JP6590444B2 - Object detection device - Google Patents

Description

  The present invention relates to an object detection apparatus that detects an object based on a result of projecting light from a laser diode and receiving light reflected by a light receiving element.

  For example, an object detection device such as a vehicle-mounted laser radar projects light from a laser diode that is a light source, and detects the presence or absence of an object based on a result of receiving the reflected light by a light receiving element. There is also an object detection device that detects a distance to an object based on a time from emitting light from a laser diode to receiving reflected light from the object by a light receiving element.

  In order to expand the detection range of an object or improve the detection accuracy, the on-vehicle laser radar devices described in Patent Documents 1 to 3 use a plurality of laser diodes as light sources. Moreover, also in apparatuses in fields other than vehicles such as Patent Documents 4 to 6, a plurality of laser diodes are used as light sources. In Patent Document 2, a power storage unit (capacitor) that stores energy for causing each laser diode to emit light is provided on a one-to-one basis for each of a plurality of laser diodes.

JP 2010-151958 A Japanese Patent Laid-Open No. 7-167958 JP 7-183621 A JP 2002-76504 A JP 2002-267967 A JP 2012-69505 A

  When the power storage unit is connected to a plurality of laser diodes on a one-to-one basis as in the prior art, the number of parts in the power storage unit and its periphery increases, and the electrical circuit becomes complicated. On the other hand, when power is sequentially supplied to a plurality of laser diodes from a common (for example, a single) power storage unit, after one laser diode emits light with the power of the power storage unit, the power storage unit is not charged. The next laser diode cannot emit light, and the light emission period (light emission interval) becomes longer.

  The subject of this invention is providing the object detection apparatus which can implement | achieve simplification of an electric circuit and shortening of a light emission period.

  An object detection apparatus according to the present invention includes a plurality of laser diodes, a power storage unit that is a power source of the laser diode, a light emission selection unit for selecting a laser diode to emit light from the plurality of laser diodes, and a laser diode. The light receiving element that receives the reflected light from the object of the emitted light, the charging of the power storage unit, and the light emission of the laser diode selected by the light emission selecting unit are repeated, and the object is based on the light reception signal output from the light receiving element And a control unit for detecting. A plurality of laser diode modules each including a plurality of laser diodes, a light emission selection unit, and a power storage unit common to the plurality of laser diodes are provided, and one of the plurality of laser diode modules is one of the laser diode modules. The light emission operation of the diode is performed within the non-light emission period of the laser diode in the other laser diode module.

  According to the above, a laser diode module is composed of a plurality of laser diodes, a light emission selection unit, and a common power storage unit. For this reason, by supplying electric power from a common (for example, single) power storage unit to the laser diode selected by the light emission selection unit and causing the laser diode to emit light sequentially, the number of parts in the power storage unit and the surrounding area can be reduced. The electric circuit can be simplified. Also, a plurality of laser diode modules are provided, and one of the laser diode modules emits light during the non-light emission period of the laser diode in the other laser diode module. For this reason, for example, since the power storage unit is charged in the other laser diode module, even if the laser diode cannot emit light, one of the laser diodes is powered by the power of the power storage unit in one laser diode module. Can emit light. In other words, when the light emitting operation is performed by one laser diode module, the other laser diode module can perform the charging operation, so that the light emitting cycle can be shortened as the object detecting device.

  In the present invention, in each laser diode module, one laser diode may be able to emit light by electric power stored in the power storage unit by one charge.

  In the present invention, the light emitting operation of one of the laser diodes in one laser diode module may be performed within the charging period of the power storage unit in the other laser diode module.

  Further, in the present invention, in each laser diode module, the charging period of the power storage unit is set longer than the light emitting period of each laser diode, and after the charging of the power storage unit is completed, the light emitting operation of any laser diode is started immediately. Also good.

  Further, in the present invention, charging of the power storage unit in the other laser diode module may be started during the charging period of the power storage unit in one laser diode module.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the object detection apparatus which can implement | achieve simplification of an electrical circuit and shortening of a light emission period.

It is an electrical block diagram of the object detection apparatus by embodiment of this invention. It is a circuit block diagram of LD (laser diode) module of FIG. It is a circuit block diagram of PD (photodiode) module of FIG. It is the figure which showed the external appearance of the object detection apparatus of FIG. It is the perspective view which showed the optical system with which the inside of the object detection apparatus of FIG. 1 was equipped. It is the figure which showed the detail of LD module of FIG. FIG. 6 is an enlarged perspective view of the LD module and the projection lens of FIG. 5. It is the figure which showed the operation timing of LD module and PD module of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  First, an electrical configuration of the object detection apparatus 100 according to the embodiment will be described with reference to FIGS.

  FIG. 1 is an electrical configuration diagram of the object detection apparatus 100. The object detection device 100 is an on-vehicle laser radar. The control unit 1 includes a CPU and the like, and controls the operation of each unit of the object detection device 100.

  Two LD (laser diode) modules 2A and 2B are provided. Each LD module 2A, 2B is packaged. Each LD module 2A, 2B includes an LD (laser diode), a capacitor, and a switching element.

FIG. 2 is a circuit configuration diagram of the LD modules 2A and 2B. The LD module 2A is provided with four LD _A-1 , LD _A-2 , LD _A-3 , and LD _A-4 . The LD module 2B is provided with four LD _B-1 , LD _B-2 , LD _B-3 , and LD _B-4 . Each of these LDs is a light source that emits a high output light pulse. The LD module _2A, capacitor _{C A} common (single) is provided as a power source relative to _{LD A-1, LD A-} 2, LD A-3, LD A-4. In the LD module 2B, a common (single) capacitor C _B is provided as a power source for LD _B-1 , LD _B-2 , LD _B-3 , and LD _B-4 . The capacitors C _A and C _B are examples of the “power storage unit” in the present invention.

The LD module 2A includes four switching elements Q _A-1 and Q _A-2 so as to correspond to the _four LD _A-1 , LD _A-2 , LD _A-3 and LD _A-4 on a one-to-one basis. , Q _A-3 and Q _A-4 are provided. The LD module 2B includes four switching elements Q _B-1 and Q _B-2 so as to correspond to the _four LD _B-1 , LD _B-2 , LD _B-3 , and LD _B-4 on a one-to-one basis. , Q _B-3 and Q _B-4 are provided. Each switching element Q is composed of a MOS-FET.

The source of each switching element Q is connected to the anode of the corresponding LD. The drain of each switching element Q is connected to one end of capacitors C _A and C _B. One end of the capacitor _{C A} is connected to a power supply terminal _{V LD1} included in the charging circuit 3 (Figure 1). One end of the capacitor C _B is connected to a power supply terminal V _LD2 included in the charging circuit 3. The power supply terminal V _LD1 and the power supply terminal V _LD2 are independent, and the capacitors C _A and C _B of the respective LD modules 2A and 2B are individually charged from the respective power supply terminals V _LD1 and V _LD2 . That is, the charging circuit 3 of FIG. 1 includes two independent charging systems. The other ends of the capacitors C _A and C _B are grounded. The cathode of each LD is also grounded. The gate of each switching element Q is connected to the control unit 1 in FIG. 1 (not shown).

When the ON signal is input from the control unit 1 to the gate of each switching element Q (FIG. 2), each switching element Q is turned on, and current flows from the capacitors C _A and C _B to the corresponding LD, and the LD Emits light. The control unit 1 selects the LD that emits light by turning each switching element Q on and off. The switching element Q is an example of the “light emission selection unit” in the present invention.

The charging circuit 3 of FIG. 1 charges the capacitors C _A and C _B (FIG. 2) of the LD modules 2A and 2B. The power stored in the capacitor C _A a single charge by the charging circuit 3, one LD of the LD module 2A is capable of emitting light. The power stored in the capacitor C _B a single charge by the charging circuit 3, one LD of the LD module 2B is capable of emitting light. The control unit 1 causes each LD of the LD modules 2A and 2B to emit light and projects light onto a target such as a person or an object.

  The motor 4c in FIG. 1 is a drive source for an optical deflector 4 (FIG. 5 and the like) described later. The motor drive circuit 5 drives and rotates the motor 4c. The encoder 6 detects the rotational state (angle, rotational speed, etc.) of the motor 4c. The control unit 1 controls the operation of the optical deflector 4 by rotating the motor 4 c by the motor drive circuit 5. Further, the control unit 1 detects the operation state (operation amount, operation position, etc.) of the optical deflector 4 based on the output of the encoder 6.

  The PD (photodiode) module 7 is packaged. The PD module 7 includes a PD, a TIA (transimpedance amplifier), a MUX (multiplexer), and a VGA (variable gain amplifier).

FIG. 3 is a circuit configuration diagram of the PD module 7. The PD module 7 is provided with ₃₂ PD ₁ to PD ₃₂ and TIA ₁ to TIA ₃₂ , respectively. In FIG. 3, illustration of PD _{2 to} PD ₃₁ and TIA ₂ to TIA ₃₁ is omitted. PD _{1 to} PD ₃₂ and TIA ₁ to TIA ₃₂ are provided in a one-to-one correspondence.

Each of PD _{1 to} PD ₃₂ is a light receiving element formed of an avalanche photodiode. The anodes of the PD _{1 to} PD ₃₂ are connected to the power supply terminal V _PD of the booster circuit 9 in FIG. The cathode of each PD _{1 to} PD ₃₂ is connected to the input end of the corresponding TIA ₁ to TIA ₃₂ . Each of the TIA _{1 to} TIA ₃₂ is connected in parallel with a resistor (not shown). Each TIA _{1 to} TIA ₃₂ converts a current signal output from the corresponding PD ₁ to PD ₃₂ into a voltage signal.

The output end of each TIA ₁ -TIA ₃₂ is connected to a single MUX. Also, four VGA ₁ to VGA ₄ input terminals are connected to the MUX. Each of the VGA _{1 to} VGA ₄ is connected in parallel with a resistor (not shown). The output terminals of the VGA _{1 to} VGA ₄ are connected to the input terminals of _four ADCs (analog / digital converters) 8 _{1 to} ADC 8 ₄ , respectively. The output ends of the ADCs 8 _{1 to} ADC 8 ₄ are connected to the control unit 1 in FIG.

  The MUX controls the operation of each part of the PD, TIA, and VGA, and processes the voltage signal input from each TIA. Each VGA amplifies the signal output from the MUX. Each ADC 8 converts an analog signal output from each VGA into a digital signal and outputs the digital signal to the control unit 1. The booster circuit 9 in FIG. 1 supplies a boosted voltage necessary for the operation of the photodiode to each PD of the PD module 7.

  The control unit 1 causes the LD of the LD modules 2 </ b> A and 2 </ b> B to emit light so that the light reflected by the object is received by the PD of the PD module 7. Then, the control unit 1 processes the light reception signal output from the PD according to the light reception state by the TIA and VGA of the PD module 7. Further, the control unit 1 converts the analog light reception signal output from the PD module 7 into a digital light reception signal by the ADC 8, and detects the presence or absence of an object based on the digital light reception signal. Further, the control unit 1 emits light from the LD, calculates the time until the reflected light from the object is received by the PD, and detects the distance to the object based on the time.

  The storage unit 10 includes a volatile or nonvolatile memory. The storage unit 10 stores information for the control unit 1 to control each unit of the object detection device 100, information for detecting an object, and the like. The interface 11 includes a communication circuit such as Ethernet (registered trademark). The control part 1 transmits / receives the information regarding a target object with respect to ECU (electronic control apparatus) mounted in the vehicle by the interface 11, and transmits / receives various control information.

  Next, the structure and function of the object detection apparatus 100 will be described with reference to FIGS.

  FIG. 4 is a perspective view showing the appearance of the object detection apparatus 100. FIG. 5 is a perspective view showing an optical system provided in the object detection apparatus 100.

  As shown in FIG. 5, the case 12 of the object detection device 100 is a box having a rectangular shape when viewed from the front. The opening 12a of the case 12 is covered with a translucent cover 13 as shown in FIG. The translucent cover 13 is formed in a dome shape having a predetermined thickness.

  The internal space surrounded by the case 12 and the translucent cover 13 accommodates the optical system of the object detection apparatus 100 as shown in FIG. 5 and the electrical system of the object detection apparatus 100 shown in FIG. 5, the electrical system is not shown). The translucent cover 13 in FIG. 4 transmits light to the inside and outside of the case 12.

  The object detection device 100 is installed at the front, rear, or left and right sides of the vehicle, for example, so that the translucent cover 13 faces the front, rear, or left and right sides of the vehicle. At that time, as shown in FIG. 5, the object detection device 100 is installed in the vehicle so that the short side direction of the case 12 faces the vertical direction Z.

  As shown in FIG. 5, the optical system housed in the internal space such as the case 12 includes the LD modules 2A and 2B, the light projecting lenses 14A and 14B, the light deflector 4, the reflection mirrors 15 and 17, the light receiving lens 16, and It consists of a PD module 7.

  Among them, the LD modules 2A and 2B, the light projecting lenses 14A and 14B, and the optical deflector 4 are projection optical systems. The light deflector 4, the reflection mirrors 15 and 17, the light receiving lens 16, and the PD module 7 are light receiving optical systems.

  FIG. 6 is a diagram showing details of the LD modules 2A and 2B. In FIG. 6, the enlarged view of F section shown to (a) is shown to (b).

  As shown in FIG. 6A and the like, each of the LD modules 2A and 2B is formed in a thin rectangular parallelepiped shape. On one side surface 2c of each LD module 2A, 2B, as shown in FIG. 6B, the light emitting portions of four LDs are arranged in a line in the vertical direction Z. Each LD spreads in the first direction (vertical direction) Z at a first angle θ1 and spreads in a second direction Y perpendicular to the first direction Z at a second angle θ2 wider than the first angle θ1. (High output light pulse).

  FIG. 7 is an enlarged perspective view of the LD modules 2A and 2B and the projection lenses 14A and 14B shown in FIG. The LD modules 2A and 2B are separately mounted on both surfaces of a single substrate 21. Specifically, the LD module 2A is mounted on the front surface (the opening 12a side of the case 12) 21a of the substrate 21, and the LD module 2B is mounted on the back surface (the inner back side of the case 12) 21b of the substrate 21.

  One side surface 2c of each LD module 2A, 2B exposing the light emitting portion of the LD is flush with one side surface 21c of the substrate 21. As a result, the light emitted from the LDs of the LD modules 2A and 2B is not blocked by the substrate 21.

  As shown in FIG. 5, the substrate 21 has a boundary line between the front surface 21a of the substrate 21 and one side surface 2c of the LD module 2A, and a boundary line between the back surface 21b of the substrate 21 and one side surface 2c of the LD module 2B. It is fixed in the case 12 so as to be in the direction (first direction Z). The LDs of the LD modules 2A and 2B are arranged in the first direction Z. The LD modules 2A and 2B are arranged in the second direction Y with the substrate 21 interposed therebetween. Further, the LD module 2B is disposed above the LD module 2A and disposed on the inner back side of the case 12. The light emitting portions of the LDs of the LD modules 2A and 2B are similarly arranged.

  In front of the LD modules 2A and 2B (light emission direction X side), light projecting lenses 14A and 14B are arranged corresponding to the LD modules 2A and 2B. The projection lenses 14A and 14B adjust the spread of light emitted from the LDs of the LD modules 2A and 2B.

  The spread of the light emitted from each LD of the LD module 2A is adjusted by the light projection lens 14A. Further, the spread of the light emitted from each LD of the LD module 2B is adjusted by the light projecting lens 14B.

  The optical deflector 4 shown in FIG. 5 includes a motor 4c, a light projecting mirror 4a, and a light receiving mirror 4b. The motor 4 c is mounted on the substrate 22. The light projecting mirror 4a and the light receiving mirror 4b are composed of double-sided mirrors.

  The substrate 22 is fixed in the case 12 so that the rotating shaft (not shown) of the motor 4c is parallel to the Z direction. A light projecting mirror 4a is connected to one end (upper end in FIG. 5) of the rotating shaft of the motor 4c. A light receiving mirror 4b is connected to the other end of the rotating shaft of the motor 4c (the lower end in FIG. 5). For this reason, each mirror 4a, 4b rotates in conjunction with the rotating shaft of the motor 4c.

  As indicated by a short dashed line arrow in FIG. 5, the light emitted from the LD of the LD module 2 </ b> A is deflected by the light projecting lens 14 </ b> A and then deflected by the light projecting mirror 4 a of the light deflector 4. Then, the light passes through the translucent cover 13 (FIG. 4) and is irradiated onto the object. Further, as shown by a long dashed line arrow in FIG. 5, the light emitted from the LD of the LD module 2B is adjusted for spreading by the light projecting lens 14B, then deflected by the light projecting mirror 4a, and transmitted. The light passes through the light cover 13 and is irradiated onto the object.

  At that time, the motor 4c rotates to change the angle (direction) of the light projection mirror 4a, so that the light emitted from the LD is at a predetermined angle in the XY plane (horizontal plane) outside the translucent cover 13. It is scanned in the range. Further, the light emitted from the LD of the LD module 2A is projected in a range of a predetermined angle on the lower side (ground side) from the XY plane to which the reference point of the translucent cover 13 belongs. The light emitted from the LD of the LD module 2B is projected in a range of a predetermined angle on the upper side (empty side) from the XY plane to which the reference point of the translucent cover 13 belongs.

  A reflection mirror 15 is disposed below the substrate 21 in the vicinity of the opening 12 a of the case 12. A light receiving lens 16 and a reflection mirror 17 are arranged in this order in the interior of the case 12 so as to line up with the reflection mirror 15 in the Y direction. The light receiving lens 16 includes a condenser lens. The reflection mirrors 15 and 17 and the light receiving lens 16 are fixed to the case 12.

  In addition, a substrate 23 is disposed inward of the optical deflector 4 in the case 12. The substrate 23 is fixed to the case 12. The PD module 7 is mounted on the plate surface of the substrate 23 facing the reflection mirror 17 side. The PD module 7 includes the PD described above (FIG. 1).

  As described above, the light projected by the projection optical systems 2A, 2B, 14A, 14B, 4, 4a and transmitted through the translucent cover 13 is reflected by an object such as a person or an object. Then, the reflected light is transmitted through the translucent cover 13, and then reflected by the light receiving mirror 4b of the optical deflector 4 and further reflected by the reflecting mirror 15, as shown by the two-dot chain arrow in FIG. The light enters the light receiving lens 16. At this time, the motor 4c rotates to change the angle (orientation) of the light receiving mirror 4b, so that the reflected light from the object is within a predetermined angle range in the XY plane (horizontal plane) outside the translucent cover 13. Light is received by the light receiving mirror 4b.

  The reflected light that has entered the light receiving lens 16 via the mirrors 4b and 15 is collected by the light receiving lens 16 and then reflected by the reflecting mirror 17, as indicated by the dashed arrows in FIG. Is received by the PD. Then, after the light reception signal output from the PD according to the light reception state is processed by the PD module 7 or the ADC 8, the control unit 1 detects the presence or absence of the object based on the light reception signal, Or calculate the distance to.

  Next, the correspondence between the LD modules 2A and 2B of the object detection apparatus 100 and the PD module 7 and the operation timing will be described with reference to FIG.

FIG. 8 is a diagram showing the operation timing of the LD modules 2A and 2B and the PD module 7. In FIG. 8, the horizontal direction represents time, and the vertical direction represents each element. The rectangle of the diagonal grid represents the period during which the capacitors C _A and C _B are charged. The rectangles with right-down diagonal lines represent periods in which the laser diodes LD _{A-1 to} LD _{A- 4} and LD _{B-1 to} LD _B-4 perform the light emission operation. The rectangle in the upper right diagonal line represents the period during which the photodiodes PD _{1 to} PD ₃₂ perform the light receiving operation.

The reflected light of the light emitted from LD _B-1 of LD module 2B is received by PD ₁ and PD ₂ of PD module 7. In addition, the reflected light of the light emitted from the LD _B-2 is received by the PD ₃ and the PD ₄ . The reflected light of the light emitted from the LD _B-3 is received by the PD ₅ and the PD ₆ . Furthermore, the reflected light of the light emitted from the LD _B-4 is received by the PD _{7 to} PD ₁₂ .

The reflected light of the light emitted from the LD _A-1 of the LD module 2A is received by the PD ₁₃ to PD ₂₀ of the PD module 7. Moreover, the reflected light of the light emitted from LDA _-2 is received by PD _{21 to} PD ₂₆ . Moreover, the reflected light of the light emitted from LDA _-3 is received by PD _{27 to} PD ₃₀ . Further, the reflected light of the light emitted from LDA _-4 is received by PD ₃₁ and PD ₃₂ .

Each LD module _{2A, 2B LD A-1 ~LD} A-4, LD B-1 ~LD B-4 of emits light at a predetermined order. Further, the _LD A-1 _{to Ld} of the _A-4 and LD module _{2B LD B-1 ~LD B-} 4 of the LD module 2A, alternately emit light. The emission of one LD of the _{LD A-1 ~LD A-4} , the charge of the capacitor _{C A} is _discharged, the emission of one LD of the _{LD B-1 ~LD B-4} , the capacitor _{C B} The electric charge is discharged.

Each LD module 2A, in 2B, the capacitor _C A, after either _{LD A-1 ~LD A-4} , LD B-1 ~LD B-4 is emitted by the power of _{C B,} the capacitor _C A, _{C B} Is charged. That is, in each of the LD modules 2A and 2B, charging of the capacitors C _A and C _B and light emission of any of the LD _{A-1 to} LD _A-4 and LD _{B-1 to} LD _B-4 are repeatedly performed.

  The control unit 1 controls the LD modules 2A and 2B to switch the LD to emit light. Further, the control unit 1 controls the PD module 7 to switch the PD to receive light.

In the LD module 2B, during charging of the capacitor _{C B is} the light receiving operation of the _{LD B-1} ~LD _B-4 of the light emitting operation and _PD 1 _{-PD 12} can not. Further, in the LD module 2A, during charging of the capacitor _{C A is} receiving operation of the _{LD A-1} ~LD _A-4 of the light emitting operation and _PD 13 _{-PD 32} can not.

Light emitting operation of one of _{LD B-1 ~LD B-4} in the LD module 2B is in a non-emission period of _{LD A-1 ~LD A-4} in the LD module 2A, and a capacitor _{C A} in the LD module 2A Performed within the charging period. In addition, the light emitting operation of any of LD _{A-1 to} LD _{A- 4} in the LD module 2A is within the non-light emitting period of LD _{B-1 to} LD _{B-4 in} the LD module 2B and the capacitor C in the LD module 2B. _It is performed within the charging period of _B.

In the light emission period of each of the LD modules 2A and 2B, LD _{A-1 to} LD _{A- 4} and LD _{B-1 to} LD _B-4 , the corresponding PD ₁ to PD ₃₂ perform a light receiving operation.

In each of the LD modules 2A and 2B, the charging periods of the capacitors C _A and C _B are longer than the light emission periods of the LD _{A-1 to} LD _A-4 and LD _{B-1 to} LD _B-4 . Each LD module 2A, in 2B, the capacitor _C A, after completion of charging _{C B,} light emission of any of the _{LD A-1 ~LD A-4} , LD B-1 ~LD B-4 is started immediately The

Further, during the charging period of the capacitor _{C B} in LD module 2B, the charging of the capacitor _{C A} in the LD module 2A is started. Further, during the charging period of the capacitor _{C A} in the LD module 2A, charging of the capacitor _{C B} in LD module 2B it is started.

According to the embodiment described above, the LD modules 2A and 2B are configured from the plurality of LDs, the switching element Q, and the common (single) capacitors C _A and C _B. For this reason, by supplying electric power from the capacitors C _A and C _B common to the LD selected by the switching element Q and causing the LD to emit light sequentially, the capacitors C _A and C _B and peripheral components (for example, electric wires, etc.) ), The electrical circuit can be simplified. In addition, a plurality of LD modules 2A and 2B are provided so that one of the LD modules emits light during the non-light emission period of the other LD module. For this reason, for example, since the capacitor is charged in the other LD module, even if the LD cannot emit light, one LD module can emit light by the power of the capacitor in one LD module. . That is, when the light emitting operation is performed in one LD module, the other LD module can perform the charging operation, and thus the object detection apparatus 100 can shorten the light emitting cycle. Also, by reducing the number of LD modules installed, an increase in the number of parts can be suppressed and the electric circuit can be prevented from becoming complicated.

In the above embodiment, in each of the LD modules 2A and 2B, any one LD can emit light by the electric power stored in the capacitors C _A and C _B by one charge. For this reason, in each LD module 2A, 2B, by repeating the charging of the capacitors C _A and C _B and the selection and light emission of the LD by the switching element Q, each LD can be caused to emit light sequentially.

  In the above embodiment, the light emission operation of one of the LDs in one LD module is performed within the capacitor charging period in the other LD module. For this reason, when one of the LD modules is charging a capacitor, the other LD module emits one of the LDs, thereby enabling the object detection device 100 to further shorten the light emission cycle. Become.

  In each of the above embodiments, in each LD module, the capacitor charging period is longer than the LD light emitting period, and the light emitting operation of any LD is started immediately after the capacitor charging is completed. For this reason, the light emission cycle can be further shortened as the object detection apparatus 100.

  Furthermore, in the above embodiment, charging of the capacitor in the other LD module is started during the charging period of the capacitor in one LD module. For this reason, since the charging time of the capacitors in the plurality of LD modules partially overlap, it is possible to shorten the charging cycle as the object detection device 100 and further shorten the light emission cycle accordingly.

  The present invention can employ various embodiments other than those described above. For example, in the above embodiment, an example in which two LD modules having four LDs are provided has been described, but the present invention is not limited to this. The number of LD modules installed may be three or more. In addition, the number of LDs in each LD module may be two, three, or five or more.

  Moreover, although the example which provided 32 PD in PD module was shown in the above embodiment, this invention is not limited only to this. The number of PDs in the PD module may be 31 or less, or 33 or more. Further, the number of PDs that perform light receiving operation corresponding to the light emitting operation of each LD may be one or plural.

Further, in the above embodiment, in each LD module, an example in which one LD can emit light by the power stored in the power storage unit (capacitors C _A and C _B ) by one charge is shown. The invention is not limited to this. In addition to this, for example, two or more LDs may be capable of emitting light by electric power stored in the power storage unit by one charge. That is, the power storage capacity of the power storage unit may be a capacity that allows one LD to emit light, or may be a capacity that allows two or more LDs to emit light.

  Moreover, although the electrical storage part was comprised by the capacitor and the light emission selection part was comprised by MOS-FET in the above embodiment, this invention is not limited only to these. In addition to this, for example, the power storage unit may be configured by a rechargeable storage battery. Further, the light emission selection unit may be constituted by a transistor, a switch, a relay, or the like.

  Furthermore, although the example which applied this invention to the vehicle-mounted object detection apparatus 100 was given in the above embodiment, this invention is applicable also to the object detection apparatus of another use.

1 control unit 2A, 2B laser diode module 100 object detector C _{A, C B} capacitor (power storage unit)
LD, LD _{A-1 to} LD _{A- 4} , LD _{B-1 to} LD _B-4 Laser diode PD, PD _{1 to} PD ₃₂ photodiode (light receiving element)
Q, Q _{A-1 to} Q _A-4 , Q _{B-1 to} Q _B-4 switching elements (light emission selection unit)

Claims (5)

A plurality of laser diodes;
A power storage unit that is a power source of the laser diode;
Among the plurality of laser diodes, a light emission selection unit for selecting a laser diode to emit light,
A light receiving element that receives light reflected by an object of light projected from the laser diode;
An object comprising: a controller that repeats charging of the power storage unit and light emission of the laser diode selected by the light emission selection unit, and detects the object based on a light reception signal output from the light receiving element In the detection device,
A plurality of laser diode modules each including the plurality of laser diodes, the light emission selection unit, and the power storage unit common to the plurality of laser diodes;
The object detection device characterized in that the light emitting operation of one of the laser diode modules among the plurality of laser diode modules is performed within a non-light emitting period of the laser diode in the other laser diode module. . The object detection apparatus according to claim 1,
In each of the laser diode modules, one laser diode can emit light by the electric power stored in the power storage unit by one charge. In the object detection device according to claim 1 or 2,
The light emitting operation of any one of the laser diodes in the one laser diode module is performed within a charging period of the power storage unit in the other laser diode module. In the object detection device according to any one of claims 1 to 3,
In each of the laser diode modules,
The charging period of the power storage unit is longer than the light emission period of each laser diode,
An object detection device characterized in that the light emitting operation of any one of the laser diodes is started immediately after charging of the power storage unit is completed. In the object detection device according to any one of claims 1 to 4,
The object detection apparatus, wherein charging of the power storage unit in the other laser diode module is started during a charging period of the power storage unit in the one laser diode module.

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