according to claim 2 .

5. the abnormality detection unit is a first circuit connected to at least one of an anode or a cathode of a light emitting element not selected by the selection unit, the first circuit blocking a DC component and passing an AC component; a second circuit that outputs an abnormality detection signal indicating that the abnormality has been detected based on the output signal of the first circuit. The light source device according to claim 2 .

6. the first circuit has a capacitor connected to at least one of an anode or a cathode of a light-emitting element not selected by the selection unit; The light source device according to claim 5 .

7. the first circuit includes a high-pass filter having a first resistor connected to the capacitor and passing signals having a predetermined frequency or higher; The light source device according to claim 6 .

8. the first circuit includes a bandpass filter having an inductor and a first resistor connected to the capacitor, the bandpass filter passing a signal in a predetermined frequency band; The light source device according to claim 6 .

9. the first circuit has a second resistor having one end connected to the capacitor and the other end connected to the anode or cathode of the light-emitting element; The second resistor suppresses the amplitude of a signal input from the anode or cathode of the light-emitting element. The light source device according to claim 7.

10. the second circuit has a flip-flop that outputs the abnormality detection signal in synchronization with a change in the signal level of the output signal of the first circuit; The light source device according to claim 5 .

11. The plurality of light emitting elements are arranged in a first direction and a second direction intersecting each other, and a first light source group including two or more light emitting elements arranged in the first direction is arranged in a plurality of pieces in the second direction, and a second light source group including two or more light emitting elements arranged in the second direction is arranged in a plurality of pieces in the first direction, The selection unit is a plurality of first selectors that select whether or not to apply a first potential to each of the plurality of first light source groups arranged in the second direction; a plurality of second selectors that select whether or not to apply a second potential to each of the plurality of second light source groups arranged in the first direction; The abnormality detection unit includes a plurality of abnormality detectors connected to at least one of a plurality of first light source groups arranged in the second direction or a plurality of second light source groups arranged in the first direction. The light source device according to claim 1 .

12. the first potential is applied to the anodes of two or more light-emitting elements included in the first light source group selected by the first selectors; the second potential is applied to cathodes of two or more light-emitting elements included in the second light source group selected by the second selectors; The light source device according to claim 11.

13. a drive control unit configured to control the selection unit not to select at least two or more light-emitting elements caused by the abnormality among the plurality of light-emitting elements when the abnormality detection unit detects the abnormality, The light source device according to claim 11.

14. The drive control unit controls the selection unit not to select a light-emitting element not selected by the selection unit in which the abnormality was detected and a light-emitting element selected by the selection unit that caused the abnormality in the light-emitting element. The light source device according to claim 13.

15. The drive control unit causes the selection unit to select a light emitting element not caused by the abnormality from among the plurality of light emitting elements. The light source device according to claim 13.

16. The drive control unit stops light emission of the plurality of light-emitting elements when the abnormality detection unit detects the abnormality. The light source device according to claim 13.

17. When the abnormality is detected in any of the light-emitting elements included in any of the first light source groups among the plurality of first light source groups, the drive control unit controls the selection unit not to select a first light source group including a light-emitting element that is a light-emitting target that caused the abnormality and a first light source group including a light-emitting element in which the abnormality was detected. The light source device according to claim 13.

18. When the abnormality is detected in any of the light-emitting elements included in any of the second light source groups among the plurality of second light source groups, the drive control unit controls the selection unit not to select a second light source group including a light-emitting element that is a light-emitting target that caused the abnormality and a second light source group including a light-emitting element in which the abnormality was detected. The light source device according to claim 13.

19. a light emission control unit that specifies a light emission sequence of the plurality of light emitting elements; The abnormality detection unit notifies the light emission control unit of the detected abnormality. The light source device according to claim 1 .

20. a light source device having a plurality of light emitting elements arranged in at least a first direction; a light receiving section having a plurality of light receiving elements that receive light emitted by the plurality of light emitting elements and reflected by an object; a distance measuring unit that measures a distance to the object based on light emitted by the plurality of light emitting elements and reflected light received by the light receiving unit, The light source device is A selection unit that selects some of the light-emitting elements from the plurality of light-emitting elements as light-emitting targets; an abnormality detection unit that detects an abnormality caused by an instantaneous change in a terminal voltage of a light-emitting element not selected by the selection unit among the plurality of light-emitting elements, Ranging system.

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