WO2024043129A1 - Light source device and ranging device - Google Patents

Light source device and ranging device Download PDF

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Publication number
WO2024043129A1
WO2024043129A1 PCT/JP2023/029426 JP2023029426W WO2024043129A1 WO 2024043129 A1 WO2024043129 A1 WO 2024043129A1 JP 2023029426 W JP2023029426 W JP 2023029426W WO 2024043129 A1 WO2024043129 A1 WO 2024043129A1
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Prior art keywords
current
light emitting
light
light emission
elements
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PCT/JP2023/029426
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French (fr)
Japanese (ja)
Inventor
貴志 増田
大輔 鈴木
甲太 檜山
拓 大澤
Original Assignee
ソニーセミコンダクタソリューションズ株式会社
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Publication of WO2024043129A1 publication Critical patent/WO2024043129A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/484—Transmitters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
    • H01S5/042—Electrical excitation ; Circuits therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/068—Stabilisation of laser output parameters
    • H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters

Definitions

  • the present disclosure relates to a light source device and a distance measuring device using the light source device.
  • a light source device in which a plurality of light emitting elements are arranged in an array is used.
  • a light source device that uses a laser diode as a light emitting element is used.
  • a light source device with a high amount of light can be formed.
  • a light source device in which a drive transistor that supplies a constant current for driving is arranged for each light emitting element has been proposed (see, for example, Patent Document 1).
  • a constant light emitting current (drive current) is supplied to each drive transistor by a current mirror circuit. That is, each drive transistor and a MOS transistor constituting a current mirror circuit are arranged, and the reference current of this MOS transistor is mirrored to each drive transistor and supplied as a light emitting current.
  • the above conventional technology has a problem in that when the light emitting currents of a plurality of light emitting elements flow through the common impedance of the wiring on the source side of the driving transistor, the source potential of the driving transistor changes and the light emitting current fluctuates. This causes a problem in that the amount of light from the light source device fluctuates.
  • the present disclosure proposes a light source device and a distance measuring device that reduce changes in light amount due to changes in light emitting current of a light emitting element.
  • the light source device includes a plurality of light emitting elements, a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emitting current to flow during a light emission period, and the above by controlling the plurality of switch elements.
  • a light emission control unit that controls light emission of the plurality of light emitting elements; a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current; and a current corresponding to the light emitting current.
  • It has a light emitting current control section that supplies a control signal to the control terminals of the plurality of current limiting elements, and a light emitting current adjusting section that adjusts the light emitting current according to the number of light emitting elements to emit light among the plurality of light emitting elements. .
  • the distance measuring device of the present disclosure includes a plurality of light emitting elements, a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emitting current to flow during a light emission period, and controlling the plurality of switch elements.
  • a light emission control section that controls light emission of the plurality of light emitting elements, a plurality of current limiting elements that are arranged for each of the plurality of light emitting elements and limit the current flowing through the light emitting elements to the light emitting current; a light emission current control section that supplies a current control signal to the control terminals of the plurality of current limiting elements; and a light emission current adjustment section that adjusts the light emission current according to the number of light emitting elements to emit light among the plurality of light emitting elements.
  • a light source device comprising: a light detection element that detects reflected light from the light emitted from the light source device and reflected by the target object; and a distance measuring section that measures the distance to an object.
  • FIG. 1 is a diagram illustrating a configuration example of a light source device according to a first embodiment of the present disclosure.
  • FIG. 3 is a diagram illustrating fluctuations in light emitting current according to an embodiment of the present disclosure.
  • FIG. 3 is a diagram illustrating a configuration example of a light emitting current adjustment section according to a first embodiment of the present disclosure.
  • FIG. 3 is a diagram illustrating an example of an adjustment current according to the first embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a configuration example of a light source device according to a second embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating an example of an adjustment current according to a second embodiment of the present disclosure.
  • FIG. 7 is a diagram showing another example of the adjustment current according to the second embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating an example of a region according to a second embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating an example of a region according to a second embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating an example of a region according to a second embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a configuration example of a light source device according to a third embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating an example of an adjustment current according to a third embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a configuration example of a light source device according to a fourth embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a configuration example of a light emitting current adjustment section according to a fourth embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a configuration example of a light emission control section according to a fourth embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a configuration example of a light emission signal generation circuit according to a fourth embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating an example of generation of a light emission signal according to a fourth embodiment of the present disclosure.
  • FIG. 7 is a diagram illustrating a configuration example of a light source device according to a fifth embodiment of the present disclosure. It is a figure showing the example of composition of the light source device concerning the 1st modification of the embodiment of this indication.
  • FIG. 1 is a diagram illustrating a configuration example of a light emitting element according to an embodiment of the present disclosure.
  • FIG. 3 is a diagram illustrating another configuration example of a light emitting element according to an embodiment of the present disclosure.
  • FIG. 2 is a diagram illustrating an example of light emission from a light emitting element according to an embodiment of the present disclosure.
  • FIG. 2 is a diagram illustrating an example of light emission from a light emitting element according to an embodiment of the present disclosure.
  • 1 is a diagram illustrating a configuration example of a distance measuring device to which a light source device according to an embodiment of the present disclosure can be applied.
  • FIG. 1 is a diagram illustrating a configuration example of a light source device according to a first embodiment of the present disclosure. This figure is a block diagram showing an example of the configuration of the light source device 10.
  • the light source device 10 includes a plurality (n) of light emitting elements 101 to 103, a plurality (n) of switch elements 121 to 123, a plurality (n) of current limiting elements 111 to 113, and a MOS transistor 124.
  • a light emission control section 20 is provided.
  • the light source device 10 further includes a light emission current adjustment section 30, a light emission current control section 40, and a control section 50.
  • the light emitting elements 101 to 103 are semiconductor elements that emit light by flowing a light emitting current.
  • a laser diode can be used as the light emitting element 101 and the like.
  • the switch elements 121 to 123 are elements that are connected in series to each of the plurality of light emitting elements 101 to 103 and allow a light emitting current to flow during the light emitting period.
  • N-channel MOS transistors can be used for the switch elements 121 to 123.
  • the current limiting elements 111 to 113 are elements arranged for each of the plurality of light emitting elements 101 to 103 to limit the current flowing through the light emitting elements 101 to 103 to the light emitting current.
  • N-channel MOS transistors can be used for current limiting elements 111 to 113.
  • the light emitting current control section 40 supplies a current control signal according to the light emitting current to the control terminals of the plurality of current limiting elements 111 to 113. Note that the gates of the current limiting elements 111 to 113 correspond to control terminals.
  • This light emitting current control section 40 includes a constant current circuit 130 and a MOS transistor 114.
  • the circuit connections of the light source device 10 will be explained.
  • the anode of the light emitting element 101 is connected to a power line Vdd that supplies power, and the cathode of the light emitting element 101 is connected to the drain of the current limiting element 111.
  • the source of current limiting element 111 is connected to the drain of switch element 121, and the source of switch element 121 is grounded. In this way, the light emitting element 101, the current limiting element 111, and the switching element 121 connected in series are connected between the power supply line Vdd and the ground line. Similar connections are made in the light emitting element 102, current limiting element 112, and switch element 122, as well as in the light emitting element 103, current limiting element 113, and switch element 123.
  • a node of the light emitting element 101, current limiting element 111, and switch element 121 connected in series is hereinafter referred to as a light emitting element node.
  • n light emitting element nodes are arranged in the light source device 10. Note that the gates of the switch elements 121 to 123 are connected to the output of the light emission current control section 40, respectively.
  • the sink side terminal of the constant current circuit 130 of the light emitting current control section 40 is connected to the power supply line Vdd, and the source side terminal is connected to the drain and gate of the MOS transistor 114 and the gates of the current limiting elements 111 to 113.
  • the source of MOS transistor 114 is connected to the drain of MOS transistor 124, and the source of MOS transistor 124 is grounded.
  • the gate of MOS transistor 124 is connected to power supply line Vdd.
  • the MOS transistor 114 of the light emitting current control section 40 and the current limiting elements 111 to 113 constitute a current mirror circuit. That is, the reference current, which is the current flowing through the MOS transistor 114, is mirrored by the current limiting elements 111 to 113.
  • the MOS transistor 124 is an element connected to obtain a voltage drop equivalent to that of the switch element 121. Therefore, the mirror ratio of the current mirror circuit is 1:1. For example, by making the switch elements 121 to 123 conductive, the sources of the current limiting elements 111 to 113 and the ground line are approximately short-circuited. Therefore, currents equal to the reference current of constant current circuit 130 flow through current limiting elements 111 to 113, respectively. This current becomes a light emitting current.
  • a desired light emitting element can be caused to emit light.
  • the reference current of the constant current circuit 130 is controlled by a light emitting current adjustment section 30, which will be described later.
  • the light source device 10 in the figure represents an example in which the light emitting elements 101 to 103 and the light emitting current control unit 40 are connected to the same power source (power line Vdd), but the circuit configuration of the light emitting element 101 etc. is not limited to this example.
  • different power supplies may be connected to the light emitting elements 101 to 103 and the light emitting current control section 40.
  • power supplies with different voltages can be supplied to the light emitting elements 101 to 103 and the light emitting current control unit 40.
  • the mirror ratio of the current mirror circuit constituted by the MOS transistor 114 of the light emission current control section 40 and the current limiting elements 111 to 113 can be set to different values.
  • the mirror ratio can be set to 1:N.
  • power consumption of the light emitting current control section 40 and the like can be reduced.
  • the aspect ratio of the switch elements 121 to 123 with respect to the MOS transistor 124 must also be increased by N times.
  • the light emission control unit 20 controls the light emission of the plurality of light emitting elements 101 to 103 by controlling the plurality of switch elements 121 to 123.
  • This light emission control section 20 controls the switching elements 121 to 123 by individually turning them on.
  • the light emission control section 20 outputs ON signals for the MOS transistors forming the switch elements 121 to 123.
  • This on signal is a signal with a voltage higher than the gate-source voltage Vgs that turns the MOS transistor into a conductive state.
  • the switch element 121 and the like to which this ON signal is applied to the gate become conductive.
  • a drive signal and a light emission pattern are input to the light emission control section 20.
  • the drive signal is a signal indicating the timing to cause the light emitting elements 101 to 103 to emit light, and is a signal indicating the timing to make the switch elements 121 to 123 conductive.
  • the light emission pattern is a signal indicating which light emitting element to emit light among the light emitting elements 101 to 103.
  • the light emission control unit 20 selects the switch elements 121 to 123 based on the light emission pattern, and outputs an ON signal to the selected switch elements 121 to 123 at a timing based on the drive signal.
  • the light emission current adjustment section 30 controls the light emission current of the light emission current control section 40. Specifically, the light emitting current adjustment section 30 controls the constant current circuit 130 of the light emitting current control section 40 to flow a reference current corresponding to the light emitting current. Further, the light emitting current adjustment unit 30 further adjusts the light emitting current according to the number of light emitting elements to emit light among the plurality of light emitting elements 101 to 103. As will be described later, the light emitting current of the current limiting elements 111 to 113 that constitute the current mirror circuit changes depending on the number of light emitting elements. The light emitting current adjustment section 30 adjusts the light emitting current in order to compensate for this change in the light emitting current. Details of the configuration of the light emitting current adjustment section 30 will be described later.
  • the control unit 50 controls the entire light source device 10.
  • the control section 50 generates a current control signal, a light emission pattern, and a drive signal based on instructions from an external device, and outputs them to the light emission current adjustment section 30 and the light emission control section 20.
  • FIG. 2 is a diagram illustrating fluctuations in light emitting current according to the embodiment of the present disclosure.
  • This figure is a diagram illustrating the circuit portions of the light emitting elements 101 to 103 in FIG. 1.
  • I0 represents the current (reference current) of the MOS transistor 114.
  • I 1 to I n represent the light emission currents of the current limiting elements 111 to 113.
  • the figure also shows the parasitic resistances of the source-side wiring of the MOS transistor 114 and the current limiting elements 111 to 113 that constitute the current mirror circuit.
  • the resistor indicated by the broken line in the figure corresponds to the parasitic resistance.
  • wiring has parasitic resistance based on wiring resistance.
  • parasitic resistances 301 and 302 are present in the source side wiring of the current limiting element 111.
  • the parasitic resistances 301 and 302 are different from the parasitic resistance of the MOS transistor 114, the effective gate-source voltages Vgs of the current limiting element 111 and the MOS transistor 114 are different, so that the light emitting current I1 of the current limiting element 111 is limited by the current limit.
  • the current I of the element 111 has a value different from 0 .
  • parasitic resistance in the grounding wire There is also parasitic resistance in the grounding wire.
  • a parasitic resistance through which a plurality of light emitting currents commonly flow is called a common impedance.
  • the parasitic resistance 303 in the figure corresponds to a common impedance through which the light emitting currents I 1 to I n flow.
  • the voltage drop across the parasitic resistor 303, which serves as this common impedance changes depending on the flowing light emitting current. That is, the voltage drop across the parasitic resistance 303 changes depending on the number of light emitting elements 101 to 103. Therefore, in the current limiting element 111 where the light emitting current I1 flows through the parasitic resistance 303, the effective gate-source voltage Vgs changes due to the light emitting current from other light emitting element nodes, and the light emitting current fluctuates.
  • the light emitting current I 1 of the light emitting element 101 is approximately equal to I 0 .
  • the voltage drop across the parasitic resistance 303 increases and the effective gate-source voltage Vgs decreases, so that the light emitting current I 1 is lower than I 0 . In this way, the light emitting current changes depending on the number of light emitting elements among the light emitting elements 101 to 103.
  • the light emitting current adjustment section 30 performs an operation to compensate for this change in light emitting current.
  • FIG. 3 is a diagram illustrating a configuration example of a light emission current adjustment section according to the first embodiment of the present disclosure.
  • This figure is a block diagram showing an example of the configuration of the light emitting current adjustment section 30.
  • the light emitting current adjusting section 30 in the figure includes a light emitting element number detecting section 31, a drive adjusting section 32, and an adjusted current holding section 33.
  • the light emitting element number detection unit 31 detects the number of light emitting elements based on a light emission pattern.
  • the light emitting element number detection section 31 outputs the number of light emitting elements to the drive adjustment section 32.
  • the drive adjustment section 32 controls the flow of a reference current through the constant current circuit 130 of the light emitting current adjustment section 30 based on the current control signal. Further, the drive adjustment section 32 further performs control to adjust the reference current of the constant current circuit 130 based on the number of light emitting elements from the light emitting element number detection section 31. The drive adjustment section 32 adjusts the reference current based on the adjustment current of the adjustment current holding section 33.
  • the adjustment current holding unit 33 holds information on the adjustment current for adjusting the reference current.
  • the adjustment current holding unit 33 includes a table showing the correspondence between the number of light emitting elements and the adjustment current.
  • FIG. 4 is a diagram illustrating an example of the adjustment current according to the first embodiment of the present disclosure.
  • This figure is a diagram showing an example of the adjustment current held in the adjustment current holding section 33.
  • the number of light emitting elements in the figure represents the number of light emitting elements among the light emitting elements 101 to 103.
  • This figure shows a case where there are 10 light emitting elements (light emitting element nodes).
  • the adjusted current in the figure represents the adjusted value of the light emitting current.
  • the adjustment current in the figure is based on the case where the number of light emitting elements is 10, and represents an example in which the value increases as the number of light emitting elements decreases. Specifically, when the number of light emitting elements is "1", the adjustment current is "-5%".
  • the drive adjustment unit 32 performs an adjustment to reduce the light emitting current (reference current) by 5% when the number of light emitting elements is "10".
  • the drive adjustment section 32 controls the constant current circuit 130 to flow the adjusted reference current. Thereby, the value of the light emitting current is adjusted according to the number of light emitting elements.
  • the light source device 10 of the first embodiment of the present disclosure adjusts the light emitting current of the light emitting elements 101 to 103 according to the number of light emitting elements. Thereby, fluctuations in the light emitting currents of the light emitting elements 101 to 103 can be reduced, and fluctuations in the amount of light from the light source device 10 can be reduced.
  • the light source device 10 of the first embodiment described above a plurality of light emitting elements are arranged.
  • the light source device 10 according to the second embodiment of the present disclosure differs from the above-described first embodiment in that a plurality of light emitting elements are divided into a plurality of regions.
  • FIG. 5 is a diagram illustrating a configuration example of a light source device according to a second embodiment of the present disclosure.
  • This figure like FIG. 1, is a diagram showing a configuration example of the light source device 10.
  • the light source device 10 in the figure differs from the light source device 10 in FIG. 1 in that the light emitting element node is divided into a plurality of regions.
  • the light source device 10 in the figure includes a region 100 consisting of light emitting element nodes of light emitting elements 101 to 103 and a region 150 consisting of light emitting element nodes of light emitting elements 151 to 153.
  • the region 150 includes light emitting elements 151 to 153, current limiting elements 161 to 163, and switching elements 171 to 173. These light emitting elements 151 to 153 each constitute a light emitting element node.
  • the region 150 in the figure represents an example including the same number of light emitting element nodes as the region 100.
  • current limiting elements 161 to 163 in region 150 constitute a current mirror circuit with MOS transistor 114. A configuration including such areas 100 and 150 is applied when a plurality of light emitting elements 101 and the like are divided by hardware.
  • FIG. 6 is a diagram illustrating an example of the adjustment current according to the second embodiment of the present disclosure.
  • This figure like FIG. 4, is a diagram showing an example of the adjustment current held in the adjustment current holding section 33.
  • "Region #1" and “Region #2” in the figure represent the number of light emitting elements in regions 100 and 150, respectively. In regions 100 and 150, when the number of light emitting elements is "5", the adjustment value is the smallest (the absolute value is the largest).
  • FIG. 7 is a diagram showing another example of the adjustment current according to the second embodiment of the present disclosure.
  • This figure like FIG. 6, is a diagram showing an example of the adjustment current held in the adjustment current holding section 33.
  • the figure shows an example in which the adjustment value is changed depending on the light emitting current.
  • the adjustment current at the left end of the figure represents the adjustment current when the light emitting current is low (low light amount).
  • the adjustment current in the center of the figure represents the adjustment current in the case of an intermediate light emission current.
  • the adjustment current at the right end of the figure represents the adjustment current when the light emission current is large (when the amount of light is high).
  • the adjustment value can be increased. This is because the voltage drop across the parasitic resistance 303, which is a common impedance, increases.
  • FIGS. 8A-8C are diagrams illustrating examples of regions according to the second embodiment of the present disclosure.
  • the rectangles in the figure represent the light emitting elements 101 and the like.
  • light emitting elements 101 and the like are arranged in a two-dimensional matrix.
  • the white rectangles in the figure represent light-emitting elements included in the region 100
  • the hatched rectangles represent light-emitting elements contained in the region 150.
  • FIG. 8A shows an example in which a plurality of light emitting elements 101 etc. are equally divided into two rectangular regions 100 and 150.
  • FIG. 8B shows an example in which the outer light emitting elements of the plurality of light emitting elements 101 and the like are arranged in the region 150, and the inner light emitting elements are arranged in the region 100.
  • FIG. 8C shows an example in which a plurality of light emitting elements 101 and the like are alternately distributed to regions 100 and 150 for each column.
  • the configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
  • the light source device 10 of the second embodiment of the present disclosure when a plurality of light emitting elements 101, etc. are divided into a plurality of regions 100, etc., the light emitting elements 101 to 103, etc. are divided according to the number of light emitting elements. Adjust the emission current.
  • the light source device 10 of the second embodiment described above the plurality of light emitting elements 101 and the like are divided into regions 100 and 150.
  • the light source device 10 according to the third embodiment of the present disclosure differs from the above-described second embodiment in that a current mirror circuit such as the current limiting element 161 is configured for each divided region.
  • FIG. 9 is a diagram illustrating a configuration example of a light source device according to a third embodiment of the present disclosure.
  • This figure like FIG. 5, is a diagram showing a configuration example of the light source device 10.
  • the light source device 10 in the figure differs from the light source device 10 in FIG. 5 in that different current mirror circuits are arranged in regions 100 and 150.
  • the light source device 10 in the figure further includes a constant current circuit 131 and MOS transistors 164 and 174. Note that the constant current circuit 131 and the MOS transistor 164 constitute the light emitting current control section 41.
  • the sink side terminal of the constant current circuit 131 of the light emitting current control section 41 is connected to the power supply line Vdd, and the source side terminal is connected to the drain and gate of the MOS transistor 164 and the gates of the current limiting elements 161 to 163.
  • the source of MOS transistor 164 is connected to the drain of MOS transistor 174, and the source of MOS transistor 174 is grounded.
  • the gate of MOS transistor 174 is connected to power supply line Vdd.
  • the light emitting current adjustment section 30 (not shown) of the light source device 10 in the figure adjusts the light emitting current of the plurality of light emitting current control sections 40 and 41.
  • FIG. 10 is a diagram illustrating an example of the adjustment current according to the third embodiment of the present disclosure.
  • This figure like FIG. 6, is a diagram showing an example of the adjustment current held in the adjustment current holding section 33.
  • the adjusted current holding unit 33 according to the third embodiment of the present disclosure holds the adjusted current for each region 100 and 150.
  • the light emitting current adjustment section 30 can adjust the light emitting current for each of the regions 100 and 150. For example, even if the arrangement of the parasitic resistance, which is a common impedance, differs greatly from region to region, as in regions 100 and 150 in FIG. 8B, the light emitting current can be compensated for each region 100 and 150.
  • the configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the second embodiment of the present disclosure, so the description will be omitted.
  • the light source device 10 includes the light emission current control units 40 and 41 for each of the regions 100 and 150. Thereby, fluctuations in the light emitting current can be further reduced.
  • the light source device 10 of the first embodiment described above adjusts the light emitting current by adjusting the light emitting current value.
  • the light source device 10 according to the fourth embodiment of the present disclosure differs from the above-described first embodiment in that the light emitting current is adjusted by adjusting the period in which the light emitting current flows.
  • FIG. 11 is a diagram illustrating a configuration example of a light source device according to a fourth embodiment of the present disclosure. This figure, like FIG. 1, is a diagram showing a configuration example of the light source device 10. The light source device 10 shown in FIG. 1 differs from the light source device 10 shown in FIG. .
  • the light emitting current adjustment section 30 in the figure does not need to adjust the light emitting current (reference current) of the light emitting current control section 40. Instead, the light emission current adjustment section 30 in the figure outputs a light emission period adjustment signal to the light emission control section 20.
  • This light emission period adjustment signal is a signal that adjusts the light emission period according to the number of light emitting elements.
  • the light emission control section 20 in the figure outputs a pulse-like ON signal whose light emission period is adjusted based on the light emission period adjustment signal to the switch elements 121 to 123.
  • FIG. 12 is a diagram illustrating a configuration example of a light emission current adjustment section according to a fourth embodiment of the present disclosure. Similar to FIG. 3, this figure is a block diagram showing a configuration example of the light emitting current adjustment section 30.
  • the light emitting current adjusting section 30 shown in the figure is different from the light emitting current adjusting section 30 shown in FIG. 3 in that it further includes a reference current controlling section 34, and the drive adjusting section 32 generates and outputs a light emitting period adjustment signal.
  • the reference current control unit 34 controls the flow of a reference current to the constant current circuit 130 of the light emitting current control unit 40 based on the current control signal.
  • the drive adjustment section 32 in the figure generates a light emission period adjustment signal based on the number of light emitting elements from the light emitting element number detection section 31.
  • This light emission period adjustment signal is input to a delay circuit 221 of a light emission signal generation circuit 22 of a light emission control section 20, which will be described later.
  • the light emission period adjustment signal is a signal that indicates the delay time of the delay circuit 221.
  • FIG. 13 is a diagram illustrating a configuration example of a light emission control section according to a fourth embodiment of the present disclosure.
  • This figure is a block diagram showing a configuration example of the light emission control section 20.
  • the light emission control section 20 in the figure includes a non-inverting buffer 21, a light emission signal generation circuit 22, a light emitting element selection section 23, and a plurality of gate drive circuits 24.
  • the non-inverting buffer 21 corresponds to a buffer amplifier and amplifies the drive signal and outputs it to the light emission signal generation circuit 22.
  • the light emission signal generation circuit 22 is a circuit that generates a pulsed light emission signal based on a drive signal inputted via the non-inverting buffer 21. Furthermore, the light emission signal generation circuit 22 further adjusts the Hals width of the light emission signal based on the light emission period adjustment signal from the light emission current adjustment section 30. Details of the configuration of the light emission signal generation circuit 22 will be described later.
  • the light emitting element selection unit 23 selects the light emitting element 101 etc. to emit light based on the light emitting pattern, and outputs a light emitting signal to the light emitting element node of the selected light emitting element 101 etc.
  • the gate drive circuit 24 is arranged for each light emitting element node, and generates and outputs a pulsed ON signal based on the light emission signal from the light emitting element selection section 23.
  • FIG. 14A is a diagram illustrating a configuration example of a light emission signal generation circuit according to a fourth embodiment of the present disclosure. This figure is a block diagram showing a configuration example of the light emission signal generation circuit 22. As shown in FIG. The light emission signal generation circuit 22 in the figure includes a delay circuit 221 and an AND gate 222.
  • the delay circuit 221 is a circuit that delays the drive signal based on the light emission period adjustment signal.
  • the AND gate 222 is a gate that performs an AND operation of the drive signal and the drive signal delayed by the delay circuit 221. The output of the AND gate 222 corresponds to the light emission signal.
  • FIG. 14B is a diagram illustrating an example of generation of a light emission signal according to the fourth embodiment of the present disclosure.
  • Drive signal in the figure represents the waveform of the drive signal.
  • delay circuit output in the figure represents the waveform of the output signal of the delay circuit 221.
  • light emission signal in the figure represents the waveform of the light emission signal that is the output signal of the AND gate 222.
  • a signal with a pulse width of 2 ns is assumed as the drive signal.
  • the waveform of the delay circuit output in the figure represents an example in which the delay circuit 221 delays the drive signal by 1 ns.
  • a light emission signal can be generated by performing an AND operation on these two signal waveforms. As shown in the figure, this light emission signal is a signal whose pulse width changes according to the delay time of the delay circuit 221.
  • the light emission current adjustment section 30 of the fourth embodiment of the present disclosure outputs a light emission period adjustment signal according to the number of light emitting elements.
  • This light emission period adjustment signal is, for example, a signal instructing a delay time at which the pulse width corresponds to the adjustment value shown in FIG. 4.
  • This light emission period adjustment signal is input to the delay circuit 221, and the pulse width of the light emission signal is adjusted. For example, when the number of light emitting elements is "1", adjustment is made to reduce the pulse width of the light emission signal by 5%. Thereby, the total sum (integrated value) of the light amount of the light source device 10 during the light emission period can be equalized.
  • the configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
  • the light source device 10 adjusts the light emission period according to the number of light emitting elements such as the light emitting element 101. This makes it possible to reduce changes in the total amount of light during the light emission period.
  • FIG. 15 is a diagram illustrating a configuration example of a light source device according to a fifth embodiment of the present disclosure. This figure, like FIG. 1, is a diagram showing a configuration example of the light source device 10.
  • the light source device 10 shown in FIG. 1 differs from the light source device 10 shown in FIG. 1 in that it further includes an overcurrent detection section 60 and a threshold value adjustment section 70.
  • the overcurrent detection section 60 includes resistors 63 and 64, MOS transistors 61 and 62, a constant current circuit 65, and a comparator 66.
  • MOS transistors 61 and 62 can be n-channel MOS transistors.
  • One end of the resistor 63 is connected to the power supply line Vdd, and the other end is connected to the drain of the MOS transistor 61 and the comparison input of the comparator 66.
  • the source of MOS transistor 61 is connected to the drain of MOS transistor 62, and the source of MOS transistor 62 is grounded.
  • the gate of MOS transistor 61 is connected to the drain of MOS transistor 14, and the gate of MOS transistor 62 is connected to power supply line Vdd.
  • One end of the resistor 64 is connected to the power supply line Vdd, and the other end is connected to the sink side terminal of the constant current circuit 65 and the reference input of the comparator 66.
  • the source side terminal of the constant current circuit 65 is grounded.
  • the constant current circuit 65 is a circuit that supplies a constant current based on a control signal from the threshold value adjustment section 70.
  • the potential of the sink side terminal of the constant current circuit 65 becomes a threshold voltage for overcurrent detection.
  • the potential of the drain of the MOS transistor 61 is a potential corresponding to the light emitting current.
  • the comparator 66 compares the threshold voltage input to the reference input and the voltage corresponding to the light emission current input to the comparison input, and detects an overcurrent when the voltage according to the light emission current exceeds the threshold voltage, Outputs a detection signal. In this way, the overcurrent detection section 60 shown in the figure indirectly detects overcurrent of the light emitting element 101 and the like.
  • the threshold value adjustment unit 70 detects the number of light emitting elements such as the light emitting element 101 based on the light emission pattern, and adjusts the threshold value.
  • the light emitting current adjustment section 30 described above adjusts the light emitting current according to the number of light emitting elements such as the light emitting element 101. Therefore, by arranging the threshold value adjusting section 70 and adjusting the threshold value according to the number of light emitting elements such as the light emitting element 101, it is possible to improve the accuracy of overcurrent detection.
  • the configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
  • the light source device 10 includes the overcurrent detection section 60 and detects an overcurrent of the light emitting current of the light emitting element 101 and the like. Further, the threshold value for overcurrent detection is adjusted according to the number of light emitting elements such as the light emitting element 101. Thereby, even when the light emitting current is adjusted according to the number of light emitting elements, the accuracy of overcurrent detection can be improved.
  • FIG. 16 is a diagram illustrating a configuration example of a light source device according to a first modification of the embodiment of the present disclosure.
  • This figure like FIG. 1, is a diagram showing a configuration example of the light source device 10.
  • the light source device 10 shown in the figure represents an example in which the switching elements 121 to 123 and the current limiting elements 111 to 113 shown in FIG. 1 are wired with the connection order reversed. Accordingly, the MOS transistors 114 and 124 are also wired interchangeably.
  • FIG. 17 is a diagram illustrating a configuration example of a light source device according to a second modification of the embodiment of the present disclosure.
  • This figure like FIG. 1, is a diagram showing a configuration example of the light source device 10.
  • the light source device 10 shown in the figure represents an example in which switching elements 125 to 127 and current limiting elements 115 to 117 of p-channel MOS transistors are used. Further, p-channel MOS transistors are also used for the MOS transistor 118 of the light emission current control section 40 and the MOS transistor 128 connected to the source of the MOS transistor 118.
  • the configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
  • FIG. 18A is a diagram illustrating a configuration example of a light emitting element according to an embodiment of the present disclosure. This figure is a diagram illustrating a configuration example of a light emitting element chip 400 having a light emitting element array 410 configured by a plurality of light emitting elements arranged in an array.
  • the light emitting element array 410 is composed of laser diodes 411, which are light emitting elements, arranged in a two-dimensional matrix.
  • a vertical cavity surface emitting laser (VCSEL) can be applied to the laser diode 411. Black circles on both sides of this laser diode 411 represent connection terminals 412.
  • the light emitting element array 410 is mounted on the light emitting element chip 400. Circuits other than the light emitting elements 101 to 103 in FIG. 1 can be arranged in this light emitting element chip 400.
  • a pad 401 is arranged at an end of the light emitting element chip 400. The pad 401 and the connection terminal 412 can be connected by a bonding wire.
  • FIG. 18B is a diagram illustrating another configuration example of the light emitting element according to the embodiment of the present disclosure. This figure shows an example in which a light emitting element array 410 is connected to a light emitting element chip 400 via bumps 413 arranged on the back surface thereof.
  • Example of light emission of light emitting element 19A and 19B are diagrams illustrating an example of light emission of a light emitting element according to an embodiment of the present disclosure. This figure is a diagram showing an example of light emission from the light emitting element array 410. In the figure, a diagonally hatched laser diode 411 represents the laser diode 411 in a light emitting state.
  • FIG. 19A shows an example in which adjacent laser diodes 411 are caused to emit light. Further, FIG. 19B shows an example in which the laser diodes 411 that emit light are dispersed.
  • FIG. 20 is a diagram illustrating a configuration example of a distance measuring device to which the light source device according to the embodiment of the present disclosure can be applied.
  • This figure is a diagram showing an example of the configuration of a distance measuring device 700.
  • the distance measuring device 700 is a device that measures the distance to an object.
  • a distance measuring device 700 in the figure represents an example of measuring the distance to an object 701.
  • the distance measuring device 700 includes a light source device 710, a light detection element 720, a distance measuring section 730, and a control section 740. Note that the white arrows in the figure represent the transmission of light.
  • emitted light 702 emitted from a light source device 710 of a distance measuring device 700 is reflected by an object 701 to generate reflected light 703.
  • This reflected light 703 reaches the distance measuring device 700 and is detected by the photodetecting element 720.
  • the time (flight time) from the emission of the emitted light 702 to the detection of the reflected light 703 can be measured.
  • the light source device 710 irradiates light onto the object to be measured. Note that the above-described light source device 10 can be applied to the light source device 710.
  • the photodetector element 720 includes a plurality of pixels that generate image signals according to incident light.
  • This photodetecting element 720 can be configured by, for example, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor.
  • the photodetecting element 720 images the reflected light 703 received during a period synchronized with the light emitting period and the non-emitting period of the emitted light 702, and generates an image signal.
  • Photodetection element 720 outputs the generated image signal to distance measuring section 730.
  • the distance measuring unit 730 measures the distance to the object 701.
  • the distance measuring section 730 measures the distance by measuring the flight time described above based on the image signal output from the photodetecting element 720.
  • the distance measured by the distance measuring unit 730 is output to the outside of the distance measuring device 700 as distance data.
  • the control unit 740 controls the entire distance measuring device 700. For example, the control unit 740 instructs the light source device 710 to emit light, and notifies the ranging unit 730 of the start of light emission. In response to this notification, the ranging section 730 starts measuring the flight time. Further, the control unit 740 controls the photodetection element 720, such as generation of an image signal. The control unit 740 controls the light source device 710 and the like by outputting a control signal.
  • the present technology can also have the following configuration. (1) multiple light emitting elements; a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emission current to flow during a light emission period; a light emission control unit that controls light emission of the plurality of light emitting elements by controlling the plurality of switch elements; a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current; a light emission current control unit that supplies a current control signal according to the light emission current to control terminals of the plurality of current limiting elements; and a light emitting current adjustment section that adjusts the light emitting current according to the number of light emitting elements that emit light among the plurality of light emitting elements.
  • the light source device adjusts the light emission by adjusting the value of the light emission current in the light emission current control section.
  • the current limiting element is constituted by a MOS transistor whose gate is the control terminal,
  • the light emission current control unit includes a MOS transistor forming a current mirror circuit with the plurality of current limiting elements, and supplies a gate voltage of the MOS transistor to the plurality of current limiting elements as the current control signal,
  • multiple light emitting elements a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emission current to flow during a light emission period; a light emission control unit that controls light emission of the plurality of light emitting elements by controlling the plurality of switch elements; a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current; a light emission current control unit that supplies a current control signal according to the light emission current to control terminals of the plurality of current limiting elements; a light source device comprising: a light emitting current adjustment section that adjusts the light emitting current according to the number of light emitting elements to emit light among the plurality of light emitting elements; a photodetection element that detects reflected light emitted from the light source device and reflected by a target object; A distance measuring device, comprising: a distance measuring section that measures a distance to the object by measuring a time from emission of the

Abstract

The present invention reduces a change in light quantity caused by a change in light-emitting current of a light-emitting element. This light source device comprises: a plurality of light-emitting elements; a plurality of switch elements that are connected in series for the respective light-emitting elements and that supply light-emitting current during a light emission period; a light emission control unit that controls light emission of the plurality of light-emitting elements by controlling the plurality of switch elements; a plurality of current limitation elements that are disposed for the respective light-emitting elements and that limit current for flowing through the light-emitting elements to the current-emitting current; a light-emitting current control unit that supplies a current control signal corresponding to the light-emitting current to control terminals of the plurality of current limitation elements; and a light-emitting current adjustment unit that adjusts the light-emitting current in accordance with the number of light-emitting elements that emit light among the plurality of light-emitting elements.

Description

光源装置及び測距装置Light source device and ranging device
　本開示は、光源装置及び当該光源装置を使用する測距装置に関する。 The present disclosure relates to a light source device and a distance measuring device using the light source device.
　複数の発光素子がアレイ状に配置されて構成された光源装置が使用されている。例えば、レーザダイオードを発光素子として使用する光源装置が使用されている。高出力のレーザダイオードをアレイ状に配置することにより高光量の光源装置を形成することができる。このような光源装置において、駆動のための定電流を供給する駆動トランジスタが発光素子毎に配置される光源装置が提案されている（例えば、特許文献１参照）。 A light source device in which a plurality of light emitting elements are arranged in an array is used. For example, a light source device that uses a laser diode as a light emitting element is used. By arranging high-output laser diodes in an array, a light source device with a high amount of light can be formed. Among such light source devices, a light source device in which a drive transistor that supplies a constant current for driving is arranged for each light emitting element has been proposed (see, for example, Patent Document 1).
　この光源装置では、カレントミラー回路によりそれぞれの駆動トランジスタに一定の発光電流（駆動電流）を供給する。すなわち、それぞれの駆動トランジスタとカレントミラー回路を構成するＭＯＳトランジスタとが配置され、このＭＯＳトランジスタの参照電流がそれぞれの駆動トランジスタにミラーされ、発光電流として供給される。 In this light source device, a constant light emitting current (drive current) is supplied to each drive transistor by a current mirror circuit. That is, each drive transistor and a MOS transistor constituting a current mirror circuit are arranged, and the reference current of this MOS transistor is mirrored to each drive transistor and supplied as a light emitting current.
特開２０２０－０４３２２９号公報Japanese Patent Application Publication No. 2020-043229
　しかしながら、上記の従来技術では、駆動トランジスタのソース側の配線の共通インピーダンスに複数の発光素子の発光電流が流れる場合に駆動トランジスタのソース電位が変化し、発光電流が変動するという問題がある。このため、光源装置の光量が変動するという問題を生じる。 However, the above conventional technology has a problem in that when the light emitting currents of a plurality of light emitting elements flow through the common impedance of the wiring on the source side of the driving transistor, the source potential of the driving transistor changes and the light emitting current fluctuates. This causes a problem in that the amount of light from the light source device fluctuates.
　そこで、本開示では、発光素子の発光電流の変化による光量の変化を低減する光源装置及び測距装置を提案する。 Therefore, the present disclosure proposes a light source device and a distance measuring device that reduce changes in light amount due to changes in light emitting current of a light emitting element.
　本開示に係る光源装置は、複数の発光素子と、上記複数の発光素子毎に直列に接続されて発光期間に発光電流を流す複数のスイッチ素子と、上記複数のスイッチ素子を制御することにより上記複数の発光素子の発光を制御する発光制御部と、上記複数の発光素子毎に配置されて発光素子に流れる電流を上記発光電流に制限する複数の電流制限素子と、上記発光電流に応じた電流制御信号を上記複数の電流制限素子の制御端子に供給する発光電流制御部と、上記複数の発光素子のうちの発光させる発光素子数に応じて上記発光電流を調整する発光電流調整部とを有する。 The light source device according to the present disclosure includes a plurality of light emitting elements, a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emitting current to flow during a light emission period, and the above by controlling the plurality of switch elements. a light emission control unit that controls light emission of the plurality of light emitting elements; a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current; and a current corresponding to the light emitting current. It has a light emitting current control section that supplies a control signal to the control terminals of the plurality of current limiting elements, and a light emitting current adjusting section that adjusts the light emitting current according to the number of light emitting elements to emit light among the plurality of light emitting elements. .
　また、本開示の測距装置は、複数の発光素子と、上記複数の発光素子毎に直列に接続されて発光期間に発光電流を流す複数のスイッチ素子と、上記複数のスイッチ素子を制御することにより上記複数の発光素子の発光を制御する発光制御部と、上記複数の発光素子毎に配置されて発光素子に流れる電流を上記発光電流に制限する複数の電流制限素子と、上記発光電流に応じた電流制御信号を上記複数の電流制限素子の制御端子に供給する発光電流制御部と、上記複数の発光素子のうちの発光させる発光素子数に応じて上記発光電流を調整する発光電流調整部とを備える光源装置と、上記光源装置から出射された光が対象物に反射された反射光を検出する光検出素子と、上記光の出射から反射光の検出までの時間を測定することにより上記対象物までの距離を測定する測距部とを有する。 Further, the distance measuring device of the present disclosure includes a plurality of light emitting elements, a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emitting current to flow during a light emission period, and controlling the plurality of switch elements. a light emission control section that controls light emission of the plurality of light emitting elements, a plurality of current limiting elements that are arranged for each of the plurality of light emitting elements and limit the current flowing through the light emitting elements to the light emitting current; a light emission current control section that supplies a current control signal to the control terminals of the plurality of current limiting elements; and a light emission current adjustment section that adjusts the light emission current according to the number of light emitting elements to emit light among the plurality of light emitting elements. a light source device comprising: a light detection element that detects reflected light from the light emitted from the light source device and reflected by the target object; and a distance measuring section that measures the distance to an object.
本開示の第１の実施形態に係る光源装置の構成例を示す図である。FIG. 1 is a diagram illustrating a configuration example of a light source device according to a first embodiment of the present disclosure. 本開示の実施形態に係る発光電流の変動を説明する図である。FIG. 3 is a diagram illustrating fluctuations in light emitting current according to an embodiment of the present disclosure. 本開示の第１の実施形態に係る発光電流調整部の構成例を示す図である。FIG. 3 is a diagram illustrating a configuration example of a light emitting current adjustment section according to a first embodiment of the present disclosure. 本開示の第１の実施形態に係る調整電流の一例を示す図である。FIG. 3 is a diagram illustrating an example of an adjustment current according to the first embodiment of the present disclosure. 本開示の第２の実施形態に係る光源装置の構成例を示す図である。FIG. 7 is a diagram illustrating a configuration example of a light source device according to a second embodiment of the present disclosure. 本開示の第２の実施形態に係る調整電流の一例を示す図である。FIG. 7 is a diagram illustrating an example of an adjustment current according to a second embodiment of the present disclosure. 本開示の第２の実施形態に係る調整電流の他の例を示す図である。FIG. 7 is a diagram showing another example of the adjustment current according to the second embodiment of the present disclosure. 本開示の第２の実施形態に係る領域の一例を示す図である。FIG. 7 is a diagram illustrating an example of a region according to a second embodiment of the present disclosure. 本開示の第２の実施形態に係る領域の一例を示す図である。FIG. 7 is a diagram illustrating an example of a region according to a second embodiment of the present disclosure. 本開示の第２の実施形態に係る領域の一例を示す図である。FIG. 7 is a diagram illustrating an example of a region according to a second embodiment of the present disclosure. 本開示の第３の実施形態に係る光源装置の構成例を示す図である。FIG. 7 is a diagram illustrating a configuration example of a light source device according to a third embodiment of the present disclosure. 本開示の第３の実施形態に係る調整電流の一例を示す図である。FIG. 7 is a diagram illustrating an example of an adjustment current according to a third embodiment of the present disclosure. 本開示の第４の実施形態に係る光源装置の構成例を示す図である。FIG. 7 is a diagram illustrating a configuration example of a light source device according to a fourth embodiment of the present disclosure. 本開示の第４の実施形態に係る発光電流調整部の構成例を示す図である。FIG. 7 is a diagram illustrating a configuration example of a light emitting current adjustment section according to a fourth embodiment of the present disclosure. 本開示の第４の実施形態に係る発光制御部の構成例を示す図である。FIG. 7 is a diagram illustrating a configuration example of a light emission control section according to a fourth embodiment of the present disclosure. 本開示の第４の実施形態に係る発光信号生成回路の構成例を示す図である。FIG. 7 is a diagram illustrating a configuration example of a light emission signal generation circuit according to a fourth embodiment of the present disclosure. 本開示の第４の実施形態に係る発光信号の生成の一例を示す図である。FIG. 7 is a diagram illustrating an example of generation of a light emission signal according to a fourth embodiment of the present disclosure. 本開示の第５の実施形態に係る光源装置の構成例を示す図である。FIG. 7 is a diagram illustrating a configuration example of a light source device according to a fifth embodiment of the present disclosure. 本開示の実施形態の第１の変形例に係る光源装置の構成例を示す図である。It is a figure showing the example of composition of the light source device concerning the 1st modification of the embodiment of this indication. 本開示の実施形態の第２の変形例に係る光源装置の構成例を示す図である。It is a figure showing the example of composition of the light source device concerning the 2nd modification of the embodiment of this indication. 本開示の実施形態に係る発光素子の構成例を示す図である。1 is a diagram illustrating a configuration example of a light emitting element according to an embodiment of the present disclosure. 本開示の実施形態に係る発光素子の他の構成例を示す図である。FIG. 3 is a diagram illustrating another configuration example of a light emitting element according to an embodiment of the present disclosure. 本開示の実施形態に係る発光素子の発光の一例を示す図である。FIG. 2 is a diagram illustrating an example of light emission from a light emitting element according to an embodiment of the present disclosure. 本開示の実施形態に係る発光素子の発光の一例を示す図である。FIG. 2 is a diagram illustrating an example of light emission from a light emitting element according to an embodiment of the present disclosure. 本開示の実施形態に係る光源装置を適用可能な測距装置の構成例を示す図である。1 is a diagram illustrating a configuration example of a distance measuring device to which a light source device according to an embodiment of the present disclosure can be applied.
　以下に、本開示の実施形態について図面に基づいて詳細に説明する。説明は、以下の順に行う。なお、以下の各実施形態において、同一の部位には同一の符号を付することにより重複する説明を省略する。
１．第１の実施形態
２．第２の実施形態
３．第３の実施形態
４．第４の実施形態
５．第５の実施形態
６．変形例
７．発光素子の構成
８．測距装置への適用例 Embodiments of the present disclosure will be described in detail below based on the drawings. The explanation will be given in the following order. In addition, in each of the following embodiments, the same portions are given the same reference numerals and redundant explanations will be omitted.
1. First embodiment 2. Second embodiment 3. Third embodiment 4. Fourth embodiment 5. Fifth embodiment 6. Modification example 7. Configuration of light emitting element 8. Example of application to distance measuring equipment
　（１．第１の実施形態）
　［光源装置の構成］
　図１は、本開示の第１の実施形態に係る光源装置の構成例を示す図である。同図は、光源装置１０の構成例を表すブロック図である。光源装置１０は、複数（ｎ個）の発光素子１０１乃至１０３と、複数（ｎ個）のスイッチ素子１２１乃至１２３と、複数（ｎ個）の電流制限素子１１１乃至１１３と、ＭＯＳトランジスタ１２４と、発光制御部２０とを備える。また、光源装置１０は、発光電流調整部３０と、発光電流制御部４０と、制御部５０とを更に備える。 (1. First embodiment)
[Configuration of light source device]
FIG. 1 is a diagram illustrating a configuration example of a light source device according to a first embodiment of the present disclosure. This figure is a block diagram showing an example of the configuration of the light source device 10. As shown in FIG. The light source device 10 includes a plurality (n) of light emitting elements 101 to 103, a plurality (n) of switch elements 121 to 123, a plurality (n) of current limiting elements 111 to 113, and a MOS transistor 124. A light emission control section 20 is provided. The light source device 10 further includes a light emission current adjustment section 30, a light emission current control section 40, and a control section 50.
　発光素子１０１乃至１０３は、発光電流を流すことにより発光する半導体の素子である。発光素子１０１等には、例えばレーザダイオードを使用することができる。 The light emitting elements 101 to 103 are semiconductor elements that emit light by flowing a light emitting current. For example, a laser diode can be used as the light emitting element 101 and the like.
　スイッチ素子１２１乃至１２３は、複数の発光素子１０１乃至１０３毎に直列に接続されて発光期間に発光電流を流す素子である。このスイッチ素子１２１乃至１２３には、ｎチャネルＭＯＳトランジスタを使用することができる。 The switch elements 121 to 123 are elements that are connected in series to each of the plurality of light emitting elements 101 to 103 and allow a light emitting current to flow during the light emitting period. N-channel MOS transistors can be used for the switch elements 121 to 123.
　電流制限素子１１１乃至１１３は、複数の発光素子１０１乃至１０３毎に配置されて発光素子１０１乃至１０３に流れる電流を発光電流に制限する素子である。電流制限素子１１１乃至１１３には、ｎチャネルＭＯＳトランジスタを使用することができる。 The current limiting elements 111 to 113 are elements arranged for each of the plurality of light emitting elements 101 to 103 to limit the current flowing through the light emitting elements 101 to 103 to the light emitting current. N-channel MOS transistors can be used for current limiting elements 111 to 113.
　発光電流制御部４０は、発光電流に応じた電流制御信号を複数の電流制限素子１１１乃至１１３の制御端子に供給するものである。なお、電流制限素子１１１乃至１１３のゲートが制御端子に該当する。この発光電流制御部４０は、定電流回路１３０及びＭＯＳトランジスタ１１４を備える。 The light emitting current control section 40 supplies a current control signal according to the light emitting current to the control terminals of the plurality of current limiting elements 111 to 113. Note that the gates of the current limiting elements 111 to 113 correspond to control terminals. This light emitting current control section 40 includes a constant current circuit 130 and a MOS transistor 114.
　光源装置１０の回路の結線について説明する。発光素子１０１のアノードは電源を供給する電源線Ｖｄｄに接続され、発光素子１０１のカソードは電流制限素子１１１のドレインに接続される。電流制限素子１１１のソースはスイッチ素子１２１のドレインに接続され、スイッチ素子１２１のソースは接地される。このように、直列に接続される発光素子１０１、電流制限素子１１１及びスイッチ素子１２１は、電源線Ｖｄｄ及び接地線の間に接続される。発光素子１０２、電流制限素子１１２及びスイッチ素子１２２並びに発光素子１０３、電流制限素子１１３及びスイッチ素子１２３においても同様の結線となる。このような直列に接続された発光素子１０１、電流制限素子１１１及びスイッチ素子１２１のノードを以下発光素子ノードと称する。この発光素子ノードが光源装置１０にｎ個配置される。なお、スイッチ素子１２１乃至１２３のゲートは、それぞれ発光電流制御部４０の出力に接続される。 The circuit connections of the light source device 10 will be explained. The anode of the light emitting element 101 is connected to a power line Vdd that supplies power, and the cathode of the light emitting element 101 is connected to the drain of the current limiting element 111. The source of current limiting element 111 is connected to the drain of switch element 121, and the source of switch element 121 is grounded. In this way, the light emitting element 101, the current limiting element 111, and the switching element 121 connected in series are connected between the power supply line Vdd and the ground line. Similar connections are made in the light emitting element 102, current limiting element 112, and switch element 122, as well as in the light emitting element 103, current limiting element 113, and switch element 123. A node of the light emitting element 101, current limiting element 111, and switch element 121 connected in series is hereinafter referred to as a light emitting element node. n light emitting element nodes are arranged in the light source device 10. Note that the gates of the switch elements 121 to 123 are connected to the output of the light emission current control section 40, respectively.
　発光電流制御部４０の定電流回路１３０のシンク側端子は電源線Ｖｄｄに接続され、ソース側端子はＭＯＳトランジスタ１１４のドレイン及びゲート並びに電流制限素子１１１乃至１１３のゲートに接続される。ＭＯＳトランジスタ１１４のソースはＭＯＳトランジスタ１２４のドレインに接続され、ＭＯＳトランジスタ１２４のソースは接地される。ＭＯＳトランジスタ１２４のゲートは電源線Ｖｄｄに接続される。 The sink side terminal of the constant current circuit 130 of the light emitting current control section 40 is connected to the power supply line Vdd, and the source side terminal is connected to the drain and gate of the MOS transistor 114 and the gates of the current limiting elements 111 to 113. The source of MOS transistor 114 is connected to the drain of MOS transistor 124, and the source of MOS transistor 124 is grounded. The gate of MOS transistor 124 is connected to power supply line Vdd.
　同図に表したように、発光電流制御部４０のＭＯＳトランジスタ１１４と電流制限素子１１１乃至１１３とはカレントミラー回路を構成する。すなわち、ＭＯＳトランジスタ１１４に流れる電流である参照電流が電流制限素子１１１乃至１１３にミラーされる。なお、ＭＯＳトランジスタ１２４は、スイッチ素子１２１に相当する電圧降下を得るために接続される素子である。このため、カレントミラー回路のミラー比は１：１となる。例えば、スイッチ素子１２１乃至１２３を導通させることにより電流制限素子１１１乃至１１３のソース及び接地線の間が略短絡状態になる。このため、定電流回路１３０の参照電流に等しい電流が電流制限素子１１１乃至１１３にそれぞれ流れる。この電流が発光電流となる。 As shown in the figure, the MOS transistor 114 of the light emitting current control section 40 and the current limiting elements 111 to 113 constitute a current mirror circuit. That is, the reference current, which is the current flowing through the MOS transistor 114, is mirrored by the current limiting elements 111 to 113. Note that the MOS transistor 124 is an element connected to obtain a voltage drop equivalent to that of the switch element 121. Therefore, the mirror ratio of the current mirror circuit is 1:1. For example, by making the switch elements 121 to 123 conductive, the sources of the current limiting elements 111 to 113 and the ground line are approximately short-circuited. Therefore, currents equal to the reference current of constant current circuit 130 flow through current limiting elements 111 to 113, respectively. This current becomes a light emitting current.
　スイッチ素子１２１乃至１２３を選択して導通させることにより、所望の発光素子を発光させることができる。なお、定電流回路１３０の参照電流は、後述する発光電流調整部３０により制御される。 By selecting the switch elements 121 to 123 and making them conductive, a desired light emitting element can be caused to emit light. Note that the reference current of the constant current circuit 130 is controlled by a light emitting current adjustment section 30, which will be described later.
　なお、同図の光源装置１０は、発光素子１０１乃至１０３及び発光電流制御部４０が同一の電源（電源線Ｖｄｄ）に接続される例を表したものであるが、発光素子１０１等の回路構成は、この例に限定されない。例えば、発光素子１０１乃至１０３と発光電流制御部４０とに異なる電源（回路）を接続することもできる。この際、発光素子１０１乃至１０３と発光電流制御部４０とにおいて異なる電圧の電源を供給することもできる。また、発光電流制御部４０のＭＯＳトランジスタ１１４と電流制限素子１１１乃至１１３とにより構成されるカレントミラー回路のミラー比を異なる値にすることもできる。例えば、ＭＯＳトランジスタ１１４に対する電流制限素子１１１乃至１１３のアスペクト比をＮ倍にすることにより、ミラー比を１：Ｎにすることができる。これにより、発光電流制御部４０等の消費電力を低減することができる。なお、この場合には、ＭＯＳトランジスタ１２４に対するスイッチ素子１２１乃至１２３のアスペクト比もＮ倍にする必要がある。 Note that the light source device 10 in the figure represents an example in which the light emitting elements 101 to 103 and the light emitting current control unit 40 are connected to the same power source (power line Vdd), but the circuit configuration of the light emitting element 101 etc. is not limited to this example. For example, different power supplies (circuits) may be connected to the light emitting elements 101 to 103 and the light emitting current control section 40. At this time, power supplies with different voltages can be supplied to the light emitting elements 101 to 103 and the light emitting current control unit 40. Further, the mirror ratio of the current mirror circuit constituted by the MOS transistor 114 of the light emission current control section 40 and the current limiting elements 111 to 113 can be set to different values. For example, by increasing the aspect ratio of current limiting elements 111 to 113 to MOS transistor 114 by N times, the mirror ratio can be set to 1:N. Thereby, power consumption of the light emitting current control section 40 and the like can be reduced. Note that in this case, the aspect ratio of the switch elements 121 to 123 with respect to the MOS transistor 124 must also be increased by N times.
　発光制御部２０は、複数のスイッチ素子１２１乃至１２３を制御することにより複数の発光素子１０１乃至１０３の発光を制御するものである。この発光制御部２０は、スイッチ素子１２１乃至１２３を個別に導通させて制御する。発光制御部２０は、スイッチ素子１２１乃至１２３を構成するＭＯＳトランジスタのオン信号を出力する。このオン信号は、ＭＯＳトランジスタを導通状態にするゲートソース間電圧Ｖｇｓ以上の電圧の信号である。このオン信号がゲートに印加されたスイッチ素子１２１等が導通状態になる。 The light emission control unit 20 controls the light emission of the plurality of light emitting elements 101 to 103 by controlling the plurality of switch elements 121 to 123. This light emission control section 20 controls the switching elements 121 to 123 by individually turning them on. The light emission control section 20 outputs ON signals for the MOS transistors forming the switch elements 121 to 123. This on signal is a signal with a voltage higher than the gate-source voltage Vgs that turns the MOS transistor into a conductive state. The switch element 121 and the like to which this ON signal is applied to the gate become conductive.
　発光制御部２０には、駆動信号及び発光パタンが入力される。駆動信号は、発光素子１０１乃至１０３を発光させるタイミングを示す信号であり、スイッチ素子１２１乃至１２３を導通状態にするタイミングを示す信号である。また、発光パタンは、発光素子１０１乃至１０３のうち発光させる発光素子を示す信号である。発光制御部２０は、発光パタンに基づいてスイッチ素子１２１乃至１２３を選択し、駆動信号に基づくタイミングにおいて選択したスイッチ素子１２１乃至１２３にオン信号を出力する。 A drive signal and a light emission pattern are input to the light emission control section 20. The drive signal is a signal indicating the timing to cause the light emitting elements 101 to 103 to emit light, and is a signal indicating the timing to make the switch elements 121 to 123 conductive. Further, the light emission pattern is a signal indicating which light emitting element to emit light among the light emitting elements 101 to 103. The light emission control unit 20 selects the switch elements 121 to 123 based on the light emission pattern, and outputs an ON signal to the selected switch elements 121 to 123 at a timing based on the drive signal.
　発光電流調整部３０は、発光電流制御部４０の発光電流を制御する。具体的には、発光電流調整部３０は、発光電流制御部４０の定電流回路１３０に発光電流に相当する参照電流を流す制御を行う。また、発光電流調整部３０は、複数の発光素子１０１乃至１０３のうちの発光させる発光素子数に応じた発光電流の調整を更に行う。後述するように、カレントミラー回路を構成する電流制限素子１１１乃至１１３は、発光素子数に応じて発光電流が変化する。発光電流調整部３０は、この発光電流の変化を補償するため、発光電流を調整する。発光電流調整部３０の構成の詳細については後述する。 The light emission current adjustment section 30 controls the light emission current of the light emission current control section 40. Specifically, the light emitting current adjustment section 30 controls the constant current circuit 130 of the light emitting current control section 40 to flow a reference current corresponding to the light emitting current. Further, the light emitting current adjustment unit 30 further adjusts the light emitting current according to the number of light emitting elements to emit light among the plurality of light emitting elements 101 to 103. As will be described later, the light emitting current of the current limiting elements 111 to 113 that constitute the current mirror circuit changes depending on the number of light emitting elements. The light emitting current adjustment section 30 adjusts the light emitting current in order to compensate for this change in the light emitting current. Details of the configuration of the light emitting current adjustment section 30 will be described later.
　制御部５０は、光源装置１０の全体を制御するものである。この制御部５０は、外部の装置からの指示に基づいて電流制御信号、発光パタン及び駆動信号を生成し、発光電流調整部３０及び発光制御部２０に対して出力する。 The control unit 50 controls the entire light source device 10. The control section 50 generates a current control signal, a light emission pattern, and a drive signal based on instructions from an external device, and outputs them to the light emission current adjustment section 30 and the light emission control section 20.
　［発光電流の変動］
　図２は、本開示の実施形態に係る発光電流の変動を説明する図である。同図は、図１の発光素子１０１乃至１０３の回路部分を記載した図である。同図において、Ｉ０はＭＯＳトランジスタ１１４の電流（参照電流）を表す。また、Ｉ１乃至Ｉｎは、電流制限素子１１１乃至１１３の発光電流を表す。また、同図にはカレントミラー回路を構成するＭＯＳトランジスタ１１４並びに電流制限素子１１１乃至１１３のソース側配線の寄生抵抗を記載した。同図の破線の抵抗器が寄生抵抗に該当する。通常、配線には配線抵抗に基づく寄生抵抗が存在する。このため、配線に電流を流すと電圧降下を生じる。これらの寄生抵抗がＭＯＳトランジスタ１１４と電流制限素子１１１乃至１１３とにおいて異なる場合、ＭＯＳトランジスタ１１４等のソース電圧が変化し、ミラー比が変化して発光電流Ｉ１乃至Ｉｎにばらつきを生じる。 [Fluctuation of light emitting current]
FIG. 2 is a diagram illustrating fluctuations in light emitting current according to the embodiment of the present disclosure. This figure is a diagram illustrating the circuit portions of the light emitting elements 101 to 103 in FIG. 1. In the figure, I0 represents the current (reference current) of the MOS transistor 114. Further, I 1 to I n represent the light emission currents of the current limiting elements 111 to 113. The figure also shows the parasitic resistances of the source-side wiring of the MOS transistor 114 and the current limiting elements 111 to 113 that constitute the current mirror circuit. The resistor indicated by the broken line in the figure corresponds to the parasitic resistance. Usually, wiring has parasitic resistance based on wiring resistance. Therefore, when current flows through the wiring, a voltage drop occurs. If these parasitic resistances are different between the MOS transistor 114 and the current limiting elements 111 to 113, the source voltage of the MOS transistor 114 etc. changes, the mirror ratio changes, and the light emitting currents I 1 to I n vary.
　電流制限素子１１１を例に挙げて説明すると、電流制限素子１１１のソース側配線には、寄生抵抗３０１及び３０２が存在する。この寄生抵抗３０１及び３０２がＭＯＳトランジスタ１１４の寄生抵抗と異なる場合、電流制限素子１１１及びＭＯＳトランジスタ１１４の実効的なゲートソース間電圧Ｖｇｓが異なるため、電流制限素子１１１の発光電流Ｉ１は電流制限素子１１１の電流Ｉ０とは異なる値になる。 Taking the current limiting element 111 as an example, parasitic resistances 301 and 302 are present in the source side wiring of the current limiting element 111. When the parasitic resistances 301 and 302 are different from the parasitic resistance of the MOS transistor 114, the effective gate-source voltages Vgs of the current limiting element 111 and the MOS transistor 114 are different, so that the light emitting current I1 of the current limiting element 111 is limited by the current limit. The current I of the element 111 has a value different from 0 .
　また、接地線にも寄生抵抗が存在する。この寄生抵抗のうち、複数の発光電流が共通に流れる寄生抵抗は共通インピーダンスと称される。同図の寄生抵抗３０３は、発光電流Ｉ１乃至Ｉｎが流れる共通インピーダンスに該当する。この共通インピーダンスとなる寄生抵抗３０３の電圧降下は、流れる発光電流により変化する。すなわち、寄生抵抗３０３の電圧降下は、発光素子１０１乃至１０３の発光素子数により変化する。このため、寄生抵抗３０３に発光電流Ｉ１が流れる電流制限素子１１１は、他の発光素子ノードから発光電流により、実効的なゲートソース間電圧Ｖｇｓが変化し、発光電流が変動する。 There is also parasitic resistance in the grounding wire. Among these parasitic resistances, a parasitic resistance through which a plurality of light emitting currents commonly flow is called a common impedance. The parasitic resistance 303 in the figure corresponds to a common impedance through which the light emitting currents I 1 to I n flow. The voltage drop across the parasitic resistor 303, which serves as this common impedance, changes depending on the flowing light emitting current. That is, the voltage drop across the parasitic resistance 303 changes depending on the number of light emitting elements 101 to 103. Therefore, in the current limiting element 111 where the light emitting current I1 flows through the parasitic resistance 303, the effective gate-source voltage Vgs changes due to the light emitting current from other light emitting element nodes, and the light emitting current fluctuates.
　具体的には、発光素子１０１のみを発光させる際には、寄生抵抗３０３に発光電流Ｉ１のみが流れるため、寄生抵抗３０３の電圧降下がＭＯＳトランジスタ１１４における接地線の寄生抵抗３０４の電圧降下と略等しくなる。このため、発光素子１０１の発光電流Ｉ１はＩ０と略等しい電流となる。これに対し、発光素子１０１乃至１０３の全てが発光する場合、寄生抵抗３０３の電圧降下が増加して実効的なゲートソース間電圧Ｖｇｓが低下するため発光電流Ｉ１がＩ０より低下する。このように、発光素子１０１乃至１０３のうちの発光素子数に応じて発光電流が変化する。発光電流調整部３０は、この発光電流の変化を補償する動作を行う。 Specifically, when only the light emitting element 101 emits light, only the light emitting current I1 flows through the parasitic resistor 303, so the voltage drop across the parasitic resistor 303 is equal to the voltage drop across the parasitic resistor 304 of the ground line in the MOS transistor 114. They are almost equal. Therefore, the light emitting current I 1 of the light emitting element 101 is approximately equal to I 0 . On the other hand, when all of the light emitting elements 101 to 103 emit light, the voltage drop across the parasitic resistance 303 increases and the effective gate-source voltage Vgs decreases, so that the light emitting current I 1 is lower than I 0 . In this way, the light emitting current changes depending on the number of light emitting elements among the light emitting elements 101 to 103. The light emitting current adjustment section 30 performs an operation to compensate for this change in light emitting current.
　［発光電流調整部の構成］
　図３は、本開示の第１の実施形態に係る発光電流調整部の構成例を示す図である。同図は、発光電流調整部３０の構成例を表すブロック図である。同図の発光電流調整部３０は、発光素子数検出部３１と、駆動調整部３２と、調整電流保持部３３とを備える。 [Configuration of light emitting current adjustment section]
FIG. 3 is a diagram illustrating a configuration example of a light emission current adjustment section according to the first embodiment of the present disclosure. This figure is a block diagram showing an example of the configuration of the light emitting current adjustment section 30. As shown in FIG. The light emitting current adjusting section 30 in the figure includes a light emitting element number detecting section 31, a drive adjusting section 32, and an adjusted current holding section 33.
　発光素子数検出部３１は、発光パタンに基づいて発光素子数を検出するものである。この発光素子数検出部３１は、発光素子数を駆動調整部３２に出力する。 The light emitting element number detection unit 31 detects the number of light emitting elements based on a light emission pattern. The light emitting element number detection section 31 outputs the number of light emitting elements to the drive adjustment section 32.
　駆動調整部３２は、電流制御信号に基づいて、発光電流調整部３０の定電流回路１３０に参照電流を流す制御を行う。また、駆動調整部３２は、発光素子数検出部３１からの発光素子数に基づいて定電流回路１３０の参照電流を調整する制御を更に行う。駆動調整部３２は、調整電流保持部３３の調整電流に基づいて参照電流の調整を行う。 The drive adjustment section 32 controls the flow of a reference current through the constant current circuit 130 of the light emitting current adjustment section 30 based on the current control signal. Further, the drive adjustment section 32 further performs control to adjust the reference current of the constant current circuit 130 based on the number of light emitting elements from the light emitting element number detection section 31. The drive adjustment section 32 adjusts the reference current based on the adjustment current of the adjustment current holding section 33.
　調整電流保持部３３は、参照電流を調整するための調整電流の情報を保持するものである。調整電流保持部３３は、発光素子数及び調整電流の対応を表すテーブルを備える。 The adjustment current holding unit 33 holds information on the adjustment current for adjusting the reference current. The adjustment current holding unit 33 includes a table showing the correspondence between the number of light emitting elements and the adjustment current.
　［調整電流］
　図４は、本開示の第１の実施形態に係る調整電流の一例を示す図である。同図は、調整電流保持部３３に保持される調整電流の一例を表す図である。同図の発光素子数は、発光素子１０１乃至１０３のうちの発光素子数を表す。同図は、発光素子（発光素子ノード）が１０個の場合を表したものである。同図の調整電流は、発光電流の調整値を表す。同図の調整電流は、発光素子数が１０の場合を基準とし、発光素子数の減少に伴い値が増加する例を表したものである。具体的には、発光素子数が「１」の場合には、調整電流が「－５％」となる。この場合、駆動調整部３２は、発光素子数が「１０」の場合の発光電流（参照電流）に対して５％減じる調整を行う。駆動調整部３２は、この調整後の参照電流を流すように定電流回路１３０を制御する。これにより、発光素子数に応じて発光電流の値が調整される。 [Adjustment current]
FIG. 4 is a diagram illustrating an example of the adjustment current according to the first embodiment of the present disclosure. This figure is a diagram showing an example of the adjustment current held in the adjustment current holding section 33. The number of light emitting elements in the figure represents the number of light emitting elements among the light emitting elements 101 to 103. This figure shows a case where there are 10 light emitting elements (light emitting element nodes). The adjusted current in the figure represents the adjusted value of the light emitting current. The adjustment current in the figure is based on the case where the number of light emitting elements is 10, and represents an example in which the value increases as the number of light emitting elements decreases. Specifically, when the number of light emitting elements is "1", the adjustment current is "-5%". In this case, the drive adjustment unit 32 performs an adjustment to reduce the light emitting current (reference current) by 5% when the number of light emitting elements is "10". The drive adjustment section 32 controls the constant current circuit 130 to flow the adjusted reference current. Thereby, the value of the light emitting current is adjusted according to the number of light emitting elements.
　このように、本開示の第１の実施形態の光源装置１０は、発光素子数に応じて発光素子１０１乃至１０３の発光電流を調整する。これにより、発光素子１０１乃至１０３の発光電流の変動を低減することができ、光源装置１０の光量の変動を低減することができる。 In this way, the light source device 10 of the first embodiment of the present disclosure adjusts the light emitting current of the light emitting elements 101 to 103 according to the number of light emitting elements. Thereby, fluctuations in the light emitting currents of the light emitting elements 101 to 103 can be reduced, and fluctuations in the amount of light from the light source device 10 can be reduced.
　（２．第２の実施形態）
　上述の第１の実施形態の光源装置１０は、複数の発光素子が配置されていた。これに対し、本開示の第２の実施形態の光源装置１０は、複数の発光素子が複数の領域に分割される点で、上述の第１の実施形態と異なる。 (2. Second embodiment)
In the light source device 10 of the first embodiment described above, a plurality of light emitting elements are arranged. On the other hand, the light source device 10 according to the second embodiment of the present disclosure differs from the above-described first embodiment in that a plurality of light emitting elements are divided into a plurality of regions.
　［光源装置の構成］
　図５は、本開示の第２の実施形態に係る光源装置の構成例を示す図である。同図は、図１と同様に、光源装置１０の構成例を表す図である。同図の光源装置１０は、発光素子ノードが複数の領域に分割される点で、図１の光源装置１０と異なる。 [Configuration of light source device]
FIG. 5 is a diagram illustrating a configuration example of a light source device according to a second embodiment of the present disclosure. This figure, like FIG. 1, is a diagram showing a configuration example of the light source device 10. The light source device 10 in the figure differs from the light source device 10 in FIG. 1 in that the light emitting element node is divided into a plurality of regions.
　同図の光源装置１０は、発光素子１０１乃至１０３の発光素子ノードからなる領域１００と発光素子１５１乃至１５３の発光素子ノードからなる領域１５０を備える。領域１５０は、発光素子１５１乃至１５３、電流制限素子１６１乃至１６３及びスイッチ素子１７１乃至１７３を備える。これらの発光素子１５１乃至１５３がそれぞれ発光素子ノードを構成する。なお、同図の領域１５０は、領域１００と同数の発光素子ノードを備える例を表したものである。また、領域１５０の電流制限素子１６１乃至１６３は、ＭＯＳトランジスタ１１４とカレントミラー回路を構成する。このような領域１００及び１５０を備える構成は、複数の発光素子１０１等がハードウェア的に分割される場合に適用されるものである。 The light source device 10 in the figure includes a region 100 consisting of light emitting element nodes of light emitting elements 101 to 103 and a region 150 consisting of light emitting element nodes of light emitting elements 151 to 153. The region 150 includes light emitting elements 151 to 153, current limiting elements 161 to 163, and switching elements 171 to 173. These light emitting elements 151 to 153 each constitute a light emitting element node. Note that the region 150 in the figure represents an example including the same number of light emitting element nodes as the region 100. Further, current limiting elements 161 to 163 in region 150 constitute a current mirror circuit with MOS transistor 114. A configuration including such areas 100 and 150 is applied when a plurality of light emitting elements 101 and the like are divided by hardware.
　［調整電流］
　図６は、本開示の第２の実施形態に係る調整電流の一例を示す図である。同図は、図４と同様に、調整電流保持部３３に保持される調整電流の一例を表す図である。同図の「領域♯１」及び「領域♯２」は、それぞれ領域１００及び１５０の発光素子数を表す。領域１００及び１５０において発光素子数が「５」のときに最も小さい（絶対値が最も大きい）調整値となる。 [Adjustment current]
FIG. 6 is a diagram illustrating an example of the adjustment current according to the second embodiment of the present disclosure. This figure, like FIG. 4, is a diagram showing an example of the adjustment current held in the adjustment current holding section 33. "Region #1" and "Region #2" in the figure represent the number of light emitting elements in regions 100 and 150, respectively. In regions 100 and 150, when the number of light emitting elements is "5", the adjustment value is the smallest (the absolute value is the largest).
　図７は、本開示の第２の実施形態に係る調整電流の他の例を示す図である。同図は、図６と同様に、調整電流保持部３３に保持される調整電流の一例を表す図である。同図は、発光電流に応じて調整値を変化させる例を表したものである。同図の左端の調整電流は、発光電流が低い場合（低光量の場合）の調整電流を表したものである。また、同図の中央の調整電流は、中位の発光電流の場合の調整電流を表したものである。また、同図の右端の調整電流は、発光電流が大きい場合（高光量の場合）の調整電流を表したものである。同図に表したように、発光電流が大きい場合には、調整値を大きくすることができる。共通インピーダンスである寄生抵抗３０３の電圧降下が増加するためである。 FIG. 7 is a diagram showing another example of the adjustment current according to the second embodiment of the present disclosure. This figure, like FIG. 6, is a diagram showing an example of the adjustment current held in the adjustment current holding section 33. The figure shows an example in which the adjustment value is changed depending on the light emitting current. The adjustment current at the left end of the figure represents the adjustment current when the light emitting current is low (low light amount). Further, the adjustment current in the center of the figure represents the adjustment current in the case of an intermediate light emission current. Further, the adjustment current at the right end of the figure represents the adjustment current when the light emission current is large (when the amount of light is high). As shown in the figure, when the light emitting current is large, the adjustment value can be increased. This is because the voltage drop across the parasitic resistance 303, which is a common impedance, increases.
　［領域の構成］
　図８Ａ－８Ｃは、本開示の第２の実施形態に係る領域の一例を示す図である。同図の矩形は発光素子１０１等を表す。同図において発光素子１０１等は、２次元行列状に配置される。また、同図の白抜きの矩形は、領域１００に含まれる発光素子を表し、斜線ハッチングを付した矩形は、領域１５０に含まれる発光素子を表す。 [Area configuration]
8A-8C are diagrams illustrating examples of regions according to the second embodiment of the present disclosure. The rectangles in the figure represent the light emitting elements 101 and the like. In the figure, light emitting elements 101 and the like are arranged in a two-dimensional matrix. Furthermore, the white rectangles in the figure represent light-emitting elements included in the region 100, and the hatched rectangles represent light-emitting elements contained in the region 150.
　図８Ａは、複数の発光素子１０１等が長方形の形状の領域１００及び１５０に２等分される例を表したものである。 FIG. 8A shows an example in which a plurality of light emitting elements 101 etc. are equally divided into two rectangular regions 100 and 150.
　図８Ｂは、複数の発光素子１０１等のうちの外周の発光素子が領域１５０に配置され、内側の発光素子が領域１００に配置される例を表したものである。 FIG. 8B shows an example in which the outer light emitting elements of the plurality of light emitting elements 101 and the like are arranged in the region 150, and the inner light emitting elements are arranged in the region 100.
　図８Ｃは、複数の発光素子１０１等が列毎に領域１００及び１５０に交互に振り分けられる例を表したものである。 FIG. 8C shows an example in which a plurality of light emitting elements 101 and the like are alternately distributed to regions 100 and 150 for each column.
　これ以外の光源装置１０の構成は本開示の第１の実施形態における光源装置１０の構成と同様であるため、説明を省略する。 The configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
　このように、本開示の第２の実施形態の光源装置１０は、複数の発光素子１０１等が複数の領域１００等に分割される場合において、発光素子数に応じて発光素子１０１乃至１０３等の発光電流を調整する。 As described above, in the light source device 10 of the second embodiment of the present disclosure, when a plurality of light emitting elements 101, etc. are divided into a plurality of regions 100, etc., the light emitting elements 101 to 103, etc. are divided according to the number of light emitting elements. Adjust the emission current.
　（３．第３の実施形態）
　上述の第２の実施形態の光源装置１０は、複数の発光素子１０１等が領域１００及び１５０に分割されていた。これに対し、本開示の第３の実施形態の光源装置１０は、分割された領域毎に電流制限素子１６１等のカレントミラー回路を構成する点で、上述の第２の実施形態と異なる。 (3. Third embodiment)
In the light source device 10 of the second embodiment described above, the plurality of light emitting elements 101 and the like are divided into regions 100 and 150. In contrast, the light source device 10 according to the third embodiment of the present disclosure differs from the above-described second embodiment in that a current mirror circuit such as the current limiting element 161 is configured for each divided region.
　［光源装置の構成］
　図９は、本開示の第３の実施形態に係る光源装置の構成例を示す図である。同図は、図５と同様に、光源装置１０の構成例を表す図である。同図の光源装置１０は、領域１００及び１５０において異なるカレントミラー回路が配置される点で、図５の光源装置１０と異なる。 [Configuration of light source device]
FIG. 9 is a diagram illustrating a configuration example of a light source device according to a third embodiment of the present disclosure. This figure, like FIG. 5, is a diagram showing a configuration example of the light source device 10. The light source device 10 in the figure differs from the light source device 10 in FIG. 5 in that different current mirror circuits are arranged in regions 100 and 150.
　同図の光源装置１０は、定電流回路１３１、ＭＯＳトランジスタ１６４及び１７４を更に備える。なお、定電流回路１３１及びＭＯＳトランジスタ１６４の回路は、発光電流制御部４１を構成する。 The light source device 10 in the figure further includes a constant current circuit 131 and MOS transistors 164 and 174. Note that the constant current circuit 131 and the MOS transistor 164 constitute the light emitting current control section 41.
　発光電流制御部４１の定電流回路１３１のシンク側端子は電源線Ｖｄｄに接続され、ソース側端子はＭＯＳトランジスタ１６４のドレイン及びゲート並びに電流制限素子１６１乃至１６３のゲートに接続される。ＭＯＳトランジスタ１６４のソースはＭＯＳトランジスタ１７４のドレインに接続され、ＭＯＳトランジスタ１７４のソースは接地される。ＭＯＳトランジスタ１７４のゲートは、電源線Ｖｄｄ接続される。 The sink side terminal of the constant current circuit 131 of the light emitting current control section 41 is connected to the power supply line Vdd, and the source side terminal is connected to the drain and gate of the MOS transistor 164 and the gates of the current limiting elements 161 to 163. The source of MOS transistor 164 is connected to the drain of MOS transistor 174, and the source of MOS transistor 174 is grounded. The gate of MOS transistor 174 is connected to power supply line Vdd.
　また、同図の光源装置１０の発光電流調整部３０（不図示）は、複数の発光電流制御部４０及び４１の発光電流の調整を行う。 Further, the light emitting current adjustment section 30 (not shown) of the light source device 10 in the figure adjusts the light emitting current of the plurality of light emitting current control sections 40 and 41.
　［調整電流］
　図１０は、本開示の第３の実施形態に係る調整電流の一例を示す図である。同図は、図６と同様に、調整電流保持部３３に保持される調整電流の一例を表す図である。同図に表したように、本開示の第３の実施形態に係る調整電流保持部３３は、領域１００及び１５０毎に調整電流を保持する。これら領域１００及び１５０毎の調整電流に基づいて、発光電流調整部３０は、領域１００及び１５０毎に発光電流の調整を行うことができる。例えば、図８Ｂの領域１００及び１５０のように、領域毎に共通インピーダンスである寄生抵抗の配置が大きく異なる場合であっても、領域１００及び１５０毎に発光電流を補償することができる。 [Adjustment current]
FIG. 10 is a diagram illustrating an example of the adjustment current according to the third embodiment of the present disclosure. This figure, like FIG. 6, is a diagram showing an example of the adjustment current held in the adjustment current holding section 33. As shown in the figure, the adjusted current holding unit 33 according to the third embodiment of the present disclosure holds the adjusted current for each region 100 and 150. Based on the adjusted currents for each of the regions 100 and 150, the light emitting current adjustment section 30 can adjust the light emitting current for each of the regions 100 and 150. For example, even if the arrangement of the parasitic resistance, which is a common impedance, differs greatly from region to region, as in regions 100 and 150 in FIG. 8B, the light emitting current can be compensated for each region 100 and 150.
　これ以外の光源装置１０の構成は本開示の第２の実施形態における光源装置１０の構成と同様であるため、説明を省略する。 The configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the second embodiment of the present disclosure, so the description will be omitted.
　このように、本開示の第３の実施形態の光源装置１０は、領域１００及び１５０毎に発光電流制御部４０及び４１を備える。これにより、発光電流の変動を更に低減することができる。 As described above, the light source device 10 according to the third embodiment of the present disclosure includes the light emission current control units 40 and 41 for each of the regions 100 and 150. Thereby, fluctuations in the light emitting current can be further reduced.
　（４．第４の実施形態）
　上述の第１の実施形態の光源装置１０は、発光電流値を調整することにより、発光電流の調整を行っていた。これに対し、本開示の第４の実施形態の光源装置１０は、発光電流が流れる期間を調整することにより、発光電流を調整する点で、上述の第１の実施形態と異なる。 (4. Fourth embodiment)
The light source device 10 of the first embodiment described above adjusts the light emitting current by adjusting the light emitting current value. On the other hand, the light source device 10 according to the fourth embodiment of the present disclosure differs from the above-described first embodiment in that the light emitting current is adjusted by adjusting the period in which the light emitting current flows.
　［光源装置の構成］
　図１１は、本開示の第４の実施形態に係る光源装置の構成例を示す図である。同図は、図１と同様に、光源装置１０の構成例を表す図である。同図の光源装置１０は、発光制御部２０が発光電流調整部３０から出力される発光期間調整信号に基づいて発光素子１０１等の発光期間を調整する点で、図１の光源装置１０と異なる。 [Configuration of light source device]
FIG. 11 is a diagram illustrating a configuration example of a light source device according to a fourth embodiment of the present disclosure. This figure, like FIG. 1, is a diagram showing a configuration example of the light source device 10. The light source device 10 shown in FIG. 1 differs from the light source device 10 shown in FIG. .
　同図の発光電流調整部３０は、発光電流制御部４０の発光電流（参照電流）の調整を行う必要がない。その代わり、同図の発光電流調整部３０は、発光期間調整信号を発光制御部２０に対して出力する。この発光期間調整信号は、発光素子数に応じて発光期間を調整する信号である。 The light emitting current adjustment section 30 in the figure does not need to adjust the light emitting current (reference current) of the light emitting current control section 40. Instead, the light emission current adjustment section 30 in the figure outputs a light emission period adjustment signal to the light emission control section 20. This light emission period adjustment signal is a signal that adjusts the light emission period according to the number of light emitting elements.
　同図の発光制御部２０は、発光期間調整信号に基づいて発光期間が調整されたバルス状のオン信号をスイッチ素子１２１乃至１２３に出力する。 The light emission control section 20 in the figure outputs a pulse-like ON signal whose light emission period is adjusted based on the light emission period adjustment signal to the switch elements 121 to 123.
　［発光電流調整部の構成］
　図１２は、本開示の第４の実施形態に係る発光電流調整部の構成例を示す図である。同図は、図３と同様に、発光電流調整部３０の構成例を表すブロック図である。同図の発光電流調整部３０は、参照電流制御部３４を更に備え、駆動調整部３２が発光期間調整信号を生成して出力する点で、図３の発光電流調整部３０と異なる。 [Configuration of light emitting current adjustment section]
FIG. 12 is a diagram illustrating a configuration example of a light emission current adjustment section according to a fourth embodiment of the present disclosure. Similar to FIG. 3, this figure is a block diagram showing a configuration example of the light emitting current adjustment section 30. The light emitting current adjusting section 30 shown in the figure is different from the light emitting current adjusting section 30 shown in FIG. 3 in that it further includes a reference current controlling section 34, and the drive adjusting section 32 generates and outputs a light emitting period adjustment signal.
　参照電流制御部３４は、電流制御信号に基づいて発光電流制御部４０の定電流回路１３０に参照電流を流す制御を行うものである。 The reference current control unit 34 controls the flow of a reference current to the constant current circuit 130 of the light emitting current control unit 40 based on the current control signal.
　同図の駆動調整部３２は、発光素子数検出部３１からの発光素子数に基づいて発光期間調整信号を生成する。この発光期間調整信号は、後述する発光制御部２０の発光信号生成回路２２の遅延回路２２１に入力される。発光期間調整信号は、遅延回路２２１の遅延時間を指示する信号である。 The drive adjustment section 32 in the figure generates a light emission period adjustment signal based on the number of light emitting elements from the light emitting element number detection section 31. This light emission period adjustment signal is input to a delay circuit 221 of a light emission signal generation circuit 22 of a light emission control section 20, which will be described later. The light emission period adjustment signal is a signal that indicates the delay time of the delay circuit 221.
　［発光制御部の構成］
　図１３は、本開示の第４の実施形態に係る発光制御部の構成例を示す図である。同図は、発光制御部２０の構成例を表すブロック図である。同図の発光制御部２０は、非反転バッファ２１と、発光信号生成回路２２と、発光素子選択部２３と、複数のゲート駆動回路２４とを備える。 [Configuration of light emission control section]
FIG. 13 is a diagram illustrating a configuration example of a light emission control section according to a fourth embodiment of the present disclosure. This figure is a block diagram showing a configuration example of the light emission control section 20. As shown in FIG. The light emission control section 20 in the figure includes a non-inverting buffer 21, a light emission signal generation circuit 22, a light emitting element selection section 23, and a plurality of gate drive circuits 24.
　非反転バッファ２１は、緩衝増幅器に相当し、駆動信号を増幅して発光信号生成回路２２に出力するものである。 The non-inverting buffer 21 corresponds to a buffer amplifier and amplifies the drive signal and outputs it to the light emission signal generation circuit 22.
　発光信号生成回路２２は、非反転バッファ２１を介して入力される駆動信号に基づいてパルス状の発光信号を生成する回路である。また、発光信号生成回路２２は、発光電流調整部３０からの発光期間調整信号に基づいて発光信号のハルス幅の調整を更に行う。発光信号生成回路２２の構成の詳細については後述する。 The light emission signal generation circuit 22 is a circuit that generates a pulsed light emission signal based on a drive signal inputted via the non-inverting buffer 21. Furthermore, the light emission signal generation circuit 22 further adjusts the Hals width of the light emission signal based on the light emission period adjustment signal from the light emission current adjustment section 30. Details of the configuration of the light emission signal generation circuit 22 will be described later.
　発光素子選択部２３は、発光パタンに基づいて発光させる発光素子１０１等を選択し、選択した発光素子１０１等の発光素子ノードに発光信号を出力するものである。 The light emitting element selection unit 23 selects the light emitting element 101 etc. to emit light based on the light emitting pattern, and outputs a light emitting signal to the light emitting element node of the selected light emitting element 101 etc.
　ゲート駆動回路２４は、発光素子ノード毎に配置され、発光素子選択部２３からの発光信号に基づいてパルス状のオン信号を生成し、出力するものである。 The gate drive circuit 24 is arranged for each light emitting element node, and generates and outputs a pulsed ON signal based on the light emission signal from the light emitting element selection section 23.
　［発光信号生成回路の構成］
　図１４Ａは、本開示の第４の実施形態に係る発光信号生成回路の構成例を示す図である。同図は、発光信号生成回路２２の構成例を表すブロック図である。同図の発光信号生成回路２２は、遅延回路２２１と、ＡＮＤゲート２２２とを備える。 [Configuration of light emission signal generation circuit]
FIG. 14A is a diagram illustrating a configuration example of a light emission signal generation circuit according to a fourth embodiment of the present disclosure. This figure is a block diagram showing a configuration example of the light emission signal generation circuit 22. As shown in FIG. The light emission signal generation circuit 22 in the figure includes a delay circuit 221 and an AND gate 222.
　遅延回路２２１は、発光期間調整信号に基づいて駆動信号を遅延させる回路である。ＡＮＤゲート２２２は、駆動信号及び遅延回路２２１により遅延された駆動信号の論理積演算を行うゲートである。ＡＮＤゲート２２２の出力が発光信号に該当する。 The delay circuit 221 is a circuit that delays the drive signal based on the light emission period adjustment signal. The AND gate 222 is a gate that performs an AND operation of the drive signal and the drive signal delayed by the delay circuit 221. The output of the AND gate 222 corresponds to the light emission signal.
　［発光信号の生成］
　図１４Ｂは、本開示の第４の実施形態に係る発光信号の生成の一例を示す図である。同図の「駆動信号」は、駆動信号の波形を表す。また、同図の「遅延回路出力」は、遅延回路２２１の出力信号の波形を表す。また、同図の「発光信号」は、ＡＮＤゲート２２２の出力信号である発光信号の波形を表す。 [Generation of light emission signal]
FIG. 14B is a diagram illustrating an example of generation of a light emission signal according to the fourth embodiment of the present disclosure. "Drive signal" in the figure represents the waveform of the drive signal. Further, "delay circuit output" in the figure represents the waveform of the output signal of the delay circuit 221. Further, “light emission signal” in the figure represents the waveform of the light emission signal that is the output signal of the AND gate 222.
　同図において、駆動信号としてパルス幅２ｎｓの信号を想定する。また、同図の遅延回路出力の波形は、遅延回路２２１が駆動信号を１ｎｓ遅延させる例を表したものである。これら２つ信号波形を論理積演算することにより、発光信号を生成することができる。同図に表したように、この発光信号は、遅延回路２２１の遅延時間に応じてバルス幅が変化する信号である。 In the figure, a signal with a pulse width of 2 ns is assumed as the drive signal. Further, the waveform of the delay circuit output in the figure represents an example in which the delay circuit 221 delays the drive signal by 1 ns. A light emission signal can be generated by performing an AND operation on these two signal waveforms. As shown in the figure, this light emission signal is a signal whose pulse width changes according to the delay time of the delay circuit 221.
　本開示の第４の実施形態の発光電流調整部３０は、発光素子数に応じた発光期間調整信号を出力する。この発光期間調整信号は、例えば、図４に表した調整値に応じたパルス幅のとなる遅延時間を指示する信号となる。この発光期間調整信号が遅延回路２２１に入力され、発光信号のパルス幅が調整される。例えば、発光素子数が「１」の場合には、発光信号のパルス幅を５％減じる調整が行われる。これにより、発光期間における光源装置１０の光量の総和（積算値）を平準化することができる。 The light emission current adjustment section 30 of the fourth embodiment of the present disclosure outputs a light emission period adjustment signal according to the number of light emitting elements. This light emission period adjustment signal is, for example, a signal instructing a delay time at which the pulse width corresponds to the adjustment value shown in FIG. 4. This light emission period adjustment signal is input to the delay circuit 221, and the pulse width of the light emission signal is adjusted. For example, when the number of light emitting elements is "1", adjustment is made to reduce the pulse width of the light emission signal by 5%. Thereby, the total sum (integrated value) of the light amount of the light source device 10 during the light emission period can be equalized.
　これ以外の光源装置１０の構成は本開示の第１の実施形態における光源装置１０の構成と同様であるため、説明を省略する。 The configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
　このように、本開示の第４の実施形態の光源装置１０は、発光素子１０１等の発光素子数に応じて発光期間を調整する。これにより、発光期間における光量の総和の変化を低減することができる。 In this way, the light source device 10 according to the fourth embodiment of the present disclosure adjusts the light emission period according to the number of light emitting elements such as the light emitting element 101. This makes it possible to reduce changes in the total amount of light during the light emission period.
　（５．第５の実施形態）
　上述の第１の実施形態の光源装置１０に過電流検出部を付加する例について説明する。 (5. Fifth embodiment)
An example in which an overcurrent detection section is added to the light source device 10 of the first embodiment described above will be described.
　［光源装置の構成］
　図１５は、本開示の第５の実施形態に係る光源装置の構成例を示す図である。同図は、図１と同様に、光源装置１０の構成例を表す図である。同図の光源装置１０は、過電流検出部６０及び閾値調整部７０を更に備える点で、図１の光源装置１０と異なる。 [Configuration of light source device]
FIG. 15 is a diagram illustrating a configuration example of a light source device according to a fifth embodiment of the present disclosure. This figure, like FIG. 1, is a diagram showing a configuration example of the light source device 10. The light source device 10 shown in FIG. 1 differs from the light source device 10 shown in FIG. 1 in that it further includes an overcurrent detection section 60 and a threshold value adjustment section 70.
　過電流検出部６０は、抵抗６３及び６４と、ＭＯＳトランジスタ６１及び６２と、定電流回路６５と、比較器６６とを備える。ＭＯＳトランジスタ６１及び６２は、ｎチャネルＭＯＳトランジスタを使用することができる。抵抗６３の一端は電源線Ｖｄｄに接続され、他の一端はＭＯＳトランジスタ６１のドレイン及び比較器６６の比較入力に接続される。ＭＯＳトランジスタ６１のソースはＭＯＳトランジスタ６２のドレインに接続され、ＭＯＳトランジスタ６２のソースは接地される。ＭＯＳトランジスタ６１のゲートはＭＯＳトランジスタ１４のドレインに接続され、ＭＯＳトランジスタ６２のゲートは電源線Ｖｄｄに接続される。抵抗６４の一端は電源線Ｖｄｄに接続され、他の一端は定電流回路６５のシンク側端子及び比較器６６の参照入力に接続される。定電流回路６５のソース側端子は、接地される。 The overcurrent detection section 60 includes resistors 63 and 64, MOS transistors 61 and 62, a constant current circuit 65, and a comparator 66. MOS transistors 61 and 62 can be n-channel MOS transistors. One end of the resistor 63 is connected to the power supply line Vdd, and the other end is connected to the drain of the MOS transistor 61 and the comparison input of the comparator 66. The source of MOS transistor 61 is connected to the drain of MOS transistor 62, and the source of MOS transistor 62 is grounded. The gate of MOS transistor 61 is connected to the drain of MOS transistor 14, and the gate of MOS transistor 62 is connected to power supply line Vdd. One end of the resistor 64 is connected to the power supply line Vdd, and the other end is connected to the sink side terminal of the constant current circuit 65 and the reference input of the comparator 66. The source side terminal of the constant current circuit 65 is grounded.
　定電流回路６５は、閾値調整部７０からの制御信号に基づく定電流を供給する回路である。定電流回路６５のシンク側端子の電位は、過電流検出の閾値電圧となる。また、ＭＯＳトランジスタ６１のドレインの電位は、発光電流に応じた電位となる。比較器６６は、参照入力に入力される閾値電圧と比較入力に入力される発光電流に応じた電圧とを比較し、発光電流に応じた電圧が閾値電圧を超える場合に過電流を検出し、検出信号を出力する。このように、同図の過電流検出部６０は、発光素子１０１等の過電流を間接的に検出するものである。 The constant current circuit 65 is a circuit that supplies a constant current based on a control signal from the threshold value adjustment section 70. The potential of the sink side terminal of the constant current circuit 65 becomes a threshold voltage for overcurrent detection. Further, the potential of the drain of the MOS transistor 61 is a potential corresponding to the light emitting current. The comparator 66 compares the threshold voltage input to the reference input and the voltage corresponding to the light emission current input to the comparison input, and detects an overcurrent when the voltage according to the light emission current exceeds the threshold voltage, Outputs a detection signal. In this way, the overcurrent detection section 60 shown in the figure indirectly detects overcurrent of the light emitting element 101 and the like.
　閾値調整部７０は、発光パタンに基づいて発光素子１０１等の発光素子数を検出し、閾値を調整するものである。上述の発光電流調整部３０は、発光素子１０１等の発光素子数に応じて発光電流を調整する。そこで、閾値調整部７０を配置し、発光素子１０１等の発光素子数に応じて閾値を調整することにより、過電流検出の精度を向上させることができる。 The threshold value adjustment unit 70 detects the number of light emitting elements such as the light emitting element 101 based on the light emission pattern, and adjusts the threshold value. The light emitting current adjustment section 30 described above adjusts the light emitting current according to the number of light emitting elements such as the light emitting element 101. Therefore, by arranging the threshold value adjusting section 70 and adjusting the threshold value according to the number of light emitting elements such as the light emitting element 101, it is possible to improve the accuracy of overcurrent detection.
　これ以外の光源装置１０の構成は本開示の第１の実施形態における光源装置１０の構成と同様であるため、説明を省略する。 The configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
　このように、本開示の第５の実施形態の光源装置１０は、過電流検出部６０を備えて発光素子１０１等の発光電流の過電流を検出する。また、過電流検出の際の閾値を発光素子１０１等の発光素子数に応じて調整する。これにより、発光素子数に応じて発光電流が調整される場合であっても過電流検出の精度を向上させることができる。 As described above, the light source device 10 according to the fifth embodiment of the present disclosure includes the overcurrent detection section 60 and detects an overcurrent of the light emitting current of the light emitting element 101 and the like. Further, the threshold value for overcurrent detection is adjusted according to the number of light emitting elements such as the light emitting element 101. Thereby, even when the light emitting current is adjusted according to the number of light emitting elements, the accuracy of overcurrent detection can be improved.
　（６．変形例）
　光源装置１０の変形例について説明する。 (6. Modified example)
A modification of the light source device 10 will be described.
　［光源装置の構成］
　図１６は、本開示の実施形態の第１の変形例に係る光源装置の構成例を示す図である。同図は、図１と同様に、光源装置１０の構成例を表す図である。同図の光源装置１０は、図１のスイッチ素子１２１乃至１２３及び電流制限素子１１１乃至１１３の接続順を入れ替えて配線される例を表したものである。これに合わせて、ＭＯＳトランジスタ１１４及び１２４も入れ替えて配線される。 [Configuration of light source device]
FIG. 16 is a diagram illustrating a configuration example of a light source device according to a first modification of the embodiment of the present disclosure. This figure, like FIG. 1, is a diagram showing a configuration example of the light source device 10. The light source device 10 shown in the figure represents an example in which the switching elements 121 to 123 and the current limiting elements 111 to 113 shown in FIG. 1 are wired with the connection order reversed. Accordingly, the MOS transistors 114 and 124 are also wired interchangeably.
　図１７は、本開示の実施形態の第２の変形例に係る光源装置の構成例を示す図である。同図は、図１と同様に、光源装置１０の構成例を表す図である。同図の光源装置１０は、ｐチャネルＭＯＳトランジスタのスイッチ素子１２５乃至１２７及び電流制限素子１１５乃至１１７を使用する場合に例を表したものである。また、発光電流制御部４０のＭＯＳトランジスタ１１８及びＭＯＳトランジスタ１１８のソースに接続されるＭＯＳトランジスタ１２８にもｐチャネルＭＯＳトランジスタを使用する。 FIG. 17 is a diagram illustrating a configuration example of a light source device according to a second modification of the embodiment of the present disclosure. This figure, like FIG. 1, is a diagram showing a configuration example of the light source device 10. The light source device 10 shown in the figure represents an example in which switching elements 125 to 127 and current limiting elements 115 to 117 of p-channel MOS transistors are used. Further, p-channel MOS transistors are also used for the MOS transistor 118 of the light emission current control section 40 and the MOS transistor 128 connected to the source of the MOS transistor 118.
　これ以外の光源装置１０の構成は本開示の第１の実施形態における光源装置１０の構成と同様であるため、説明を省略する。 The configuration of the light source device 10 other than this is the same as the configuration of the light source device 10 in the first embodiment of the present disclosure, so a description thereof will be omitted.
　（７．発光素子の構成）
　発光素子１０１等の構成について説明する。 (7. Configuration of light emitting element)
The configuration of the light emitting element 101 and the like will be explained.
　［発光素子の構成］
　図１８Ａは、本開示の実施形態に係る発光素子の構成例を示す図である。同図は、複数の発光素子がアレイ状配置されて構成される発光素子アレイ４１０を有する発光素子チップ４００の構成例を表す図である。 [Configuration of light emitting element]
FIG. 18A is a diagram illustrating a configuration example of a light emitting element according to an embodiment of the present disclosure. This figure is a diagram illustrating a configuration example of a light emitting element chip 400 having a light emitting element array 410 configured by a plurality of light emitting elements arranged in an array.
　発光素子アレイ４１０は、発光素子であるレーザダイオード４１１が２次元行列状に配置されて構成される。このレーザダイオード４１１には、垂直共振器型面発光レーザ（ＶＣＳＥＬ：Vertical　Cavity　Surface　Emitting　Laser）を適用することができる。このレーザダイオード４１１の両側の黒丸は、接続端子４１２を表す。 The light emitting element array 410 is composed of laser diodes 411, which are light emitting elements, arranged in a two-dimensional matrix. A vertical cavity surface emitting laser (VCSEL) can be applied to the laser diode 411. Black circles on both sides of this laser diode 411 represent connection terminals 412.
　発光素子アレイ４１０は、発光素子チップ４００に実装される。この発光素子チップ４００には、図１の発光素子１０１乃至１０３以外の回路を配置することができる。発光素子チップ４００の端部にはパッド４０１が配置される。このパッド４０１及び接続端子４１２の間は、ボンディングワイヤにより接続することができる。 The light emitting element array 410 is mounted on the light emitting element chip 400. Circuits other than the light emitting elements 101 to 103 in FIG. 1 can be arranged in this light emitting element chip 400. A pad 401 is arranged at an end of the light emitting element chip 400. The pad 401 and the connection terminal 412 can be connected by a bonding wire.
　図１８Ｂは、本開示の実施形態に係る発光素子の他の構成例を示す図である。同図は、発光素子アレイ４１０の裏面に配置されるバンプ４１３を介して発光素子チップ４００と接続される例を表したものである。 FIG. 18B is a diagram illustrating another configuration example of the light emitting element according to the embodiment of the present disclosure. This figure shows an example in which a light emitting element array 410 is connected to a light emitting element chip 400 via bumps 413 arranged on the back surface thereof.
　［発光素子の発光例］
　図１９Ａ及び１９Ｂは、本開示の実施形態に係る発光素子の発光の一例を示す図である。同図は、発光素子アレイ４１０の発光の一例を表した図である。同図において、斜線ハッチングを付したレーザダイオード４１１は、発光状態のレーザダイオード４１１を表す。 [Example of light emission of light emitting element]
19A and 19B are diagrams illustrating an example of light emission of a light emitting element according to an embodiment of the present disclosure. This figure is a diagram showing an example of light emission from the light emitting element array 410. In the figure, a diagonally hatched laser diode 411 represents the laser diode 411 in a light emitting state.
　図１９Ａは、隣接するレーザダイオード４１１を発光させる例を表したものである。また、図１９Ｂは、発光させるレーザダイオード４１１を分散させる例を表したものである。 FIG. 19A shows an example in which adjacent laser diodes 411 are caused to emit light. Further, FIG. 19B shows an example in which the laser diodes 411 that emit light are dispersed.
　（８．測距装置への適用例）
　［測距装置の構成］
　図２０は、本開示の実施形態に係る光源装置を適用可能な測距装置の構成例を示す図である。同図は、測距装置７００の構成例を表す図である。測距装置７００は、対象物との距離を測定する装置である。同図の測距装置７００は、物体７０１との間の距離を測定する例を表したものである。測距装置７００は、光源装置７１０と、光検出素子７２０と、測距部７３０と、制御部７４０とを備える。なお、同図の白抜きの矢印は、光の伝達を表す。同図において、測距装置７００の光源装置７１０から出射された出射光７０２が物体７０１により反射されて反射光７０３を生じる。この反射光７０３が測距装置７００に到達して光検出素子７２０により検出される。この出射光７０２の出射から反射光７０３の検出までの時間（飛行時間）を計時することにより、測距装置７００から物体７０１までの距離を測定することができる。 (8. Application example to distance measuring device)
[Configuration of ranging device]
FIG. 20 is a diagram illustrating a configuration example of a distance measuring device to which the light source device according to the embodiment of the present disclosure can be applied. This figure is a diagram showing an example of the configuration of a distance measuring device 700. The distance measuring device 700 is a device that measures the distance to an object. A distance measuring device 700 in the figure represents an example of measuring the distance to an object 701. The distance measuring device 700 includes a light source device 710, a light detection element 720, a distance measuring section 730, and a control section 740. Note that the white arrows in the figure represent the transmission of light. In the figure, emitted light 702 emitted from a light source device 710 of a distance measuring device 700 is reflected by an object 701 to generate reflected light 703. This reflected light 703 reaches the distance measuring device 700 and is detected by the photodetecting element 720. By measuring the time (flight time) from the emission of the emitted light 702 to the detection of the reflected light 703, the distance from the distance measuring device 700 to the object 701 can be measured.
　光源装置７１０は、測距の対象物に光を照射するものである。なお、光源装置７１０には、上述の光源装置１０を適用することができる。 The light source device 710 irradiates light onto the object to be measured. Note that the above-described light source device 10 can be applied to the light source device 710.
　光検出素子７２０は、入射光に応じた画像信号を生成する複数の画素を備えるものである。この光検出素子７２０は、例えば、ＣＭＯＳ（Complementary　Metal　Oxide　Semiconductor）型の撮像素子により構成することができる。光検出素子７２０は、出射光７０２の発光期間及び非発光期間に同期する期間に受光した反射光７０３の撮像を行い、画像信号を生成する。光検出素子７２０は、生成した画像信号を測距部７３０に対して出力する。 The photodetector element 720 includes a plurality of pixels that generate image signals according to incident light. This photodetecting element 720 can be configured by, for example, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor. The photodetecting element 720 images the reflected light 703 received during a period synchronized with the light emitting period and the non-emitting period of the emitted light 702, and generates an image signal. Photodetection element 720 outputs the generated image signal to distance measuring section 730.
　測距部７３０は、物体７０１までの距離を測定するものである。この測距部７３０は、光検出素子７２０から出力される画像信号に基づいて上述の飛行時間の計時を行って距離を測定する。測距部７３０により計測された距離は、距離データとして測距装置７００の外部に出力される。 The distance measuring unit 730 measures the distance to the object 701. The distance measuring section 730 measures the distance by measuring the flight time described above based on the image signal output from the photodetecting element 720. The distance measured by the distance measuring unit 730 is output to the outside of the distance measuring device 700 as distance data.
　制御部７４０は、測距装置７００の全体を制御するものである。例えば、制御部７４０は、光源装置７１０に対して光の出射を指示するとともに、光の出射開始を測距部７３０に対して通知する。この通知により、測距部７３０が飛行時間の計時を開始する。また、制御部７４０は、光検出素子７２０に対して画像信号の生成等の制御を行う。制御部７４０は、制御信号を出力することにより、光源装置７１０等の制御を行う。 The control unit 740 controls the entire distance measuring device 700. For example, the control unit 740 instructs the light source device 710 to emit light, and notifies the ranging unit 730 of the start of light emission. In response to this notification, the ranging section 730 starts measuring the flight time. Further, the control unit 740 controls the photodetection element 720, such as generation of an image signal. The control unit 740 controls the light source device 710 and the like by outputting a control signal.
　なお、本明細書に記載された効果はあくまで例示であって限定されるものでは無く、また他の効果があってもよい。 Note that the effects described in this specification are merely examples and are not limiting, and other effects may also exist.
　なお、本技術は以下のような構成も取ることができる。
（１）
　複数の発光素子と、
　前記複数の発光素子毎に直列に接続されて発光期間に発光電流を流す複数のスイッチ素子と、
　前記複数のスイッチ素子を制御することにより前記複数の発光素子の発光を制御する発光制御部と、
　前記複数の発光素子毎に配置されて発光素子に流れる電流を前記発光電流に制限する複数の電流制限素子と、
　前記発光電流に応じた電流制御信号を前記複数の電流制限素子の制御端子に供給する発光電流制御部と、
　前記複数の発光素子のうちの発光させる発光素子数に応じて前記発光電流を調整する発光電流調整部と
　を有する光源装置。
（２）
　前記発光電流調整部は、前記発光電流制御部における前記発光電流の値を調整することにより前記発光を調整する前記（１）に記載の光源装置。
（３）
　前記電流制限素子は、ゲートを前記制御端子とするＭＯＳトランジスタにより構成され、
　前記発光電流制御部は、前記複数の電流制限素子とカレントミラー回路を構成するＭＯＳトランジスタを備えて当該ＭＯＳトランジスタのゲート電圧を前記電流制御信号として前記複数の電流制限素子に供給し、
　前記発光電流調整部は、前記発光電流制御部における前記カレントミラー回路の参照電流を調整することにより前記発光電流の値を調整する
　前記（２）に記載の光源装置。
（４）
　前記発光電流調整部は、前記発光制御部における発光期間を調整することにより前記発光電流を調整する前記（１）に記載の光源装置。
（５）
　前記複数の発光素子は、複数の領域に分割されて配置される前記（１）から（４）の何れかに記載の光源装置。
（６）
　前記発光電流調整部は、複数の前記領域毎に前記発光電流を調整する前記（５）に記載の光源装置。
（７）
　前記発光電流の過電流を所定の閾値に基づいて検出する過電流検出部と、
　前記発光素子数に応じて前記閾値を調整する閾値調整部と
　を更に有する前記（１）から（６）の何れかに記載の光源装置。
（８）
　複数の発光素子と、
　前記複数の発光素子毎に直列に接続されて発光期間に発光電流を流す複数のスイッチ素子と、
　前記複数のスイッチ素子を制御することにより前記複数の発光素子の発光を制御する発光制御部と、
　前記複数の発光素子毎に配置されて発光素子に流れる電流を前記発光電流に制限する複数の電流制限素子と、
　前記発光電流に応じた電流制御信号を前記複数の電流制限素子の制御端子に供給する発光電流制御部と、
　前記複数の発光素子のうちの発光させる発光素子数に応じて前記発光電流を調整する発光電流調整部と
　を備える光源装置と、
　前記光源装置から出射された光が対象物に反射された反射光を検出する光検出素子と、
　前記光の出射から前記反射光の検出までの時間を測定することにより前記対象物までの距離を測定する測距部と
　を有する測距装置。 Note that the present technology can also have the following configuration.
(1)
multiple light emitting elements;
a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emission current to flow during a light emission period;
a light emission control unit that controls light emission of the plurality of light emitting elements by controlling the plurality of switch elements;
a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current;
a light emission current control unit that supplies a current control signal according to the light emission current to control terminals of the plurality of current limiting elements;
and a light emitting current adjustment section that adjusts the light emitting current according to the number of light emitting elements that emit light among the plurality of light emitting elements.
(2)
The light source device according to (1), wherein the light emission current adjustment section adjusts the light emission by adjusting the value of the light emission current in the light emission current control section.
(3)
The current limiting element is constituted by a MOS transistor whose gate is the control terminal,
The light emission current control unit includes a MOS transistor forming a current mirror circuit with the plurality of current limiting elements, and supplies a gate voltage of the MOS transistor to the plurality of current limiting elements as the current control signal,
The light source device according to (2), wherein the light emission current adjustment section adjusts the value of the light emission current by adjusting a reference current of the current mirror circuit in the light emission current control section.
(4)
The light source device according to (1), wherein the light emission current adjustment section adjusts the light emission current by adjusting a light emission period in the light emission control section.
(5)
The light source device according to any one of (1) to (4), wherein the plurality of light emitting elements are divided and arranged into a plurality of regions.
(6)
The light source device according to (5), wherein the light emitting current adjustment section adjusts the light emitting current for each of the plurality of regions.
(7)
an overcurrent detection unit that detects an overcurrent of the light emitting current based on a predetermined threshold;
The light source device according to any one of (1) to (6), further comprising: a threshold adjustment section that adjusts the threshold according to the number of light emitting elements.
(8)
multiple light emitting elements;
a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emission current to flow during a light emission period;
a light emission control unit that controls light emission of the plurality of light emitting elements by controlling the plurality of switch elements;
a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current;
a light emission current control unit that supplies a current control signal according to the light emission current to control terminals of the plurality of current limiting elements;
a light source device comprising: a light emitting current adjustment section that adjusts the light emitting current according to the number of light emitting elements to emit light among the plurality of light emitting elements;
a photodetection element that detects reflected light emitted from the light source device and reflected by a target object;
A distance measuring device, comprising: a distance measuring section that measures a distance to the object by measuring a time from emission of the light to detection of the reflected light.
　１０　光源装置
　２０　発光制御部
　３０　発光電流調整部
　４０　発光電流制御部
　６０　過電流検出部
　１００、１５０　領域
　１０１～１０３、１５１～１５３　発光素子
　１１１～１１３、１１５～１１７、１６１～１６３　電流制限素子
　１２１～１２３、１２５～１２７、１７１～１７３　スイッチ素子
　７００　測距装置
　７１０　光源装置
　７２０　光検出素子
　７３０　測距部 10 light source device 20 light emission control section 30 light emission current adjustment section 40 light emission current control section 60 overcurrent detection section 100, 150 regions 101 to 103, 151 to 153 light emitting elements 111 to 113, 115 to 117, 161 to 163 current limiting element 121 ~123, 125-127, 171-173 Switch element 700 Distance measuring device 710 Light source device 720 Photodetecting element 730 Distance measuring section

Claims (8)

  1. 　複数の発光素子と、
    　前記複数の発光素子毎に直列に接続されて発光期間に発光電流を流す複数のスイッチ素子と、
    　前記複数のスイッチ素子を制御することにより前記複数の発光素子の発光を制御する発光制御部と、
    　前記複数の発光素子毎に配置されて発光素子に流れる電流を前記発光電流に制限する複数の電流制限素子と、
    　前記発光電流に応じた電流制御信号を前記複数の電流制限素子の制御端子に供給する発光電流制御部と、
    　前記複数の発光素子のうちの発光させる発光素子数に応じて前記発光電流を調整する発光電流調整部と
    　を有する光源装置。     multiple light emitting elements;
    a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emission current to flow during a light emission period;
    a light emission control unit that controls light emission of the plurality of light emitting elements by controlling the plurality of switch elements;
    a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current;
    a light emission current control unit that supplies a current control signal according to the light emission current to control terminals of the plurality of current limiting elements;
    and a light emitting current adjustment section that adjusts the light emitting current according to the number of light emitting elements that emit light among the plurality of light emitting elements.
  2. 　前記発光電流調整部は、前記発光電流制御部における前記発光電流の値を調整することにより前記発光を調整する請求項１に記載の光源装置。 The light source device according to claim 1, wherein the light emission current adjustment section adjusts the light emission by adjusting the value of the light emission current in the light emission current control section.
  3. 　前記電流制限素子は、ゲートを前記制御端子とするＭＯＳトランジスタにより構成され、
    　前記発光電流制御部は、前記複数の電流制限素子とカレントミラー回路を構成するＭＯＳトランジスタを備えて当該ＭＯＳトランジスタのゲート電圧を前記電流制御信号として前記複数の電流制限素子に供給し、
    　前記発光電流調整部は、前記発光電流制御部における前記カレントミラー回路の参照電流を調整することにより前記発光電流の値を調整する
    　請求項２に記載の光源装置。     The current limiting element is constituted by a MOS transistor whose gate is the control terminal,
    The light emission current control unit includes a MOS transistor forming a current mirror circuit with the plurality of current limiting elements, and supplies a gate voltage of the MOS transistor to the plurality of current limiting elements as the current control signal,
    The light source device according to claim 2, wherein the light emission current adjustment section adjusts the value of the light emission current by adjusting a reference current of the current mirror circuit in the light emission current control section.
  4. 　前記発光電流調整部は、前記発光制御部における発光期間を調整することにより前記発光電流を調整する請求項１に記載の光源装置。 The light source device according to claim 1, wherein the light emission current adjustment section adjusts the light emission current by adjusting a light emission period in the light emission control section.
  5. 　前記複数の発光素子は、複数の領域に分割されて配置される請求項１に記載の光源装置。 The light source device according to claim 1, wherein the plurality of light emitting elements are divided and arranged into a plurality of regions.
  6. 　前記発光電流調整部は、複数の前記領域毎に前記発光電流を調整する請求項５に記載の光源装置。 The light source device according to claim 5, wherein the light emitting current adjustment section adjusts the light emitting current for each of the plurality of regions.
  7. 　前記発光電流の過電流を所定の閾値に基づいて検出する過電流検出部と、
    　前記発光素子数に応じて前記閾値を調整する閾値調整部と
    　を更に有する請求項１に記載の光源装置。     an overcurrent detection unit that detects an overcurrent of the light emitting current based on a predetermined threshold;
    The light source device according to claim 1, further comprising: a threshold value adjustment section that adjusts the threshold value according to the number of light emitting elements.
  8. 　複数の発光素子と、
    　前記複数の発光素子毎に直列に接続されて発光期間に発光電流を流す複数のスイッチ素子と、
    　前記複数のスイッチ素子を制御することにより前記複数の発光素子の発光を制御する発光制御部と、
    　前記複数の発光素子毎に配置されて発光素子に流れる電流を前記発光電流に制限する複数の電流制限素子と、
    　前記発光電流に応じた電流制御信号を前記複数の電流制限素子の制御端子に供給する発光電流制御部と、
    　前記複数の発光素子のうちの発光させる発光素子数に応じて前記発光電流を調整する発光電流調整部と
    　を備える光源装置と、
    　前記光源装置から出射された光が対象物に反射された反射光を検出する光検出素子と、
    　前記光の出射から前記反射光の検出までの時間を測定することにより前記対象物までの距離を測定する測距部と
    　を有する測距装置。     multiple light emitting elements;
    a plurality of switch elements connected in series to each of the plurality of light emitting elements and causing a light emission current to flow during a light emission period;
    a light emission control unit that controls light emission of the plurality of light emitting elements by controlling the plurality of switch elements;
    a plurality of current limiting elements arranged for each of the plurality of light emitting elements to limit the current flowing through the light emitting elements to the light emitting current;
    a light emission current control unit that supplies a current control signal according to the light emission current to control terminals of the plurality of current limiting elements;
    a light source device comprising: a light emitting current adjustment section that adjusts the light emitting current according to the number of light emitting elements to emit light among the plurality of light emitting elements;
    a photodetection element that detects reflected light emitted from the light source device and reflected by a target object;
    A distance measuring device, comprising: a distance measuring section that measures a distance to the object by measuring a time from emission of the light to detection of the reflected light.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11291550A (en) * 1998-02-10 1999-10-26 Oki Data Corp Drive circuit
US20140232278A1 (en) * 2010-12-11 2014-08-21 Jae Hong Jeong Light emitting diode driver
WO2014126258A1 (en) * 2013-02-18 2014-08-21 シチズンホールディングス株式会社 Led drive circuit
JP2016081739A (en) * 2014-10-17 2016-05-16 ローム株式会社 Light-emitting element drive device, light-emitting device and vehicle
JP2020126947A (en) * 2019-02-05 2020-08-20 ソニーセミコンダクタソリューションズ株式会社 Light source device and electronic equipment

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11291550A (en) * 1998-02-10 1999-10-26 Oki Data Corp Drive circuit
US20140232278A1 (en) * 2010-12-11 2014-08-21 Jae Hong Jeong Light emitting diode driver
WO2014126258A1 (en) * 2013-02-18 2014-08-21 シチズンホールディングス株式会社 Led drive circuit
JP2016081739A (en) * 2014-10-17 2016-05-16 ローム株式会社 Light-emitting element drive device, light-emitting device and vehicle
JP2020126947A (en) * 2019-02-05 2020-08-20 ソニーセミコンダクタソリューションズ株式会社 Light source device and electronic equipment

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