JP2019090679A - Object detection apparatus - Google Patents

Abstract

To improve both the accuracy in detecting an object and the accuracy in diagnosing a failure in a light emitting device.SOLUTION: An object detection apparatus 100 causes a plurality of LDs (laser diodes) provided in an LD module 2 to emit light to project laser beams, scans a predetermined range with the laser beams with a scanning unit 4, deflects light reflected on an object within the predetermined range with the scanning unit 4 and causes an APD array 7a to receive the deflected light, and detects the presence/absence of the object and the distance to the object on the basis of a light receiving signal output from the APD array 7a. The object detection apparatus comprises: a condensation guide 15 that condenses, among the laser beams projected from the LDs, partial light not incident on the scanning unit 4 and emits the light in a direction other than the scanning unit 4 side; and an optical sensor 18 that receives light emitted from the condensation guide 15 and outputs a light receiving signal according to a light receiving state. The object detection apparatus integrates the light receiving signals from the optical sensor 18 over a predetermined period, and diagnoses the presence/absence of a failure in the LD module 2 on the basis of output from an integrating circuit.SELECTED DRAWING: Figure 1B

Description

  The present invention relates to an object detection apparatus that projects light from a light emitting element, receives the reflected light by a light receiving element, and detects an object based on a light receiving signal output from the light receiving element, and in particular, the light emitting element The present invention relates to a technology for diagnosing the presence or absence of a failure.

  An object detection device such as a laser radar is mounted on a vehicle or the like having a collision prevention function. For example, as disclosed in Patent Documents 1 to 8, the object detection apparatus projects light from the light emitting element, receives the reflected light by the light receiving element, and is based on the light receiving signal output from the light receiving element. To detect the presence or absence of an object and the distance to the object.

  A laser diode or the like is used as the light emitting element. As the light receiving element, a photodiode, an avalanche photodiode or the like is used. In addition, a plurality of light emitting elements and light receiving elements may be used in order to secure the light emitting / receiving range and the light emitting / receiving amount.

  The object detection apparatus of Patent Documents 1 to 8 includes a scanning unit that scans light in the horizontal direction and the vertical direction in order to emit and receive light in a wide range and to miniaturize the apparatus. The scanning unit reflects light projected from the light emitting element by the mirror and scans the light in a predetermined range by rotating or swinging the mirror. In addition, the scanning unit may reflect light reflected by an object within a predetermined range by the mirror and guide the light to the light receiving element by rotating or swinging the mirror.

  If an optical system such as a light emitting element or a light receiving element is broken, the presence or absence of an object or the distance to the object can not be accurately detected. Therefore, the object detection devices of Patent Document 1 and Patent Documents 4 to 7 guide a part of the light projected from the light emitting element to the light receiving element by the light guide portion inside, and the light receiving signal output from the light receiving element Based on the self-diagnosis of the failure of the optical system. Specifically, for example, from the result of comparing the signal level of the light reception signal with the threshold value, the presence or absence of a failure of the optical system is diagnosed. The light guiding portion is configured of a through hole formed in a wall, a mirror or the like, an optical fiber, a light guiding member, a reflecting member, a light transmitting window plate on the front of the device, or the like. Patent Document 4 separately provides a light emitting element and a light receiving element for failure diagnosis separately from a light emitting element and a light receiving element for object detection, and diagnoses a failure of the light emitting element and the light receiving element for object detection separately. It is also disclosed.

  Although the object detection devices of Patent Document 2 and Patent Document 3 also guide part of the light projected from the light emitting element to the light receiving element by the light guide inside, based on the light receiving signal output from the light receiving element Calculate the correction value. Then, when the distance to the object is detected, the detected value is corrected by the correction value.

  The object detection device of Patent Document 8 detects high intensity of background light in a predetermined range that causes a decrease in distance measurement accuracy, based on a monitor voltage of a light receiving element for object detection. In addition, another light receiving element receives light projected from the light emitting element and traveling toward the anti-scanning portion side, and the light emission timing of the light emitting element is detected based on the light receiving signal output from the light receiving element.

JP 2002-31685 A JP, 2010-204015, A JP, 2012-93256, A Unexamined-Japanese-Patent No. 10-31064 Patent No. 4160610 Patent No. 5472752 gazette Japanese Patent Application Laid-Open No. 2002-286844 JP-A-9-318736

  In order to diagnose these failures using a light emitting element and a light receiving element for object detection, it is necessary to provide a light guide inside the object detecting device. However, when light projected toward the target enters the light guide during detection of the target, this light becomes stray light and is guided to the light receiving element for target detection, and the presence or absence of the target and the target The detection accuracy of the distance may decrease. In order to suppress this stray light, it is effective to reduce the light transmittance of the light guide, but if doing so, the level of the light reception signal output from the light receiving element becomes low at the time of fault diagnosis, and the fault diagnostic accuracy Will decrease.

  If a light receiving element for failure diagnosis is provided separately from the light receiving element for object detection, the failure of the light emitting element for object detection can be diagnosed, but the number of parts increases, so the cost of the apparatus is increased. It leads to the up. Therefore, it is conceivable to use a light receiving element that is cheaper than the light receiving element for detecting an object as a light receiving element for failure diagnosis, but then the performance of the light receiving element is inferior to the performance of the light receiving element for detecting an object. , There is a risk that the diagnostic accuracy of the failure will be low.

  An object of the present invention is to provide an object detection apparatus capable of improving both detection accuracy of an object and diagnosis accuracy of a failure of a light emitting element or the like.

  The object detection apparatus according to the present invention receives a light emitting element for projecting light, a scanning unit for scanning the projection light projected from the light emitting element in a predetermined range, and light reflected by the object within the predetermined area of the projection light A first light receiving element that outputs a first light receiving signal according to the light receiving state, an object detection unit that detects an object based on the first light receiving signal, and a part of the projection light that is projected from the light emitting element It is provided in the predetermined direction side of the condensing part which condenses the partial light which does not enter into the scanning part and is emitted in the predetermined direction other than the scanning part side and is emitted from the condensing part A second light receiving element that receives light and outputs a second light reception signal according to the light reception state, an integration circuit that integrates the second light reception signal over a predetermined first period, and a failure based on the output of the integration circuit And a fault diagnosis unit that diagnoses the presence or absence of

  According to the above, since the second light receiving element for failure diagnosis is provided separately from the first light receiving element for object detection, the light emitting element (or the drive circuit thereof regardless of the presence or absence of a failure of the first light receiving element) Etc.) can be diagnosed. In addition, among the projection light projected from the light emitting element, partial light which does not enter the scanning part is collected by the condensing part and emitted to the second light receiving element provided in a predetermined direction other than the scanning part. The light projected from the light emitting element to the object via the scanning unit is not incident on the light collecting unit, and the stray light is not generated in the light collecting unit and the stray light is not guided to the first light receiving element. Therefore, based on the first light receiving signal output from the first light receiving element, the object detection unit can accurately detect the target. Furthermore, partial light of projected light not incident on the scanning unit is collected by the light collecting unit and then received by the second light receiving element, and the second light receiving signal output from the second light receiving element is integrated by the integration circuit. Integration is performed over a predetermined first period. For this reason, even if the intensity of the partial light is weak or the performance of the second light receiving element is lower than the performance of the first light receiving element, the voltage of the second light receiving signal based on the partial light is Since time integration is performed and the level of the second light reception signal increases, the presence or absence of a failure of a light emitting element or the like can be accurately diagnosed by the failure diagnosis unit based on the output of the integration circuit. Therefore, it is possible to improve both the detection accuracy of the object and the diagnosis accuracy of the failure of the light emitting element or the like.

  In the present invention, the light emitting module may further include a light emitting module in which a plurality of light emitting elements are arranged, and a light emission control unit for controlling the light emitting operation of the plurality of light emitting elements such that the light emitting surface of the light emitting element faces the scanning unit side. In this case, the condensing unit condenses part of the projected light projected from each light emitting element.

  In the present invention, the light emission control unit causes the light emitting element to emit light a plurality of times at predetermined time intervals during a diagnosis period other than the target object detection period in which the scanning unit scans the projection light into a predetermined range, and the integration circuit The second light reception signal sequentially output from the element may be integrated.

  In the present invention, the light emission control unit causes the plurality of light emitting elements to emit light sequentially at a predetermined time interval during the diagnosis period, and the first period during which the integration circuit integrates the second light reception signal is longer than the time interval. The time interval may be shorter than the multiplication time obtained by multiplying the number of light emitting elements.

  Alternatively, in the present invention, after the light emission control unit causes the same light emitting element to emit light a predetermined number of times at a predetermined time interval during the diagnosis period, switching of the light emitting elements to be emitted is repeated sequentially, and the integration circuit generates the second light reception signal. The first period during which the second light source is integrated may be longer than the time interval and shorter than a multiplication time obtained by multiplying the time interval by the number of light emissions of the same light emitting element.

  Further, in the present invention, a discharge unit for discharging the integration circuit may further be provided. In this case, after the integration circuit integrates the second light reception signal for the first period, the light emitting element stops emitting light for a predetermined second period, and the discharge unit discharges the integration circuit.

  In the present invention, the failure diagnosis unit may determine the presence or absence of a failure based on the result of comparing the output voltage of the integration circuit with a predetermined threshold.

  In this case, the failure diagnosis unit may determine that there is no failure if the output voltage of the integration circuit is equal to or higher than the threshold, and may determine that there is a failure if the output voltage is less than the threshold.

  Alternatively, the threshold value includes a first threshold value and a second threshold value higher than the first threshold value, and the failure diagnosis unit compares the first threshold value and the second threshold value with the output voltage of the integration circuit, and the output voltage is If the output voltage is lower than the first threshold or higher than the second threshold, it may be determined that there is a failure.

  Furthermore, in the present invention, the response speed of the second light receiving element may be slower than the response speed of the first light receiving element.

  According to the present invention, it is possible to provide an object detection apparatus capable of improving both the detection accuracy of an object and the diagnosis accuracy of a failure of a light emitting element or the like.

It is the figure which showed the state which looked at the optical system of the target object detection apparatus by embodiment of this invention from upper direction. It is the figure which showed the state from which the angle of the mirror of FIG. 1A changed. It is the figure which showed the state which looked at the optical system of the target object detection apparatus of FIG. 1A from back. It is a side view of the LD module of FIG. 1A, a condensing guide, and an optical sensor. It is the figure which showed the electric constitution of the target object detection apparatus of FIG. 1A. It is the figure which showed the detail of the integration circuit of FIG. It is the figure which showed the operation | movement timing of the target object detection apparatus of FIG. 1A. It is the flowchart which showed the failure diagnostic operation | movement of the target object detection apparatus of FIG. 1A. It is the timing chart which showed an example of the light emission / reception state in the diagnosis period of the object detection apparatus of FIG. 1A, and an integration state. It is the timing chart which showed the other example of the light emission / reception state in the diagnosis period of the target object detection apparatus of FIG. 1A, and an integration state. It is the flowchart which showed the other example of the failure diagnostic operation | movement of the target object detection apparatus of FIG. 1A.

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

  First, the structure and operation of the optical system of the object detection apparatus 100 according to the present embodiment will be described with reference to FIGS. 1A to 3.

  FIGS. 1A and 1B are diagrams showing the optical system of the object detection apparatus 100 as viewed from above. In FIG. 1A and FIG. 1B, the angle of the mirror 4a is different. FIG. 2 is a view showing the optical system of the object detection apparatus 100 as viewed from the rear (in FIG. 1A, from the lower side, that is, the opposite side to the object 50). In FIG. 1A and FIG. 2, the angle of the mirror 4a is the same. FIG. 3 is a view showing the LD module 2, the condensing guide 15, and the optical sensor 18 as viewed from the side (left side in FIG. 1A).

  The object detection device 100 comprises, for example, a laser radar mounted on a motor vehicle. The optical system of the object detection apparatus 100 includes an LD (Laser Diode) module 2, a light projecting lens 14, a scanning unit 4, a transmission window 20, a light receiving lens 16, a reflecting mirror 17, an APD (Avalanche Photo Diode) array 7a, It comprises a guide 15 and a light sensor 18.

  Among them, the LD module 2, the light projection lens 14, the scanning unit 4, and the transmission window 20 are light projection optical systems. The transmission window 20, the scanning unit 4, the light receiving lens 16, the reflecting mirror 17, and the APD array 7a are light receiving optical systems. The condensing guide 15 and the light sensor 18 are components for failure diagnosis of the LD module 2.

  These optical systems are accommodated in the case 21 of the object detection apparatus 100. The front surface (object 50 side) of the case 21 is open. A transmission window 20 is provided on the front of the case 21. The transmission window 20 is formed of a rectangular window frame and a translucent plate member fitted in the window frame (not shown).

  The object detection device 100 is installed at the front, rear or left and right sides of the vehicle such that the transmission window 20 is directed to the front, rear or left and right of the vehicle. The object 50 is a preceding vehicle, a person, or another object outside the object detection device 100.

As shown in FIG. 3, the LD module 2 includes a plurality of LD ₁ to LD ₄ . In FIG. 3, the light emitting surfaces of the LD _{1 to} LD ₄ are directed to the front side. The dashed arrows represent partial light (leakage light) described later. The LD _{1 to} LD ₄ are light emitting elements for projecting high-power laser light (light pulse). A plurality of LD _{1 to} LD ₄ are arranged in the vertical direction (the same direction as the vertical direction in FIG. 2) such that the light emitting surface faces the scanning unit 4 side. Hereinafter, LD ₁ to LD ₄ are collectively referred to as LD. The LD module 2 is an example of the “light emitting module” in the present invention.

  The APD array 7a shown in FIG. 1A and the like includes a plurality of APDs (not shown). The plurality of APDs are arranged in an array in the vertical direction or the horizontal direction in FIG. Each APD is disposed so that the light receiving surface faces the reflecting mirror 17 side. Each APD is a light receiving element that receives the reflected light of the laser light (projected light) projected from the LD module 2 by the object 50. That is, the APD array 7a is a light receiving element for detecting an object, and is an example of the "first light receiving element" in the present invention.

  The scanning unit 4 is also called an optical deflector. The scanning unit 4 includes a mirror 4a and a motor 4c. The mirror 4a is formed in a rectangular plate shape. The front and back surfaces of the mirror 4a are reflection surfaces.

  As shown in FIG. 2, a motor 4c is provided below the mirror 4a. The rotation axis 4j of the motor 4c is parallel to the vertical direction. A connecting shaft (not shown) at the center of the mirror 4a is fixed to the upper end of the rotation shaft 4j of the motor 4c. The mirror 4a rotates in conjunction with the rotation shaft 4j of the motor 4c.

  In the case 21, the LD module 2, the light projection lens 14, the condensing guide 15, and the light sensor 18 are disposed around the upper portion of the mirror 4 a of the scanning unit 4. The light receiving lens 16, the reflecting mirror 17, and the APD array 7a are disposed around the lower part of the mirror 4a. A light shielding plate 22 is provided below the LD module 2, the light projecting lens 14, the light collecting guide 15 and the light sensor 18 and above the light receiving lens 16, the reflecting mirror 17 and the APD array 7 a. The light shielding plate 22 is fixed in the case 21 and divides the light transmitting path and the light receiving path. A through hole 22 h is formed in the light shielding plate 22 so as not to interfere with the mirror 4 a of the scanning unit 4. The transmission window 20 is provided between the scanning unit 4 and the scanning range of the laser light, and divides the inside of the object detection device 100 from the outside.

  The light emitting and receiving path at the time of detecting the object 50 is as shown by arrows of dashed dotted line and dashed dotted line in FIGS. 1A and 2. Specifically, as shown by arrows of dashed-dotted lines in FIG. 1A and FIG. 2, the laser light projected from the LD of the LD module 2 is adjusted in spread by the light projection lens 14, and It hits the upper half area of the front or back of the mirror 4a. At this time, the motor 4c is rotated to change the angle (direction) of the mirror 4a, and the front or back surface of the mirror 4a is at a predetermined angle facing the object 50 (for example, the mirror 4a shown by a solid line in FIG. State). Thereby, after the laser beam from the LD module 2 is transmitted through the light projection lens 14, it is reflected by the upper half area of the front or back surface of the mirror 4 a and transmitted through the transmission window 20 to a predetermined range outside the case 21. It is scanned. That is, the scanning unit 4 deflects the laser light from the LD module 2 into a predetermined range.

  The scanning angle range Z shown in FIG. 1A is a predetermined range (top view) in which the laser light from the LD module 2 is reflected by the front or back surface of the mirror 4 a of the scanning unit 4 and projected from the object detection device 100 . That is, the scanning angle range Z is a detection range of the object 50 by the object detection device 100.

  As described above, the laser light projected from the object detection device 100 into the predetermined range is reflected by the object 50 in the predetermined range. The reflected light passes through the transmission window 20 and strikes the area of the lower half of the front or back of the mirror 4a, as shown by the double-dotted arrow in FIGS. 1A and 2. At this time, the motor 4c is rotated to change the angle (direction) of the mirror 4a, and the front or back surface of the mirror 4a is at a predetermined angle facing the object 50 (for example, the mirror 4a shown by a solid line in FIG. State). Thereby, the reflected light from the object 50 is reflected by the area of the lower half of the surface or the back surface of the mirror 4 a and is incident on the light receiving lens 16. That is, the scanning unit 4 deflects the reflected light from the object 50 to the light receiving lens 16 side. Then, the reflected light is condensed by the light receiving lens 16 and then reflected by the reflecting mirror 17 to be received by the APD of the APD array 7a. That is, the scanning unit 4 guides the reflected light from the object 50 to the APD array 7 a via the light receiving lens 16 and the reflecting mirror 17.

  The light collecting guide 15 is formed in a cup shape as shown in FIG. 3 by a material having a light guiding property. The area of the light incident surface 15a of the light collecting guide 15 is larger than the area of the light exit surface 15b. The condensing guide 15 is disposed on the side of the LD module 2 so that the light incident surface 15 a is perpendicular to the light emitting surface of each LD of the LD module 2. Further, as shown in FIG. 1A and the like, the condensing guide 15 is disposed on the side of the transmission window 20 with respect to the LD module 2.

  As shown in FIG. 1A, the diameter in the left-right direction of the light incident surface 15 a of the light collecting guide 15 is larger than the width in the left-right direction of the LD module 2. In addition, the left end portion of the incident surface 15a is a scanning portion 4 from a front surface of the LD module 2 (a surface facing the left side in FIG. 1 and a surface where the light emitting surface of each LD is exposed as shown in FIG. Located on the side. As shown in FIG. 3, the diameter in the vertical direction of the light incident surface 15 a is larger than the width in the vertical direction of the LD module 2. As a result, among the laser beams projected from the respective LDs of the LD module 2, the light traveling toward the transmission window 20 enters the light incident surface 15 a of the condensing guide 15.

As another example, the diameter in the left-right direction of the light incident surface 15 a may be equal to the width in the left-right direction of the LD module 2 or smaller than the width in the left-right direction of the LD module 2. The diameter of the light incident surface 15 a in the vertical direction may be equal to the width of the LD module 2 in the vertical direction or smaller than the width of the LD module 2 in the vertical direction. When the diameter of the light incident surface 15a in the vertical direction is smaller than the width of the LD module 2 in the vertical direction, the diameter of the light incident surface 15a in the vertical direction is set to the light emitting surface of the LD _{1 at} the top of the LD module 2. And the light emitting surface of the LD ₄ located at the lowermost position.

  The condensing guide 15 is a part of the laser light projected from the LD module 2 and introduces from the light incident surface 15a a part of light (leakage light) that does not enter the mirror 4a after the projection and collects the light internally. Then, the light is emitted from the light exit surface 15b to the transmission window 20 side. The condensing guide 15 is an example of the “condensing part” in the present invention.

  The light sensor 18 comprises a phototransistor. The response speed of the phototransistor (such as the speed for outputting a current value corresponding to the intensity of the received light) is lower than that of the APD. The phototransistor is a light receiving element cheaper than the APD array 7a.

  The light sensor 18 is disposed on the transmission window 20 side of the condensing guide 15 so that the light receiving surface 18a (FIG. 3) faces the light emitting surface 15b of the condensing guide 15 (FIG. 1A). Although the light receiving surface 18a of the light sensor 18 and the light emitting surface 15b of the light collecting guide 15 are in contact with each other in FIG. 3 and the like, these surfaces 18a and 15b may be separated. The light sensor 18 receives the light emitted from the light exit surface 15 b of the light collecting guide 15. The optical sensor 18 is a light receiving element for failure diagnosis of the LD module 2 and is an example of the “second light receiving element” in the present invention.

  As shown in FIG. 1A, the condensing guide 15 and the light sensor 18 are disposed at positions where the laser light projected from the LD module 2 is not reflected by the mirror 4a and projected to a predetermined range. ing. Further, the condensing guide 15 and the light sensor 18 are disposed such that external light (such as sunlight) transmitted from the outside through the transmission window 20 does not enter.

  The light emitting and receiving path when diagnosing a failure of the LD module 2 is as shown by a broken arrow in FIG. 1B. Specifically, among the laser light projected from each LD of the LD module 2, a part of the laser light that leaks to the transmission window 20 without entering the mirror 4 a of the scanning unit 4 is the condensing lens 15. The light is introduced into the interior from the light entrance surface 15a. Then, the partial light is condensed inside the condenser lens 15, and then emitted from the light exit surface 15 b to the transmission window 20 side and received by the light sensor 18.

  Next, the electrical configuration of the object detection apparatus 100 will be described with reference to FIGS. 4 and 5.

  FIG. 4 is an electrical block diagram of the object detection apparatus 100. As shown in FIG. The object detection device 100 includes a control unit 1, an LD module 2, an LD drive circuit 3, a motor 4c, a motor drive circuit 5, an encoder 6, a light receiving module 7, comparators 8a and 8b, an ADC (Analog to Digital Converter) 9a, 9 b, DACs (Digital to Analog Converters) 13 a and 13 b, an optical sensor 18, an integration circuit 19, a storage unit 11, and an interface 12.

  The control unit 1 includes a microcomputer and the like, and controls the operation of each unit of the object detection device 100. The control unit 1 is provided with an object detection unit 1a, a failure diagnosis unit 1b, and a light emission control unit 1c.

  The storage unit 11 is composed of volatile or non-volatile memory. The storage unit 11 stores information for the control unit 1 to control each unit of the object detection apparatus 100, information for detecting the object 50, information for diagnosing a failure, and the like.

  The interface 12 comprises a communication circuit for communicating with an ECU (Electronic Control Unit) mounted on a vehicle. The control unit 1 transmits information such as a detection result of the object 50 and a diagnosis result of a failure to the ECU through the interface 12 and receives various control information.

  The LD module 2 is provided with the plurality of LDs described above, a capacitor 2 c for causing each LD to emit light, and the like. In FIG. 4, for convenience, one block of each of the LD and the capacitor 2c is shown.

  The light emission control unit 1 c of the control unit 1 controls the operation of each LD of the LD module 2 by the LD drive circuit 3. Specifically, the light emission control unit 1c causes the LD drive circuit 3 to emit light from the LD to project laser light. In addition, the light emission control unit 1 c sequentially switches the light emitting diodes. Furthermore, the light emission control unit 1 c causes the LD drive circuit 3 to stop the light emission of the LD to charge the capacitor 2 c.

  The motor 4 c is a drive source that rotates the mirror 4 a of the scanning unit 4. The control unit 1 controls the drive of the motor 4c by the motor drive circuit 5 to rotate the mirror 4a. Then, as described above, the control unit 1 scans the laser light projected from the LD in a predetermined range by rotating the mirror 4a, and the reflected light reflected by the object 50 in the predetermined range is the APD array 7a. Lead to In these cases, the control unit 1 detects the rotation state (rotation angle, rotation number, etc.) of the motor 4 c and the mirror 4 a based on the output of the encoder 6.

  The light receiving module 7 includes an APD array 7a, a TIA (Trans Impedance Amplifier) 7b, and a MUX (Multiplexer) 7c. As described above, in the APD array 7a, a plurality of APDs are arranged in an array. A plurality of TIA's 7b are provided corresponding to each APD. In FIG. 4, only one block of TIA 7b is shown for convenience.

  The APD of the APD array 7a outputs a current signal by receiving light. The TIA 7 b converts the current signal from the APD into a voltage signal and outputs the voltage signal to the MUX 7 c. The MUX 7 c selects one of the output signals (voltage signals) of the plurality of TIA 7 b and outputs the selected output signal to one of the comparators 8 a and 8 b. Thus, light reception signals corresponding to the light reception states of the respective APDs are sequentially output from the light reception module 7 to the comparators 8a and 8b.

  The comparators 8a and 8b, the ADCs 9a and 9b, and the DACs 13a and 13b are provided in pairs of two each. This is for speeding up by processing the light reception signal output from the light reception module 7 in two systems.

  The comparators 8a and 8b compare the output signal of the MUX 7c with a predetermined threshold to distinguish whether the output signal is a reflected light signal based on the reflected light by the object 50 or a noise. Specifically, for example, when the output signal of the MUX 7c is larger than the threshold, the comparators 8a and 8b indicate that the output signal is a reflected light signal, so that the ADC 9a corresponding to a predetermined signal (for example, high level signal) Output to 9b. The comparators 8a and 8b do not output predetermined signals to the ADCs 9a and 9b because they indicate that the output signal is noise if the output signal of the MUX 7c is less than or equal to the threshold.

  The control unit 1 sets the threshold with which the comparators 8a and 8b compare with the output signal of the MUX 7c via the DACs 13a and 13b. Specifically, the digital signal indicating the threshold value output from the control unit 1 is converted into an analog signal by the DACs 13a and 13b, and is input to the comparators 8a and 8b. The comparators 8a and 8b set thresholds based on the analog signals input from the DACs 13a and 13b.

  The ADCs 9 a and 9 b convert the analog signals (predetermined signals) output from the corresponding comparators 8 a and 8 b into digital signals at high speed, and output the digital signals to the control unit 1. Specifically, when a predetermined signal is output from the comparators 8 a and 8 b, the ADCs 9 a and 9 b convert the predetermined signal into a digital “1” signal and output it to the control unit 1. Further, when the predetermined signals are not output from the comparators 8a and 8b, the ADCs 9a and 9b output a digital "0" signal to the control unit 1.

  As described above, the light reception signal (voltage signal) corresponding to the light reception state of each APD is output from the light reception module 7 to the control unit 1 through the comparators 8a and 8b and the ADCs 9a and 9b. The operation of each part of the light receiving module 7, the comparators 8a and 8b, the ADCs 9a and 9b, and the DACs 13a and 13b is controlled by the control unit 1.

  The object detection unit 1a of the control unit 1 processes output signals from the ADCs 9a and 9b to extract feature points (such as maximum values) of the light reception signal from the light reception module 7 in a predetermined time. Then, the presence or absence of the object 50 and the distance to the object 50 are detected based on the feature points.

  Specifically, for example, the object detection unit 1a compares the light reception signal output from the light reception module 7 via the ADCs 9a and 9b with a predetermined threshold. Then, if the light reception signal is equal to or higher than the threshold, it is determined that the object 50 is present, and if the light reception signal is less than the threshold, it is determined that the object 50 is not present. Further, for example, the object detection unit 1a detects the maximum value of the light reception signal which is equal to or higher than the threshold, and detects the light reception time of the reflected light by the object 50 based on the maximum value. Then, the distance to the object 50 is calculated based on the reception time of the reflected light and the projection time of the laser light from each LD (a so-called TOF (Time of Flight) method).

  The light sensor 18 includes the above-described phototransistor, and outputs a light reception signal (voltage signal) by receiving light. The integration circuit 19 integrates the light reception signal from the light sensor 18.

  FIG. 5 is a diagram showing the details of the integration circuit 19. The integrating circuit 19 includes an operational amplifier 19a, a capacitor C, input / output terminals P1 and P2, and resistors R1 and R2. One end of a resistor R1 is connected to the inverting input terminal (-) of the operational amplifier 19a, and the other end of the resistor R1 is connected to an input terminal P1. The noninverting input terminal (+) of the operational amplifier 19a is grounded. A capacitor C is connected in parallel to the operational amplifier 19a. One end of the discharge resistor R2 and the output terminal P2 are connected to the output terminal of the operational amplifier 19a, and the other end of the discharge resistor R2 is grounded. The resistance value of the discharge resistor R2 is larger than the resistance value of the resistor R1.

  The light reception signal (voltage signal) output from the light sensor 18 is input to the integration circuit 19 from the input terminal P1. Then, the light reception signal is integrated (accumulated) over time by the operational amplifier 19a and the capacitor C, and the resultant output voltage is output from the output terminal P2. When the light reception signal is not input from the light sensor 18 to the integration circuit 19, the charge accumulated in the capacitor C is discharged to the ground via the discharge resistor R2. The discharge resistor R2 is an example of the "discharge portion" in the present invention.

  The failure diagnosis unit 1 b of the control unit 1 diagnoses the presence or absence of a failure in the LD module 2, the LD drive circuit 3, or the light emission control unit 1 c based on the output of the integration circuit 19. Specifically, the failure diagnosis unit 1 b compares the output voltage of the integration circuit 19 with a predetermined threshold, and determines the presence or absence of a failure of the LD module 2 or the like based on the comparison result. In the following, the failure of the LD of the LD module 2 is taken as an example.

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

  FIG. 6 is a diagram showing the operation timing of the object detection device 100. As shown in FIG. Specifically, FIG. 6 shows the operation of each unit while the mirror 4a of the scanning unit 4 makes one rotation from the origin.

  The origin (star mark) of the mirror 4a of the scanning unit 4 is, for example, as shown by a dotted line in FIG. 1A, both plate surfaces of the mirror 4a are perpendicular to the optical axis (dotted line) of laser light from the LD module 2. Position where the The mirror 4a keeps rotating in one direction (counterclockwise in FIG. 1A) at a predetermined rotation speed (constant speed).

By driving the motor 4c of the scanning unit 4, while the mirror 4a is rotated from the origin by a predetermined rotation angle theta _1, a laser beam is projected from the LD of the LD module 2, the laser beam by the mirror surface 4a This is a scanning period in which a predetermined range in front of the object detection device 100 is scanned. In the scanning period theta _1, the laser light projected to a predetermined range is reflected by the object 50, the reflected light is reflected by the mirror surface 4a, via the light-receiving lens 16 and reflecting mirror 17, APD The light is received by the APD of the array 7a. Then, the object detection unit 1a detects the presence / absence of the target 50 based on the light reception signal input from the light reception module 7 via the comparators 8a and 8b and the ADCs 9a and 9b according to the light reception state of the APD of the APD array 7a. The distance to the object 50 is detected. That is, the scanning period theta ₁ by the mirror surface 4a is the object detection period.

The scanning period theta ₁ by the mirror surface 4a is different from the scanning angle range Z shown in Figure 1A. As will be described later, also the scanning period theta ₅ by the rear surface of the mirror 4a, is different from the scanning angle range Z. The scanning angle range Z is the sum of the angle range on the object 50 side where the mirror 4a scans the laser beam by the surface and the angle range on the object 50 side where the mirror 4a scans the laser beam by the back side as described later. is there.

After passing the scanning period theta _1, while the mirror 4a is rotated by a predetermined rotation angle theta ₂ is a rest period. In idle period theta _2, the light emitting operation of the LD, the light receiving operation of each unit of the light receiving module 7, the comparators 8a, 8b and ADC9a, 9b of the signal processing operation, the detection operation of the object detecting unit 1a, and the failure diagnosis operation of the diagnosis unit 1b etc. Will be paused. The same applies to idle periods θ ₄ and θ ₆ described later.

After passing the rest period theta _2, while the mirror 4a is rotated by a predetermined rotation angle theta ₃ is a diagnostic period. In the diagnosis period theta _3, the laser light projected from the LD of the LD module 2 parts light, and focused by the focusing optical guide 15, and received by the optical sensor 18 (see FIG. 1B), the optical sensor 18 The output light reception signal is integrated by the integration circuit 19. Then, based on the output of the integration circuit 19, the failure diagnosis unit 1b diagnoses a failure of the LD module. Further, the diagnosis period theta _3, the laser light projected from the LD is also reflected by the surface and the back surface of the mirror 4a, not be scanned in a predetermined range.

After passing the diagnosis period theta _3, also a rest period during which the mirror 4a is rotated by a predetermined rotation angle theta _4. Then, after passing the rest period theta _4, while the mirror 4a is rotated by ₅ theta predetermined rotation angle, the laser beam is projected from the LD of the LD module 2, a predetermined range said laser beam is a rear surface of the mirror 4a It is a scanning period to be scanned. In the scanning period theta _5, when the laser light projected to a predetermined range is reflected by the object 50, the reflected light is reflected by the rear surface of the mirror 4a, via the light-receiving lens 16 and reflecting mirror 17, APD Light is received by the APD of the array. Then, the object detection unit 1a detects the presence / absence of the target 50 based on the light reception signal input from the light reception module 7 via the comparators 8a and 8b and the ADCs 9a and 9b according to the light reception state of the APD of the APD array 7a. The distance to the object 50 is detected. That is, the scanning period theta ₅ by the rear surface of the mirror 4a, like the scanning period theta _1, an object detection period.

After passing the scanning period theta _5, also a rest period during which the mirror 4a is rotated by a predetermined rotation angle theta _6. Then, past the rest period theta _6, back mirror 4a is the origin, the revolution state. Thereafter, the subsequent periods θ _{1 to} θ ₆ are repeated again.

FIG. 7 is a flowchart showing the failure diagnosis operation of the object detection apparatus 100. First, the control unit 1 detects the rotation angle of the mirror 4a of the scanning unit 4 based on the output of the encoder 6 (step S1 in FIG. 7). When the rotation angle of the mirror 4 a reaches an angle θ 3 _S (FIG. 6, θ 3 _S = θ ₁ + θ ₂ ) at which failure diagnosis is started (step S2 in FIG. 7: YES), the light emission control unit 1 c controls the LD of the LD module 2 The light emission process is performed (step S3 in FIG. 7). Further, the control unit 1 executes the light reception process by the light sensor 18 (step S4 in FIG. 7), and executes the integration process by the integration circuit 19 (step S5 in FIG. 7).

Each process of steps S3 to S5 of FIG. 7 is executed as shown in FIG. 8, for example. FIG. 8 is a timing chart showing an example of the light transmission / reception state and the integration state during the diagnosis period θ3 of the object detection apparatus 100. As shown in FIG. 8A, the light emission control unit 1c causes the LD ₁ , LD ₂ , LD ₃ and LD ₄ of the LD module 2 to sequentially emit light at a predetermined time interval T2 (step S3 in FIG. 7). Each time LD ₁ to Ld ₄ emits _light, some light of the projected laser beam from LD 1 to Ld ₄ is guided is condensed by the light guide 15 to the optical sensor 18. Therefore, as shown in FIG. 8B, the light sensor 18 sequentially receives part of the laser light projected from the LD ₁ to LD ₄ and receives a light reception signal (voltage signal) according to the light reception state. It outputs to the integrating circuit 19 (step S4 in FIG. 7). As shown in FIG. 8C, the integration circuit 19 integrates the voltage of the light reception signal sequentially input from the light sensor 18 over time for a predetermined period T1 (integration period), and outputs the integrated value to the control unit 1 (Step S5 of FIG. 7). The integration period T1 corresponds to the "first period" in the present invention.

As described above, by integrating the light reception signal from the light sensor 18 in the integration circuit 19 for a predetermined period T1, the level (voltage value) of the light reception signal is increased. The integration period T1 of the integration circuit 19 shown in FIG. 8 is longer than the time interval T2 for causing the LD _{1 to} LD ₄ to emit light, and the time interval T2 is multiplied by the number N of LD ₁ to LD ₄ (N = 4 in this example). It is set shorter than the multiplication time (T2 × N) (T2 <T1 <N · T2).

When the light emission control unit 1 c causes the LD _{1 to} LD ₄ to emit light once, the light emission control unit 1 c stops the light emission of the LD _{1 to} LD ₄ for a predetermined period T 3 (light emission stop period). During this period T3, the light sensor 18 does not receive light and does not output a light reception signal. Therefore, the light reception signal is not input to the integration circuit 19, and the charge accumulated in the capacitor C of the integration circuit 19 discharges the discharge resistor R2. Discharged to ground via From the integration start time in the period T1, the time until the discharge end of the period T3, the mirror 4a of the scanner 4, according to the rotation from the start angle theta _3S diagnosis period theta ₃ of Figure 6 to the end angle theta _3E It is set shorter than time. The light emission stop period T3 corresponds to the "second period" in the present invention.

Further, each process of steps S3 to S5 of FIG. 7 may be executed as shown in FIG. 9, for example. FIG. 9 is a timing chart showing another example of the light transmission / reception state and the integration state during the diagnosis period θ3 of the object detection apparatus 100. As shown in FIG. 9 (a), the light emission control portion 1c of the _LD 1 to Ld ₄ of the LD module 2, (4 times in this example) the same LD ₁ at a predetermined time interval T2 predetermined times intermittently To emit light (step S3 in FIG. 7). Each time the LD ₁ emits light, some light of the laser light projected from the LD ₁ is guided is condensed by the light guide 15 to the optical sensor 18. Therefore, as shown in FIG. 9B, the optical sensor 18 sequentially receives part of the laser light projected from the LD ₁ and outputs a light reception signal according to the light reception state to the integration circuit 19 ( Step S4 of FIG. 7). As shown in FIG. 9C, the integration circuit 19 integrates the voltage of the light reception signal sequentially input from the light sensor 18 over time for a predetermined period T1, and outputs the integrated value to the control unit 1 (FIG. 7). Step S5). Light emission control unit 1c, when the same LD ₁ by a predetermined number of times light emission _stops the light emission of the LD 1 to Ld ₄ for a predetermined period of time T3.

As described above, even if the integration circuit 19 integrates the light reception signal due to light emission from the same LD over time for a predetermined period T1, the integrated value becomes large. The integration period T1 of the integration circuit 19 shown in FIG. 9 is longer than the time interval T2 for causing the LD _{1 to} LD ₄ to emit light, and the time interval T2 is multiplied by the number of times of emission M of the same LD (M = 4 in this example). It is set to be shorter than the multiplication time (T2 × M) (T2 <T1 <M · T2).

  In either case of FIGS. 8 and 9, the failure diagnosis unit 1b detects the output voltage of the integration circuit 19 (step S6 of FIG. 7), and compares the output voltage with a predetermined threshold value V1. Then, if the output voltage of the integration circuit 19 is equal to or higher than the threshold value V1 (step S7 in FIG. 7: YES), the failure diagnosis unit 1b determines that there is no failure in the LD of the LD module 2 (step S8 in FIG. 7). .

  If the output voltage of the integration circuit 19 is less than the threshold value V1 (step S7 in FIG. 7: NO), the failure diagnosis unit 1b determines that there is a failure in the LD of the LD module 2 (step S9 in FIG. 7). . The failure in this case is an abnormality of the light emission output that the intensity of the laser beam projected from the LD of the LD module 2 is smaller than the prescribed intensity. In addition to the failure of the LD of the LD module 2, the failure of the LD drive circuit 3 or the failure of the light emission control unit 1 c can be considered as the cause of the abnormality.

In the case where the LD ₁ to LD ₄ are sequentially caused to emit light as shown in FIG. 8A in step S3 of FIG. 7, when the output voltage of the integration circuit 19 becomes less than the threshold V1 (FIG. Step S7: NO) The failure diagnosis unit 1b determines that at least one of the LD ₁ to LD ₄ of the LD module 2 is broken.

On the other hand, in the case where the same LD is caused to emit light a predetermined number of times as shown in FIG. 9A in step S3 of FIG. 7, when the output voltage of integration circuit 19 becomes less than threshold V1 (FIG. Step S7: NO) The failure diagnosis unit 1b determines that _one of the LD ₁ to LD ₄ of the LD module 2 which has caused light emission has failed.

  If the failure diagnosis unit 1b determines that there is a failure in the LD of the LD module 2 as described above, the failure diagnosis unit 1b outputs the diagnosis result (step S10 in FIG. 7). At this time, the failure diagnosis unit 1 b records the diagnosis result in the storage unit 11 or outputs the result to the ECU on the vehicle side through the interface 12.

After the presence or absence of a failure is diagnosed by the failure diagnosis unit 1b, the control unit 1 detects the rotation angle of the mirror 4a (step S11 in FIG. 7). Then, if the rotation angle of the mirror 4a does not reach the angle θ _{3 E} (FIG. 6, θ _{3 E} = θ ₁ + θ ₂ + θ ₃ ) at which the failure diagnosis is finished (step S12 in FIG. 7: NO), The processes after step S3 are repeated.

At the time of re-execution of step S3, in the example of FIG. 8, the light emission control unit 1c causes the LD ₁ , LD ₂ , LD ₃ , and LD ₄ to emit light sequentially at the time interval T2 again after the emission stop period T3 elapses.

Further, at the time of re-execution of step S3, in the example of FIG. 9, the light emission control unit 1c causes the same LD different from the LD emitted last time to emit light at the time interval T2 after the lapse of the light emission stop period T3. . In FIG. 9A, first, the LD ₁ emits light a predetermined number of times at the time interval T2, and then the LD ₂ emits light a predetermined number of times at the time interval T2. The next LD ₂ The following _LD 3, LD _3, as called LD _4, LD 1 ~LD ₄ sequentially to a predetermined number of times light emission (not shown). That is, in the example of FIG. 9, the light emission control unit 1c are sequentially switches the LD to emit light during the diagnosis period theta _3. Also, in the example of FIG. 9, the time it takes from the first LD ₁ to start emitting light to the end of the last LD ₄ to emit light is the mirror 4a of the scanning unit 4 during the diagnosis period θ ₃ of FIG. The time taken to rotate from the start angle _θ3S to the end angle _θ3E is set to be shorter. Therefore, light emission of each _LD 1 to Ld ₄ in diagnosis period theta ₃ is that they are executed at least once.

Then, after execution of step S3~S11 7, and reaches the angle theta _3E the rotation angle of the mirror 4a finishes the failure diagnosis (Step 7 S12: YES), the failure diagnosis operation is completed.

  In the failure diagnosis operation of FIG. 7 described above, there is shown an example in which the presence or absence of a failure of the LD module 2 is determined based on the result of comparing the output voltage of the integration circuit 19 with one threshold value V1. As in the example, the presence or absence of a failure of the LD module 2 may be determined based on the result of comparing the output voltage of the integration circuit 19 with a plurality of threshold values V1 and V2.

FIG. 10 is a flowchart showing another failure diagnosis operation of the object detection apparatus 100. When the control unit 1 detects the rotation angle of the mirror 4a (step S1 in FIG. 10) and the rotation angle reaches an angle θ 3 _S at which failure diagnosis is started (step S2 in FIG. 10: YES) The light emission process is performed (step S3 in FIG. 10), the light reception process by the light sensor 18 is performed (step S4 in FIG. 10), and the integration process by the integration circuit 19 is performed (step S5 in FIG. 10).

  Then, the failure diagnosis unit 1b detects the output voltage of the integration circuit 19 (Step S6 in FIG. 10), and compares the output voltage with a predetermined first threshold V1 and a predetermined second threshold V2. The second threshold V2 is set to a value higher than the first threshold V1.

  If the output voltage of the integration circuit 19 is equal to or more than the first threshold V1 and less than the second threshold V2 (step S7a in FIG. 10: YES), the failure diagnosis unit 1b determines that there is no failure in the LD of the LD module 2. (Step S8 in FIG. 10).

  In contrast, if the output voltage of integration circuit 19 is lower than first threshold V1 or higher than second threshold V2 (step S7a in FIG. 10: NO), failure diagnosis unit 1b determines that there is a failure in the LD of LD module 2. It judges (step S9 of FIG. 10). The failure at this time is an abnormality of the light emission output that the intensity of the laser beam projected from the LD module 2 is smaller than the prescribed intensity if the output voltage of the integration circuit 19 is less than the first threshold V1. If the output voltage V.sub.2 is greater than or equal to the second threshold value V.sub.2, it is an abnormality of the light emission output that the intensity of the laser light projected from the LD module 2 is larger than the prescribed intensity. If the failure diagnosis unit 1b determines that there is a failure in the LD of the LD module 2 as described above, the failure diagnosis unit 1b outputs the diagnosis result (step S10 in FIG. 10). In addition to the failure of the LD of the LD module 2, the failure of the LD drive circuit 3 or the failure of the light emission control unit 1 c can be considered as the cause of each abnormality described above.

If the rotation angle of the mirror 4a does not reach the angle _θ3E at which the failure diagnosis is finished after the failure diagnosis unit 1b determines the presence or absence of the failure (step S12 in FIG. 10: NO), step S3 in FIG. The subsequent processing is repeated. Then, when the rotation angle of the mirror 4a reaches the angle _θ3E at which the failure diagnosis is ended (step S12 in FIG. 10: YES), the failure diagnosis operation is ended.

  According to the embodiment described above, since the optical sensor 18 which is a light receiving element for failure diagnosis is provided separately from the APD array 7a which is a light receiving element for object detection, whether or not there is a failure of the APD array 7a Therefore, it is possible to diagnose the presence or absence of a failure of the LD module 2 or the like. Further, among the laser light projected from the LD of the LD module 2, partial light not incident on the mirror 4 a of the scanning unit 4 is condensed by the condensing guide 15 and provided in a predetermined direction other than the scanning unit 4 side The light is emitted to the light sensor 18. For this reason, the laser light projected onto the object 50 from the LD via the scanning unit 4 does not enter the light collecting guide 15, and stray light is generated in the light collecting guide 15, and the stray light is generated in the APD array 7a. It is not led to APD. Therefore, based on the light reception signal output from the APD of the APD array 7a, the object detection unit 1a can accurately detect the target 50. Furthermore, partial light not entering the scanning unit 4 is collected by the light collecting guide 15 and then received by the light sensor 18, and the light reception signal output from the light sensor 18 is further integrated by the integration circuit 19 for a predetermined period T1. Integral over Therefore, even if the intensity of the partial light is weak or the performance of the optical sensor 18 is lower than the performance of the APD array 7a, the voltage of the light reception signal of the optical sensor 18 based on the partial light is integrated circuit 19 Therefore, the level (voltage value) of the light reception signal is increased by time integration. Therefore, based on the output of the integration circuit 19, the failure diagnosis unit 1b can accurately diagnose the presence or absence of a failure of the LD module 2 or the like. . Therefore, it is possible to improve both the detection accuracy of the object 50 and the diagnosis accuracy of the failure of the LD module 2 or the like.

In the above embodiment, the condensing guide 15 condenses a part of the laser light projected from all the LD ₁ to LD ₄ provided in the LD module 2 and causes the light sensor 18 to receive the light. There is. Therefore, the light reception signal from the light sensor 18 is integrated by the integration circuit 19, and the presence or absence of failure of all the LD ₁ to LD ₄ can be detected by the failure diagnosis unit ₁ b based on the output of the integration circuit 19.

Further, in the above embodiment, the light emission control unit 1 c performs the LD ₁ to LD ₄ in the diagnosis period θ ₃ set when the scanning unit 4 does not scan the laser light projected from the LD ₁ to LD ₄ in the predetermined range. The light is emitted a plurality of times, the integration circuit 19 integrates the light reception signal from the light sensor 18, and the failure diagnosis unit 1b diagnoses the presence or absence of failure of the LD ₁ to LD ₄ based on the output of the integration circuit 19. Therefore, failure diagnosis of the LD _{1 to} LD ₄ is not performed in the scanning periods θ ₁ and θ ₅ (object detection period) in which the scanning unit 4 scans the laser light projected from the LD ₁ to LD ₄ in a predetermined range. The light emission control unit 1c can cause the LD ₁ to LD ₄ to emit light in a predetermined order and at a predetermined timing, and the laser light can be reliably irradiated to the target 50 existing in the predetermined range. Then, the reflected light from the object 50 is received by the light receiving module 7, and based on the light reception signal output from the light receiving module 7, the object detection unit 1 a accurately determines the presence or absence of the object 50 and the distance to the object 50 It becomes possible to detect well. The processing load on the control unit 1 can also be reduced by executing the failure diagnosis by the failure diagnosis unit 1b and the detection of the target 50 by the object detection unit 1a in different periods.

Further, in the embodiment of FIG. 8, since the plurality of LD ₁ to LD ₄ are sequentially emitted at the time interval T 2 in the diagnosis period θ ₃ , partial light of the laser light projected from each of the LD _{1 to} LD ₄ is Each of the light can be collected by the light collecting guide 15 and guided to the light sensor 18. Further, the integration period T1 of the light-receiving signal by the integration circuit 19, longer than the time interval T2, is set shorter than the multiplication time multiplied by the number of _LD 1 to Ld ₄ in said time interval T2. For this reason, after integrating the light reception signal sequentially output from the optical sensor 18 for a period T1 by the integration circuit 19, based on the output of the integration circuit 19, the presence or absence of failure of the LD ₁ to LD ₄ is determined by the failure diagnosis unit 1b. It is possible to diagnose at once with high accuracy.

Further, in the embodiment of FIG. 9, among the plurality of LD ₁ to Ld ₄ in diagnosis period theta _3, after the same LD at time intervals T2 for a predetermined number of times light emission is repeated sequentially switches that the LD to emit light There is. For this reason, partial light of the laser light projected from each of the LD _{1 to} LD ₄ can be condensed by the condensing guide 15 and guided to the optical sensor 18. Further, the integration period T1 of the light reception signal by the integration circuit 19 is set longer than the time interval T2 and shorter than the multiplication time obtained by multiplying the time interval T2 by the number of times of light emission of the same LD. Therefore, after light reception signals sequentially output from the light sensor 18 are integrated by the integration circuit 19 for a period T1, presence or absence of failure of each of the LD ₁ to LD ₄ by the failure diagnosis unit 1b based on the output of the integration circuit 19 Can be individually diagnosed with high accuracy.

Further, in the above embodiment, after the integration circuit 19 integrates the light reception signal from the light sensor 18 for the period T1, the light emission of the LD _{1 to} LD ₄ is stopped for the period T3 to discharge the integration circuit 19 as the discharge resistor R2. It is made to discharge. Therefore, after the time period T3 elapses, the LD _{1 to} LD ₄ are caused to emit light again, and the light collecting guide 15, the optical sensor 18, the integration circuit 19, and the failure diagnosis unit 1b again indicate the presence or absence of a failure of the LD ₁ to LD _4. It is possible to diagnose accurately.

Further, in the above embodiment, the failure diagnosis unit 1 b can accurately diagnose the presence or absence of a failure of the LD ₁ to LD ₄ based on the result of comparing the output voltage of the integration circuit 19 with a predetermined threshold value. . Particularly, in the case in the embodiment of FIG. 7, when the output voltage of the integrating circuit 19 is the threshold value V1 or more, determines that the failure of the LD ₁ to Ld ₄ is missing, the output voltage is lower than the threshold V1, LD It is determined that there is a failure of _{1 to} LD ₄ . When the intensity of the laser light projected from the LD ₁ to Ld ₄ is lower than the intensity of the provisions, the output voltage of the integration circuit 19 is less than the threshold V1, the intensity of the laser beam becomes too small LD ₁ it can detect a failure of the to Ld ₄ in fault diagnosis portion 1b.

Further, in the embodiment of FIG. 10, when the output voltage of the integration circuit 19 is not less than the threshold value V1 and less than the threshold value V2 higher than the threshold value V1, it is judged that there is no failure of the LD ₁ to LD _{4 and} the output When the voltage is lower than the threshold value V1 or higher than the threshold value V2, it is determined that there is a failure of the LD ₁ to LD ₄ . Then, when the intensity of the laser beam projected from the LD _{1 to} LD ₄ is lower than the prescribed intensity, the output voltage of the integration circuit 19 becomes less than the threshold V 1 and the intensity of the laser beam is higher than the prescribed intensity. The output voltage of the integration circuit 19 becomes equal to or higher than the threshold V2. Therefore, the failure diagnosis unit 1b can detect both the failure of the LD _{1 to} LD ₄ in which the intensity of the laser light is too low and the failure of the LD _{1 to} LD ₄ in which the intensity of the laser light is excessive. .

Furthermore, in the above embodiment, as the light receiving element for failure diagnosis, the light sensor 18 composed of a phototransistor whose response speed is slower than that of the APD array 7a for object detection is used. Nevertheless, the partial light of the laser light projected from the LD _{1 to} LD ₄ is condensed by the condensing guide 15 and is made to be received by the optical sensor 18, and the light reception signal output from the optical sensor 18 is integrated By integrating in the circuit 19, the level of the light reception signal can be increased. Therefore, based on the output of the integration circuit 19, the failure diagnosis unit 1b can accurately diagnose the presence or absence of a failure of the LD ₁ to LD ₄ . Further, compared to the APD array 7a, the phototransistor, the condensing guide 15, and the integrating circuit 19 are inexpensive, and the phototransistor is cheaper than a general photodiode. Therefore, the manufacturing cost of the object detection apparatus 100 can be reduced as compared with the case of adding a high-performance and expensive light-receiving element such as the APD array 7a for fault diagnosis.

The present invention can adopt various embodiments other than the above. For example, in the above embodiment, the light sensor 18 is formed of a phototransistor for fault diagnosis, using the APD array 7a in which a plurality of APDs are arrayed using LD ₁ to LD ₄ as light emitting elements. Although the example which showed was shown, this invention is not limited only to these. The light emitting element may be provided as appropriate in a few light emitting modules by using a light emitting element other than the LD. Also, other light receiving elements such as photodiodes may be used for object detection or failure diagnosis.

  Moreover, although the example which used the cup-shaped condensing guide 15 seen from the side was shown in the above embodiment, this invention is not limited only to this, The condensing guide of another shape is used. You may use as a condensing part.

Further, as in the embodiment shown in FIG. 8 and FIG. 9, in the diagnosis period θ ₃ , the plurality of LD ₁ to LD ₄ sequentially emit light at a predetermined time interval T 2 or the same LD is emitted at a predetermined time interval T 2 The plurality of LD ₁ to LD ₄ may emit light in an arbitrary order or at an arbitrary time interval without being limited to the example of emitting light a predetermined number of times. Further, for example, in the same diagnostic period theta _3, it may be combined emission form of the LD shown in FIG. 8 (a) and FIG. 9 (a).

Further, in the embodiment of FIG. 6, the scanning period theta ₁ is completed by the mirror surface 4a of the scanner 4, until the scan period theta ₅ by the rear surface of the mirror 4a is started, a diagnosis period theta ₃ Although the example provided is shown, the present invention is not limited to this. Other than this, for example, from the end of the scanning period theta ₅ by the rear surface of the mirror 4a, until the scan period theta ₁ by the mirror surface 4a is started, may be provided diagnosis period. Furthermore, the after the end of the scanning period theta ₁ to the start of the scanning period theta _5, both after completion of査期between theta ₅ before the start of the scanning period theta _1, it may be provided diagnosis period.

  In the above embodiment, the laser beam from the LD is scanned in a predetermined range by the scanning unit 4 having the plate-like double-sided mirror 4a, and the reflected light from the predetermined range is scanned and led to the APD array 7a. However, the present invention is not limited to this. Other than this, for example, a scanning unit in which the reflecting surface has one or more mirrors may be used. In addition, the scanning unit is designed or scanned so that the laser light from the LD is scanned in a predetermined range by the scanning unit, but the reflected light from the predetermined range is received by the APD array 7a without passing through the scanning unit. You may arrange a part or a light receiving element.

  Moreover, although the example which has arrange | positioned the condensing guide 15 and the optical sensor 18 in the transmission window 20 side of LD module 2 was shown in the above embodiment, this invention is not limited only to this. The condensing guide 15 and the light sensor 18 may be disposed, for example, on the opposite side, the upper side, the lower side, the side opposite to the light emitting surface, or the like of the LD module 2 or LD. The point is that a part of the laser light projected from the LD that does not enter the mirror 4 a of the scanning unit 4 is collected by the light collecting guide 15 and can be received by the light sensor 18. And the light sensor 18 may be arranged.

  Further, although the integration circuit 19 using the operational amplifier 19a is described as an example in the above embodiment, the present invention is not limited to this, and integration circuits of other configurations may be used. Further, the configuration of the discharge unit for discharging the integration circuit is not limited to the example shown in FIG. 5, and may be another configuration.

  Furthermore, although the example which applied this invention to the object detection apparatus 100 which consists of a laser radar for vehicles was given in the above embodiment, this invention is applied also to the object detection apparatus of another use. It is possible.

1a Object detection unit 1b Failure diagnosis unit 1c Light emission control unit 2 LD module (light emitting module)
4 scanning unit 7a APD array (first light receiving element)
15 Condenser guide (condenser part)
18 light sensor (second light receiving element)
Reference Signs List 19 integration circuit 50 target 100 target detection device LD, LD _{1 to} LD ₄ light emitting element R 2 discharge resistance (discharge portion)
T1 integration period (first period)
T2 time interval T3 emission stop period (second period)
V1 threshold, first threshold V2 second threshold Z scan angle range (predetermined range)
θ ₁ , θ ₅ object detection period θ ₃ diagnosis period

Claims (10)

A light emitting element for projecting light;
A scanning unit configured to scan a projection light projected from the light emitting element in a predetermined range;
A first light receiving element that receives the reflected light of the projected light by the object within the predetermined range, and outputs a first light receiving signal according to the light receiving state;
An object detection unit configured to detect the target based on the first light reception signal;
A condensing unit that condenses partial light that is part of the projection light and does not enter the scanning unit after being projected from the light emitting element, and emits in a predetermined direction other than the scanning unit side;
A second light receiving element which is provided on the predetermined direction side of the light collecting unit, receives light emitted from the light collecting unit, and outputs a second light receiving signal according to the light receiving state;
An integration circuit that integrates the second light reception signal over a predetermined first period;
And a fault diagnosis unit that diagnoses the presence or absence of a fault based on the output of the integration circuit. In the object detection device according to claim 1,
A light emitting module in which a plurality of the light emitting elements are arranged such that a light emitting surface of the light emitting element faces the scanning unit side;
And a light emission control unit that controls the light emission operation of the plurality of light emitting elements.
The object detection device characterized in that the condensing part condenses a part of the projection light projected from the light emitting elements. In the object detection device according to claim 2,
During a diagnosis period other than an object detection period in which the scanning unit scans the projection light to the predetermined range,
The light emission control unit causes the light emitting element to emit light a plurality of times at predetermined time intervals,
The object detection device characterized in that the integration circuit integrates the second light receiving signal sequentially output from the second light receiving element. In the object detection device according to claim 3,
The light emission control unit causes the plurality of light emitting elements to sequentially emit light at the time interval during the diagnosis period,
The object detection device according to claim 1, wherein the first period in which the integration circuit integrates the second light reception signal is longer than the time interval and shorter than a multiplication time obtained by multiplying the time interval by the number of light emitting elements. . In the object detection device according to claim 3,
The light emission control unit repeatedly causes the same light emitting element to emit light a predetermined number of times at the time interval in the diagnosis period, and then sequentially switches the light emitting elements to be emitted.
The first period during which the integration circuit integrates the second light reception signal is longer than the time interval, and shorter than a multiplication time obtained by multiplying the time interval by the number of times of light emission of the same light emitting element. Object detection device. In the object detection device according to any one of claims 1 to 5,
It further comprises a discharge unit for discharging the integration circuit,
After the integration circuit integrates the second light reception signal for the first period, the light emitting element stops emitting light for a predetermined second period, and the discharge unit discharges the integration circuit. Target detection device. The object detection device according to any one of claims 1 to 6,
The said failure diagnostic part judges the presence or absence of a failure based on the result of having compared the output voltage of the said integration circuit, and a predetermined | prescribed threshold value, The object detection apparatus characterized by the above-mentioned. In the object detection device according to claim 7,
The failure diagnosis unit determines that there is no failure if the output voltage of the integration circuit is equal to or higher than the threshold, and determines that there is a failure if the output voltage is lower than the threshold. The object detection device to be characterized. In the object detection device according to claim 7,
The threshold comprises a first threshold and a second threshold higher than the first threshold,
The failure diagnosis unit compares each of the first threshold and the second threshold with the output voltage of the integration circuit, and the output voltage is greater than or equal to the first threshold and less than the second threshold. And an object detection device characterized by judging that there is no failure, and judging that there is a failure when the output voltage is less than the first threshold or more than the second threshold. The object detection apparatus according to any one of claims 1 to 9.
The response speed of the second light receiving element is slower than the response speed of the first light receiving element.

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