Lidar device and information generation method therefor

Abstract

The objective of the present invention is to provide an optical output device and a LiDAR device, the optical output device comprising: a VCSEL; a comparator, which compares the output of a cathode terminal of the VCSEL to a reference value so as to generate a square wave; and a control unit, which counts the output of the comparator so as to determine whether the VCSEL is abnormal, wherein the operation of the VCSEL is monitored so that an abnormal operation thereof can be detected.

Description

Lidar device and method for generating information thereof

[0001] The present invention relates to a lidar device and a method for generating information thereof.

[0002] LiDAR (Light Detection and Ranging) devices measure the distance to a target object or create a shape using laser pulses that are emitted from the device and then reflected back from the target object. LiDAR devices are applied to various technical fields that require 3D imaging. For example, LiDAR can be applied to various fields such as meteorology, aviation, space, and automotive. Recently, the role of LiDAR in the autonomous driving field has been rapidly increasing.

[0003] In general, the light emitting unit of the lidar device generates an output light signal and irradiates it on an object, the light receiving unit receives an input light signal reflected from the object, and the information generating unit generates information about the object using the input light signal received by the light receiving unit.

[0004] The light-emitting part of the LiDAR device includes a scanner, and the scanner scans an area of ​​a preset field of view (FOV). Meanwhile, the light-emitting part of the LiDAR device counts (or counts) the triggers output from the light-receiving part to detect whether the light signal is properly output, but this has the problem of low accuracy. In addition to accuracy, the light-emitting part of the LiDAR device must also consider resolution, and when the LiDAR device measures the distance to a distant object or visualizes it, it must output a signal with a high output, so stability must also be considered.

[0005] The technical problem to be achieved by the present invention is to provide a light transmitting device capable of detecting abnormal operation by monitoring the operation of a VCSEL (Vertical Cavity Surface Emitting Laser) in a control unit, and a lidar device including the same.

[0006] According to an embodiment of the present invention, the light output device may include a VCSEL (Vertical Cavity Surface Emitting Laser), a comparator that compares the output of a cathode terminal of the VCSEL with a reference value to generate a square wave, and a control unit that counts the output of the comparator to determine whether the VCSEL is abnormal.

[0007] The optical output device may further include a voltage divider between the output terminal of the cathode of the VCSEL and the input terminal of the comparator.

[0008] The optical output device may further include an inverting amplifier between the voltage divider and the comparator to invert the output of the voltage divider.

[0009] The optical output device may further include a level shifter between the comparator and the control unit for adjusting the output size of the comparator.

[0010] In the optical output device, the control unit can cut off the power to the VCSEL if it is determined that there is an abnormality in the VCSEL.

[0011] In the optical output device, the control unit can determine whether the VCSEL is abnormal by comparing the number of pulses transmitted through each anode of the VCSEL with the value calculated by the control unit from the output of the comparator.

[0012] In the optical output device, whether or not the above VCSEL is abnormal can be determined by determining the channel in which the abnormality occurred.

[0013] In the optical output device, the reference value can be determined based on the voltage input to the VCSEL.

[0014] According to an embodiment of the present invention, a lidar device may include an optical output device and an optical input device, and the optical output device may include a VCSEL, a comparator for generating a square wave by comparing an output of a cathode terminal of the VCSEL with a reference value, and a control unit for counting an output of the comparator to determine whether the VCSEL is abnormal.

[0015] According to an embodiment of the present invention, the control unit (or processor) can directly monitor the operation of a VCSEL (Vertical Cavity Surface Emitting Laser).

[0016] According to an embodiment of the present invention, abnormal operation of a VCSEL can be detected by monitoring the cathode terminal of the VCSEL.

[0017] According to an embodiment of the present invention, the control unit can directly monitor the operation of the VCSEL, thereby increasing accuracy and improving resolution.

[0018] According to an embodiment of the present invention, when an abnormality in the VCSEL is detected, the emission of the VCSEL can be stopped.

[0019] According to an embodiment of the present invention, the operation of a VCSEL for high-power long-distance can also be directly and safely monitored.

[0020] FIG. 1 is a block diagram of a lidar device according to one embodiment of the present invention.

[0021] FIG. 2 is a drawing showing the configuration of a VCSEL (Vertical Cavity Surface Emitting Laser), which is one of the light sources of a light emitting unit according to an embodiment of the present invention.

[0022] Figure 3 is a block diagram of an anomaly detection unit according to an embodiment of the present invention.

[0023] FIG. 4 is an example of a circuit for distributing voltage according to an embodiment of the present invention.

[0024] FIG. 5 is an example of a circuit that constitutes an inverting amplifier according to an embodiment of the present invention.

[0025] Fig. 6 is an example of a circuit constituting a comparator according to an embodiment of the present invention.

[0026] Fig. 7 is an example of a circuit that constitutes a level shifter according to an embodiment of the present invention.

[0027] FIG. 8 is a diagram showing the results of simulating the voltage of the output terminal of each component included in the anomaly detection unit according to an embodiment of the present invention.

[0028] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0029] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0030] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0031] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0032] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0033] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

[0034] These terms are intended only to distinguish one component from another, and are not intended to limit the nature, order, or sequence of the component.

[0035] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0036] Additionally, when described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0037] The lidar device according to an embodiment of the present invention may refer to a lidar device mounted on a vehicle to measure the distance between the vehicle and an object, but is not limited thereto. The lidar device according to an embodiment of the present invention may extract depth information using the ToF (Time of Flight) principle or the FMCW (Frequency Modulation Continuous Wave) principle. In this specification, the lidar device may also be referred to as an information generating device, a depth information generating device, or a camera device.

[0038] FIG. 1 is a block diagram of a lidar device according to one embodiment of the present invention.

[0039] Referring to FIG. 1, a lidar device (1000) according to an embodiment of the present invention includes a light emitting unit (100), a light receiving unit (200), an information generating unit (300), and a control unit (400).

[0040] The light emitting unit (100) can generate and output an output light signal in the form of a pulse wave or a continuous wave. The continuous wave may be in the form of a sinusoid wave or a square wave. By generating the output light signal in the form of a pulse wave or a continuous wave, the lidar device (1000) can detect a time difference or a phase difference between the output light signal output from the light emitting unit (100) and the input light signal reflected from the target area and then input to the light receiving unit (200). In the present specification, the output light may refer to light output from the light emitting unit (100) and incident on an object, and the input light may refer to light output from the light emitting unit (100), reaching the target area, reflected from the target area, and then input to the light receiving unit (200). In the present specification, the pattern of the output light may be referred to as an emission pattern, and the pattern of the input light may be referred to as an incident pattern. From the perspective of the target area, the output light can be incident light, and the input light can be reflected light.

[0041] The light emitting unit (100) includes a light source and a lens group.

[0042] A light source generates and outputs a laser pulse. The light source may utilize a light emitting diode (LED), and may have a form in which multiple light emitting diodes are arranged in a certain pattern. Alternatively, the light source may include an organic light emitting diode (OLED) or a laser diode (LD). Alternatively, the light source may be a vertical cavity surface emitting laser (VCSEL). A VCSEL is one of the laser diodes that converts an electrical signal into an optical signal, and can output a wavelength of about 800 to 1000 nm, for example, about 850 nm or about 940 nm. The light source generates an output optical signal in the form of a pulse wave or a continuous wave by repeatedly blinking (on / off) at a certain time interval. The certain time interval may be the frequency of the output optical signal.

[0043] A lens group can collect light output from a light source and output the collected light to the outside. The lens group can be arranged above the light source and spaced apart from the light source. Here, the above of the light source can mean the side from which light is output from the light source. The lens group can include at least one lens, and when the lens group includes a plurality of lenses, each lens can be aligned with respect to a central axis to form an optical system. Here, the central axis can be identical to the optical axis of the optical system. The lens group can also include a diffusion member that receives light output from the light source and then outputs the received light by refracting or diffracting the received light.

[0044] The light receiving unit (200) can receive an optical signal reflected from the target area. At this time, the received optical signal may be an optical signal output by the light emitting unit (100) reflected from the target area.

[0045] The light receiving unit (200) includes an image sensor, a filter placed on the image sensor, and a lens group placed on the filter.

[0046] An optical signal reflected from a target area can pass through a lens group of a light-receiving unit (200). The optical axis of the lens group of the light-receiving unit (200) can be aligned with the optical axis of the image sensor. A filter can be arranged between the lens group of the light-receiving unit (200) and the image sensor. The filter can be arranged on an optical path between the target area and the image sensor. The filter can filter light having a predetermined wavelength range. The filter can pass light of a specific wavelength. For example, the filter can pass light in an infrared band and block light outside of an infrared band. The image sensor can receive an optical signal and output the received optical signal as an electrical signal. The image sensor can detect light of a wavelength corresponding to the wavelength of light output by the light-emitting unit (100). For example, the image sensor can detect light in an infrared band.

[0047] An image sensor may be configured with a structure in which multiple pixels are arranged in a grid shape.

[0048] The light receiving unit (200) and the light emitting unit (100) can be arranged side by side. The light receiving unit (200) can be arranged next to the light emitting unit (100). The light receiving unit (200) can be arranged in the same direction as the light emitting unit (100).

[0049] The information generating unit (300) generates information about a target area using an input light signal input to the light receiving unit (200). The information about the target area may include three-dimensional information about the target area. For example, the information about the target area may include depth information about the target area. For example, the information generating unit (300) may calculate depth information about an object using the flight time it takes for an output light signal output from the light emitting unit (100) to be input to the light receiving unit (200) after being reflected from an object. For example, the information generating unit (300) may calculate a time difference between an output light signal and an input light signal using an electrical signal received by an image sensor, and may calculate a distance between the target area and the LIDAR device (1000) using the calculated time difference. For example, the information generating unit (300) may calculate a phase difference between an output light signal and an input light signal using an electrical signal received from an image sensor, and may calculate a distance between the target area and the LIDAR device (1000) using the calculated phase difference.

[0050] The control unit (400) (or processor) controls the operation of the light emitting unit (100), the light receiving unit (200), and the information generating unit (300). The information generating unit (300) and the control unit (400) may be implemented in the form of a PCB (printed circuit board). In addition, the information generating unit (300) and the control unit (400) may be implemented in the form of other configurations. Alternatively, the control unit (400) may be included in a terminal or vehicle in which the lidar device (1000) according to an embodiment of the present invention is installed. For example, the control unit (400) may be implemented in the form of an application processor (AP) of a smartphone in which the lidar device (1000) according to an embodiment of the present invention is installed, or in the form of an electronic control unit (ECU) of a vehicle in which the lidar device (1000) according to an embodiment of the present invention is installed.

[0051] The lidar device (1000) according to an embodiment of the present invention may be a solid-state lidar. Unlike a mechanical lidar that rotates 360°, the solid-state lidar does not include a mechanical part for rotating the lidar device (1000), and thus has the advantage of being inexpensive and being able to be implemented in a small size. The solid-state lidar may be, for example, one of a MEMS (Micro Electro Mechanical System) lidar, a flash lidar, and an OPA (Optical Phase Array) lidar. In a MEMS lidar, the tilt angle of a mirror can be slightly changed by an electrical signal. In a flash lidar, an optical flash is used, and a single large-area laser pulse can illuminate the forward environment. In an OPA, an optical phase modulator controls the speed of light passing through a lens, and thus the optical wavefront shape can be controlled.

[0052] According to an embodiment of the present invention, in order to implement a fixed lidar, the light emitting unit (100) may include a scanner. In a fixed lidar, the scanner may include a mirror or a diffusion member and may be implemented in the form of a chip.

[0053] Meanwhile, according to an embodiment of the present invention, the light emitting unit (100) of the lidar device (1000) irradiates an output light signal to a target area. Here, the target area may correspond to an area of ​​a field of view (FOV) preset for the light emitting unit (100). The farther away from the lidar device (1000), the larger the area of ​​the target area corresponding to the FOV, and the larger the area of ​​the target area, the longer the time required for the light emitting unit (100) to scan the target area, and the more power is consumed.

[0054] According to one embodiment, the lidar device (1000) can determine whether the VCSEL is operating normally when the light-emitting unit (100) includes a VCSEL as a light source. The control unit (400) of the lidar device (1000) can determine whether the VCSEL of the light-emitting unit (100) is operating normally by counting a trigger signal from the light-receiving unit (200). However, in the embodiment of the present invention, the control unit (400) can directly count an output light signal (or, a laser pulse, a signal from a cathode terminal) output from the VCSEL of the light-emitting unit (100) to determine whether the VCSEL of the light-emitting unit (100) is operating normally.

[0055] Hereinafter, the configuration and operation of an abnormality detection unit (not shown) for directly counting the output light signal output from the VCSEL of the light emitting unit (100) to clearly determine whether the VCSEL of the light emitting unit (100) is operating normally will be described in detail. According to one embodiment, the abnormality detection unit may be included in the lidar device (1000) as a separate configuration, but may also be a configuration included in the light emitting unit (100).

[0056] First, if we look at the configuration of VCSEL, which is one of the light sources of the light emitting unit, it can be as shown in Fig. 2.

[0057] FIG. 2 is a diagram showing the configuration of a VCSEL, which is one of the light sources of a light-emitting unit according to an embodiment of the present invention. The VCSEL may be composed of a plurality of anodes (e.g., 56) and one cathode. The plurality of anodes may be connected to one cathode, and when the voltage of the anode is higher than a predetermined value, light may be transmitted to the cathode. Each of the plurality of anodes may be one channel, and each channel may generate and transmit approximately 200 pulses for 600 μs. In addition, one frame in which all channels generate and transmit pulses may be 50 ms.

[0058] By generating pulses at high speed and transmitting them from the anode to the cathode, the voltage output to the cathode terminal of the VCSEL can also be in the form of a pulse that switches at high speed. However, the voltage output to the cathode terminal of the VCSEL may contain noise, and the waveform may be distorted due to the rising and / or falling times of the pulse.

[0059] Accordingly, in order for the control unit (400) to count the signal output from the cathode terminal of the VCSEL, it is necessary to convert the form of the signal output from the cathode terminal of the VCSEL into a form that is easy to count, for example, a square wave.

[0060] The control unit (400) can not only turn the VCSEL on / off, but also set the signal transmitted to the anode terminal of the VCSEL. For example, the control unit (400) can set the intensity of the signal (i.e., voltage) transmitted to the anode terminal of the VCSEL. The control unit (400) can set the intensity of the voltage to be output by the VCSEL to be stronger when the object is far away than when the object is close. In addition, the control unit (400) can also set the number of pulses constituting the channel, the length of one frame, etc.

[0061] FIG. 3 is a block diagram of an anomaly detection unit according to one embodiment of the present invention, and FIGS. 4 to 7 show examples of circuits for performing the functions of each component of the anomaly detection unit.

[0062] Referring to FIG. 3, an abnormality detection unit (500) according to one embodiment of the present invention may include a voltage divider (510), an inverting amplifier (520), a comparator (530), and a level shifter (540). The voltage divider (510) of the abnormality detection unit (500) may be connected to the light emitting unit (100), and the level shifter (540) of the abnormality detection unit (500) may be connected to the control unit (400).

[0063] The voltage divider (510) can output a voltage proportional to the input voltage. The input terminal (511) of the voltage divider (510) can be connected to the light-emitting unit (100), and the voltage input to the voltage divider (510) can be a voltage output from the light-emitting unit (100). According to one embodiment, a coupling capacitor can be included between the light-emitting unit (100) and the input terminal (511) of the voltage divider (510). According to one embodiment, the voltage output from the light-emitting unit (100) can be a voltage of a cathode terminal of a VCSEL. In order for the lidar device (1000) to measure the distance to a distant target object or to shape the target object, the light emitting unit (100) must generate and output a high-output light signal. Therefore, the anomaly detection unit (500) can use the voltage divider (510) to control the voltage of the signal output from the light emitting unit (100) in order to monitor the output light signal output from the light emitting unit (100). For example, the voltage divider (510) can lower the voltage output according to the specifications of the elements (or components) after the voltage divider (510). The output light signal output at a high output by the voltage divider (510) can also be safely directly measured or monitored. If the voltage divider (510) is omitted and the intensity of the output light signal output from the light emitting unit (100) is strong, not only may the elements after that not operate properly, but it may also be unsafe for the user using it. However, when the lidar device (1000) measures the distance to a target object at a close distance or shapes the target object, the intensity of the output light signal output from the light emitting unit (100) may not be large, so in this case, the voltage divider (510) may be omitted.

[0064] Fig. 4 illustrates an example of a circuit that distributes voltage, which may be a voltage divider (510) according to the present invention. However, the configuration of the voltage divider (510) according to the present invention is not limited thereto.

[0065] Referring to Fig. 4, a circuit for distributing voltage may be composed of a plurality of resistors, for example, two resistors (513, 514). Depending on the resistance value of each resistor included in the circuit, the input voltage may be reduced by a certain ratio and output.

[0066] Since the voltage at the output terminal (512) of the voltage divider (510) is a negative value, an inverting circuit is required to convert it to a positive value. In addition, if the voltage at the output terminal (512) of the voltage divider (510) is small, the output voltage needs to be amplified to distinguish between noise and the output voltage. Accordingly, the output terminal (512) of the voltage divider (510) can be connected to the input terminal (521) of the inverting amplifier (520).

[0067] The inverting amplifier (520) can invert the input voltage, amplify it, and then output it. The degree of amplification can be determined according to the magnitude of the voltage output from the voltage divider (510). According to one embodiment, if the magnitude of the voltage output from the voltage divider (510) is sufficiently large to be distinguished from noise, the amplification factor of the inverting amplifier (520) can be 1. In this case, the inverting amplifier (520) can operate as an inverter that converts the voltage from negative to positive.

[0068] Fig. 5 illustrates an example of a circuit that constitutes an inverting amplifier, which may be an inverting amplifier (520) according to the present invention. However, the configuration of the inverting amplifier (520) according to the present invention is not limited thereto.

[0069] Referring to FIG. 5, a circuit constituting an inverting amplifier (520) may include an OP-AMP, a resistor, a power source, etc. Specifically, an input terminal (521) of the inverting amplifier (520) may be connected to a (-) input terminal of the OP-AMP, and a (+) input terminal of the OP-AMP may be connected to GND. The (-) input terminal of the OP-AMP may also be connected to an output terminal of the OP-AMP together with a resistor, and the output terminal of the OP-AMP may be an output terminal (522) of the inverting amplifier (520).

[0070] Meanwhile, noise may also be amplified by the inverting amplifier (520). Accordingly, a comparator (530) may be included in the anomaly detection unit (500) to distinguish between the output light signal output from the light emitting unit (100) and the noise. The input terminal (531) of the comparator (530) may be connected to the output terminal (522) of the inverting amplifier (520).

[0071] The comparator (530) can compare the input voltage with a reference value (or, reference), and output 0 if the input voltage is lower than the reference value, and output a set voltage (e.g., maximum voltage, power supply voltage) if the input voltage is higher. The reference value may be a value that is greater than noise and lower than the voltage output through the inverting amplifier (520) due to a high value of the output light signal output from the light emitting unit (100). In addition, the reference value may be determined by taking into consideration the rising time, the period of the signal output from the inverting amplifier (520), the voltage input to the VCSEL, etc. For example, since the rising time may vary depending on the magnitude of the voltage input to the VCSEL, the reference value may be determined by taking into consideration the voltage input to the VCSEL.

[0072] The comparator (530) can convert the waveform of the input voltage into a square wave. The comparator (530) can convert a signal with a long rising time into a square wave signal with a short rising time. A low reference value can shorten the rising time, but this can also lead to the problem that noise can also be viewed as a signal.

[0073] Fig. 6 illustrates an example of a circuit that constitutes a comparator, which may be a comparator (530) according to the present invention. The comparator (530) may be a Schmitt trigger, but the configuration of the comparator (530) according to the present invention is not limited thereto.

[0074] Referring to Fig. 6, the circuit constituting the comparator (530) may include an OP-AMP, a resistor, a power source, etc. In detail, the input terminal (531) of the comparator (530) may be connected to the (+) input terminal of the OP-AMP, and a reference value may be input to the (-) input terminal of the OP-AMP. In Fig. 6, the reference value is implemented through a circuit (533) composed of a plurality of resistors, but is not limited thereto. The output terminal of the OP-AMP may be the output terminal (532) of the comparator (530).

[0075] A level shifter (540) may be included when the output voltage of the comparator (530) is higher than the input voltage allowed in the next element connected to the comparator (530). An input terminal (541) of the level shifter (540) may be connected to an output terminal (532) of the comparator (530).

[0076] The level shifter (540) can adjust the output voltage of the comparator (530) according to the input voltage allowed by the element connected to the comparator (530). For example, if the output voltage of the comparator (530) is 5 V and the input voltage allowed by the next element connected to the comparator (530) is 3.3 V, the level shifter (540) can convert 5 V to 3.3 V.

[0077] Fig. 7 illustrates an example of a circuit that constitutes a level shifter, which may be a level shifter (540) according to the present invention. However, the configuration of the level shifter (540) according to the present invention is not limited thereto.

[0078] Referring to FIG. 7, the level shifter (540) may include an OP-AMP and a power supply. The input terminal of the OP-AMP may be an input terminal of the level shifter (540), and the output terminal of the OP-AMP may be an output terminal (542) of the level shifter (540). The output terminal (542) of the level shifter (540) may be connected to a control unit (400), and the control unit (400) may count an output signal of the level shifter (540).

[0079] As described above, the anomaly detection unit (500) can convert the output light signal output from the light emitting unit (100) into a square wave signal of a desired size to make it easy for the control unit (400) to count.

[0080] The anomaly detection unit (500) does not necessarily have to include all of the voltage divider (510), the inverting amplifier (520), the comparator (530), and the level shifter (540), and may include only the necessary components. For example, if the voltage of the output terminal of the comparator (530) is acceptable as the input voltage of the control unit (400), the level shifter (540) may be omitted. In addition, if the output voltage of the light emitting unit (100) is sufficiently low, the voltage divider (510) may be omitted. According to one embodiment, the anomaly detection unit (500) may be configured with only the comparator (530).

[0081] The control unit (400) can compare the number of counted square wave signals with the number of pulses set in the light emitting unit (100) to determine whether the light emitting unit (100) is operating normally. For example, the control unit (400) can specify the channel where the abnormality occurred, i.e., the anode, if the square wave signal is not counted at a specific time. If the control unit (400) determines that the light emitting unit (100) is not operating normally, the control unit (400) can stop the operation of the light emitting unit (100) or the corresponding anode of the light emitting unit (100). For example, if the control unit (400) determines that the light emitting unit (100) is not operating normally, the control unit (400) can cut off the power to the light emitting unit (100).

[0082] Depending on the voltage input to the anode of the VCSEL, some of the components included in the anomaly detection unit (500) may not operate, so the control unit (400) may first need to check whether the VCSEL is operating.

[0083] In the above, the anomaly detection unit (500) is described as a component of the lidar device (1000), but the lidar device (1000) may include an optical output device and an optical input device, and the optical output device may be configured to include a light emitting unit (100), an anomaly detection unit (500), and a control unit (400).

[0084] FIG. 8 is a diagram showing the results of simulating the voltage of the output terminal of each component included in the anomaly detection unit according to an embodiment of the present invention.

[0085] Specifically, in Fig. 8, the voltage at the voltage divider output terminal, the voltage at the inverting amplifier output terminal, the voltage at the comparator output terminal, and the voltage at the level shifter output terminal are displayed as simulation results.

[0086] Referring to Fig. 8, the voltage at the voltage divider output terminal is displayed as a negative value because it is lower than GND. An inverting amplifier can be used to convert the voltage at the voltage divider output terminal to a positive value, and a comparator can be used to reduce the rising time of the output voltage of the inverting amplifier and convert it into a square wave. If the magnitude of the comparator output voltage is outside the range allowed by the input voltage of the following configuration, a level shifter can be used to adjust the magnitude of the comparator output voltage.

[0087] Although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be construed as being included within the scope of the present invention defined in the appended claims.

Claims

1. VCSEL (Vertical Cavity Surface Emitting Laser); A comparator that generates a square wave by comparing the output of the cathode terminal of the VCSEL with a reference value; and An optical output device including a control unit that counts the output of the comparator to determine whether the VCSEL is abnormal.

2. In paragraph 1, An optical output device further comprising a voltage divider between the output terminal of the cathode of the VCSEL and the input terminal of the comparator.

3. In paragraph 2, An optical output device further comprising an inverting amplifier between the voltage divider and the comparator to invert the output of the voltage divider.

4. In paragraph 1, An optical output device further comprising a level shifter for adjusting the output size of the comparator between the comparator and the control unit.

5. In paragraph 1, An optical output device characterized in that the control unit cuts off power to the VCSEL when it is determined that there is an abnormality in the VCSEL.

6. In paragraph 1, An optical output device in which the control unit determines whether the VCSEL is abnormal by comparing the number of pulses transmitted through each anode of the VCSEL with the value calculated by the control unit from the output of the comparator.

7. In paragraph 1, An optical output device that determines whether the above VCSEL is abnormal by determining the channel in which the abnormality occurred.

8. In paragraph 1, An optical output device, characterized in that the reference value is determined based on the voltage input to the VCSEL.

9. Optical output device; and Includes an optical input device, The above optical output device, VCSEL; A comparator that generates a square wave by comparing the output of the cathode terminal of the VCSEL with a reference value; and A lidar device including a control unit that counts the output of the comparator to determine whether the VCSEL is abnormal.

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