Patent Publication Number: US-11390229-B2

Title: Optical output module, vehicle including same, and control method therefor

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of co-pending U.S. patent application Ser. No. 15/771,924 filed Apr. 27, 2018, which is the National Phase of PCT International Application No. PCT/KR2016/012232, filed on Oct. 28, 2016, which claims priority under 35 U.S.C. 119(a) to Patent Application Nos. 10-2015-0150575, filed in the Republic of Korea on Oct. 28, 2015 and 10-2016-0141697, filed in the Republic of Korea on Oct. 28, 2016, all of which are hereby expressly incorporated by reference into the present application. 
    
    
     TECHNICAL FIELD 
     Embodiments relate to an optical output module, a vehicle including the same, and a control method therefor. 
     BACKGROUND ART 
     A light detection and ranging (LiDAR) measuring apparatus transmits a beam toward an object and receives a reverse beam that is reflected and returned back by the objet to measure, examine, and analyze information on a distance or position of the object. 
       FIG. 1  is a diagram showing an outer appearance of a general optical output module  10 . 
     As shown in  FIG. 1 , the general optical output module  10  may emit a beam emitted from a plurality of light sources (not shown) toward an object in various directions using a motor (not shown) and receive a reverse beam using a detector. 
     In this case, a portion for emitting a plurality of beams  12  may be rotated (see arrow  20 ) by a motor and may be mechanically moved and, thus, there may be various limits. That is, it may not be easy to ensure mechanical reliability of a motor portion and, due to use of a motor, there may be a limit in reducing a size of the optical output module  10  and it may be difficult to ensure a scan rate of a specific region. In addition, there is a need for a plurality of light sources and detectors to extend a measurement range in a vertical direction. A light receiving unit for a general optical output module requires a condensing lens and, thus, efficiency is degraded and there is a limit in acquiring various pieces of information. 
     Recently, as interest in unmanned autonomous driving increases, an optical output module according to exemplary embodiments has been installed in a vehicle to realize unmanned autonomous driving of a vehicle. 
     First, unmanned autonomous driving is a technology for autonomously controlling steering, change of speed, acceleration, and braking according to a surrounding environment based on a recognition apparatus such as a sensor and a camera and an autonomous navigation apparatus such as a global positioning system (GPS) module to autonomously drive to a destination. 
     In addition, unmanned autonomous driving is a technology used in many fields such as a commercial field including an assistance device for the disabled as well as the non-disabled, for military purposes, and for cargo transport. 
     For unmanned autonomous driving of a vehicle on an actual road, a position, etc. of an obstacle positioned ahead or behind a driving vehicle need to be determined. 
     There is a problem in that an optical output module installed and used in a conventional vehicle is not capable of controlling a scan rate or is not capable of being appropriately driven according to a driving situation due to limitations of a driving method. For example, there is a problem in that, when a vehicle travels at high speed, distance resolution of a region of interest is remarkably degraded and resolution of position information, etc. of other vehicles positioned ahead is degraded. 
     DISCLOSURE 
     Technical Problem 
     Embodiments provide an optical output module and a vehicle for adjusting rotation speed of a detection direction in response to driving speed of a vehicle by a vehicle light detection and ranging (LiDAR) measuring apparatus for collecting surrounding information by a camera device installed in the vehicle during driving and measuring information on an object using a laser beam. 
     Further, embodiments provide an optical output module and a vehicle for effectively acquiring information according to state information of a driving situation, etc. of the vehicle. 
     Technical Solution 
     In one embodiment, an optical output module includes a driving controller and an optical transmitter configured to output light to scan the scan region, wherein the optical transmitter scans the scan region at at least one scan rate according to driving speed. 
     The scan region may include a high speed scan region and a low speed scan region, the high speed scan region may be positioned in a central portion of the scan region, and the low speed scan region may be a region obtained by excluding the high speed scan speed from the scan region. 
     The optical transmitter may scan the scan region at a first scan rate when scanning the high speed scan region and scan the scan region at a second scan rate when scanning the low speed scan region. 
     The first scan rate may be higher than the second scan rate. 
     The first scan rate may be equal to or greater than 15 Hz and the second scan rate may be 1 Hz to 10 Hz. 
     A center angle of the high speed scan region may be equal to or greater than at least 70°. 
     In another embodiment, a vehicle includes a body configured to provide a space with a user accommodated therein, and an optical output module disposed at a position adjacent to the body and configured to scan surrounding information of the body, wherein the optical output module includes, an optical transmitter configured to discharge a plurality of beams to a scan region and to scan the scan region, and an optical receiver configured to measure information on an object using a reverse beam via a process in which the discharged beam is reflected and returned back by the object positioned in the scan region, wherein the scan region includes at least one sub scan region, and wherein the optical transmitter scans the scan region at at least one scan rate according to driving speed of the body. 
     The scan region may include a high speed scan region and a low speed scan region, the high speed scan region may be positioned in a central portion of the scan region, and the low speed scan region may be a region obtained by excluding the high speed scan speed from the scan region. 
     The optical transmitter may scan the scan region at a first scan rate when scanning the high speed scan region and scan the scan region at a second scan rate when scanning the low speed scan region. 
     The first scan rate may be higher than the second scan rate. 
     In another embodiment, a method of controlling an autonomous driving vehicle including a light detection and ranging (LiDAR) measuring apparatus installed therein includes recognizing a rate of the vehicle, determining whether the rate of the vehicle is greater than a predetermined threshold rate, adjusting a scan rate when the rate of the vehicle is greater than the threshold value, and applying current to permit an optical output module in the LiDAR measuring apparatus to perform scanning at the adjusted scan rate. 
     The method may further include collecting information on the object using a reverse beam obtained by reflecting a beam discharged from the optical output module off an object positioned in a scan region. 
     The scan region may include at least one sub scan region, and the scan rate in the sub scan region may be adjusted by the rate of the vehicle. 
     The rate of the vehicle may be directly measured through the optical output module or may be provided from the vehicle. 
     In another embodiment, a light detection and ranging (LiDAR) measuring apparatus includes an optical transmitter configured to discharge a plurality of beams to a scan region to a scan region and to scan the scan region, and an optical receiver configured to measure information on an object using a reverse beam via a process in which the discharged beam is reflected and returned back by the object positioned in the scan region, wherein the scan region includes at least one sub scan region, and wherein the optical transmitter scans the at least one sub scan region at at least one scan rate. 
     Advantageous Effects 
     According to exemplary embodiments, an entire scan region or a scan available region of a vehicle light detection and ranging (LiDAR) measuring apparatus may be split into at least one sub scan region in response to driving speed of the vehicle with the vehicle LiDAR measuring apparatus installed therein and the at least one sub scan region may be scanned at different rates (different speeds), thereby enhancing scanning resolution with respect to a region of interest in response to driving speed of a vehicle with an optical output module installed therein. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram showing an outer appearance of a general light detection and ranging (LiDAR) module. 
         FIG. 2  is a block diagram of a LiDAR module according to an exemplary embodiment. 
         FIG. 3  is a block diagram of another exemplary embodiment of an optical receiver in an optical output module according to an exemplary embodiment. 
         FIG. 4  is a diagram showing an optical output module installed a vehicle to measure LiDAR according to an exemplary embodiment. 
         FIG. 5  is a diagram showing an optical output module installed a vehicle to measure LiDAR according to another exemplary embodiment optical output module. 
         FIG. 6  is a flowchart showing a method of controlling an optical output module installed in a vehicle depending on a rate of the vehicle according to an exemplary embodiment. 
     
    
    
     BEST MODE 
     The present disclosure will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the present disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. 
     The terms “first”, “second”, “on/upper/above”, and “under/lower/below” used herein are only used to distinguish one object or element from another object or element without requiring or including a physical or logical relationship or order between objects or elements. 
       FIG. 2  is a block diagram of a light detection and ranging (LiDAR) measuring apparatus according to an exemplary embodiment. 
     A LiDAR module illustrated in  FIG. 2  may include an optical transmitter  110 A, an optical receiver  120 A, a sensing unit  130 , and a driving controller  140 . 
     First, the optical transmitter  110 A may emit one or more beams or a plurality of beams. Although  FIG. 2  illustrates the case in which a plurality of beams is emitted according to the embodiment, one beam may be emitted. To this end, the optical transmitter  110 A may include a first heat sink  111 , at least one light source  112 , a transmission optical system  114 , and a beam steering unit  118 . The optical transmitter  110 A may further include a beam splitter  116 . 
     The at least one light source  112  may emit light. When a center wavelength of light emitted from the at least one light source  112  is greater than 2 μm, the light is light and, thus, may not be appropriate for light detection and ranging measurement. When a wavelength of light emitted from the at least one light source  112  is less than 0.2 μm, the light emitted from the optical transmitter  110 A may be harmful to humans and may also be absorbed by impurities in the air while proceeding toward an object (an object or a material) and, thus, may have difficulty in reaching a distant object. Accordingly, a center wavelength of light emitted from the at least one light source  112  may be 0.2 μm to 2 μm but exemplary embodiments are not limited thereto. 
     Here, the object may float in the air or may be positioned on the ground or may be a particle that floats in the air. Exemplary embodiments are not limited to a specific type of object. 
     Wavelength distribution of the at least one light source  112  may be equal to or less than 1 μm. 
     The at least one light source  112  may be a pulse type light source with a predetermined duty rate. On time of a pulse may be equal to or greater than 1 nm. A pulse type may be square wave, a triangular wave, a sawtooth wave, a sine wave, a delta function, or a sine function (sinc function). In addition, a pulse period may not be constant. 
     The at least one light source  112  may be a light source device with one or more space modes. In this case, the space mode may be represented by ‘n’ order of a Gaussian or Lambertian space mode, where n is equal to or greater than 1. 
     The at least one light source  112  may be a light source device represented by the sum of linear polarization or circular polarization. In this case, a ratio of polarization components may be represented as 1:A based on one polarization component and A may be equal to or less than 1. 
     Although  FIG. 2  illustrates only one light source  112 , exemplary embodiments are not limited thereto. According to another exemplary embodiment, the number of the light sources  112  may be plural. When the at least one light source  112  includes a plurality of light sources, types of the plurality of light sources may be the same or different. 
     Heat generated from the at least one light source  112  may adversely affect an operation of the optical output module. Accordingly, the first heat sink  111  may dissipate heat generated from the at least one light source  112 . As necessary, the first heat sink  111  may be omitted. 
     The beam splitter  114  may split light emitted from the at least one light source  112  into a first beam B 1  and a second beam B 2 . The first beam B 1  split by the beam splitter  114  may be dissipated toward the split first beam B 1  and the second beam B 2  may be discharged toward the beam steering unit  118 . 
     An intensity ratio between the first beam B 1  and the second beam B 2  of the light split by the beam splitter  114  may be K:1. For example, K may be greater than 0 and less than 10. 
     The beam splitter  114  may include a device using at least one method selected from linear polarization, circular polarization, a space mode of the light source  112 , or a wavelength of the light source  112 . 
     The beam splitter  114  may include at least one of a device for spatially splitting light or a device for temporally splitting light. The beam splitter  114  may be omitted. 
     The transmission optical system  114  may be disposed between the at least one light source  112  and the beam splitter  116  and, when the beam splitter  114  is omitted, the transmission optical system  114  may be disposed between a light source and the beam steering unit  118 . The transmission optical system  114  may include a collimator  114 A for collimating light emitted from the at least one light source  112 . As necessary, the transmission optical system  114  may be omitted. 
     The beam steering unit  118  may split the second beam B 2  emitted from the beam splitter  116  into a plurality of third beams B 3  [B 0 , B(1−1), . . . B(1−N), B(2−1), . . . B(2−M)] and emit the third beams B 3  in different directions. Here, N may be a positive integer equal to or greater than 1 and M may be a positive integer equal to or greater than 1. The third beams B 3  will be described below in detail. When the beam splitter  116  is omitted, the beam steering unit  118  may steer one beam. 
     According to the exemplary embodiment, the beam steering unit  118  may include at least one transmission optical device. Although  FIG. 2  illustrates the case in which the beam steering unit  118  includes first and second transmission optical devices S 1  and S 2 , exemplary embodiments are not limited thereto. That is, the beam steering unit  118  may include only one transmission optical device or two or more transmission optical devices. Hereinafter, although the case in which the beam steering unit  118  includes the first and second transmission optical devices S 1  and S 2  will be described, exemplary embodiments are not limited thereto. 
     The first and second transmission optical devices S 1  and S 2  may split the second beam B 2  emitted from the beam splitter  116  into the plurality of third beams B 3  and emit the third beams B 3  in different directions. When the beam splitter  116  is omitted, the first and second transmission optical devices S 1  and S 2  may receive and steer a single beam. 
     A plurality of beams emitted toward an object from the optical transmitter  110 A may include the first beam B 1  and the third beam B 3 . Each of the first and second transmission optical devices S 1  and S 2  may emit the plurality of beams B 1  and B 3  toward an object in different directions without being mechanically rotated by a motor or the like. 
     The first and second transmission optical devices S 1  and S 2  may include at least one lens. In this case, at least some lens S 1  included in the transmission optical device may be driven and, to drive the some lens S 1 , a beam emitted from the beam steering unit  118  may be steered. 
     Each of the first and second transmission optical devices S 1  and S 2  may split the second beam B 2  into the plurality of third beams B 3  in different directions and emit the third beams B 3  in response to at least one of an electrical signal, a physical signal, or a chemical signal. The electrical signal, the physical signal, or the chemical signal may be provided from the driving controller  140  to the optical transmitter  110 A in the form of a first control signal C 1 . That is, an external stimulus may be present, at least one of the electrical signal, the physical signal, or the chemical signal may be generated as the first control signal C 1  from the driving controller  140  by the stimulus, and a traveling path (i.e., an emission angle) of the plurality of third beams B 3  emitted from each of the first and second transmission optical devices S 1  and S 2  may be determined according to the generated first control signal C 1 . 
     Each of the first and second transmission optical devices S 1  and S 2  may be embodied as a transmission optical phased array (OPA). The transmission OPA may generate the plurality of third beams B 3  to be emitted in different directions from the second beam B 2  split by the beam splitter  116 . 
     Each of the first and second transmission optical devices S 1  and S 2  embodied as a transmission OPA may be embodied in various following methods. 
     First, each of the first and second transmission optical devices S 1  and S 2  may have a surface on which a diffraction grating is periodically formed. In this case, when at least one of a grating period, angle, or shape is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     The first and second transmission optical devices S 1  and S 2  may have respective internal structures with a periodically changed refractive index difference. In this case, when a period is changed or a refractive index is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have a polarization grating structure for periodic on/off of polarization using liquid crystal. In this case, when at least one of an interval or transmittance of a grating is adjusted, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may be configured in the form of a double refraction prism. In this case, when an angle of a prism is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have a structure with a boundary surface between air and liquid such as oil. In this case, when a signal is externally applied to change the boundary surface or a refractive index of liquid is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     When a refractive index or density distribution pattern in a medium is changed using a hologram method, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have a structure with transmittance that is periodically changed depending on intensity of liquid crystal. In this case, when a period is changed or transmittance is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have a microelectromechanical system (MEMS) mirror array. In this case, when an operation state of each pixel is controlled, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     When an ultrasonic wave is injected into a medium and a frequency of the ultrasonic wave is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have a medium in which an electric field is formed in up, down, right, and left directions. In this case, when the intensity and frequency of an electric field is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have two or more aligned lens sets. In this case, when a separate lens of the lens set is moved in up, down, right, and left directions, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have two or more aligned microlens array (MLA) sets. In this case, when a separate MLA is moved in up, down, right, and left directions, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     Each of the first and second transmission optical devices S 1  and S 2  may have two or more aligned microlens array (MLA) sets. In this case, when the period or shape of a separate MLA is changed, the first and second transmission optical devices S 1  and S 2  may generate the plurality of third beams B 3  to be emitted in different directions. 
     To permit the aforementioned various transmission optical devices to emit light in different directions, a width range within which the aforementioned period (or a pattern such as a surface) is changed may be 0.1 μm to 2 μm, in the case of a wavelength of 1000 nm, a range within which the aforementioned refractive index is changed may be greater than 1 and less than 2.7, and a range within which the aforementioned transmittance and reflectivity are changed may be greater than 0 and less than 1 but exemplary embodiments are not limited thereto. 
     The aforementioned various transmission optical devices may be complexly combined and may generate the plurality of third beams B 3  to be emitted in different directions. 
     To operate each of the first and second transmission optical devices S 1  and S 2  with the aforementioned various structures, an electrical signal may be applied to opposite ends of each of the first and second transmission optical devices S 1  and S 2 . In this case, the electrical signal may be a periodic voltage signal or a current signal. For example, an operational frequency of the electrical signal may be equal to or less than 10 GHz. 
     To operate each of the first and second transmission optical devices S 1  and S 2  with the aforementioned various structures, physical pressure may be applied to the first and second transmission optical devices S 1  and S 2  or a physical position of the first and second transmission optical devices S 1  and S 2  may be changed. In this case, the physical position of the first and second transmission optical devices S 1  and S 2  may be moved in an optical axis direction or moved along two axes perpendicular to the optical axis direction. To this end, a magnetic field may be used, a piezoelectric (PZT) device may be used, a voice coil motor (VCM) may be used, a link structure may be used, or gravity and elasticity may be used. 
     The plurality of third beams B 3  emitted from the first and second transmission optical devices S 1  and S 2 , which embody the beam steering unit  118 , may include at least one of a 0th beam BO emitted in an optical axis direction, N(1−1)th to (1−N)th beams B(1−1), . . . B(1−N) emitted to be spaced apart from each other counterclockwise from the optical axis direction, or M(2−1)th to (2−M)th beams B(2−1), . . . B(2−M) emitted to be spaced apart from each other clockwise from the optical axis direction. 
     The plurality of third beams B 3  B 0 , B(1−1), . . . B(1−N), B(2−1), . . . B(2−M) may be emitted to be spaced apart from each other. The (1−1)th to (1−N)th beams B(1−1), . . . B(1−N) and (2−1)th to (2−M)th beams B(2−1), . . . B(2−M) may be emitted to be spaced apart from each other at a predetermined angle with the 0th beam BO. For example, the (1−1)th beam B(1−1) may be spaced apart from the 0th beam BO at a (1−1)th angle θ(1−1)T, the (1−N)th beam B(1−N) may be spaced apart from the 0th beam BO at a (1−N)th angle θ(1−N)T, the (2−1)th beam B(2−1) may be spaced apart from the 0th beam BO at a (2−1)th angle θ(2−1)T, and the (2−M)th beam B(2−M) may be spaced apart from the 0th beam BO at an (2−M) angle θ(2−M)T. 
     Among angles at which the plurality of third beams B 3  are spaced apart from each other, the (1−N)th or (2−M)th beams B(1−N) and B(2−M) may be spaced apart from the 0th beam BO by the largest angle. The largest angle θ(1−N)T or θ(2−M)T may be less than 90° but exemplary embodiments are not limited thereto. 
     An angle at which neighboring beams are spaced apart from each other among 0th, (1−1)th to (1−N)th and (2−1)th to (2−M)th beams BO, B(1−1), . . . B(1−N), B(2−1), . . . B(2−M) may be less than 200 but exemplary embodiments are not limited thereto. 
     The optical receiver  120 A may receive a plurality of reverse beams, obtained via a process in which one beam or the plurality of beams B 1  and B 3  emitted from the optical transmitter  110 A are reflected by an object (not shown), at different angles and, measure (examine or analyze) information on the object using the plurality of received reverse beams. 
     According to the exemplary embodiment, the optical receiver  120 A may include a second heat sink  121 , an optical inspector  122 , an optical detector  124 , a filter  126 A, and a reception optical system  128 . The optical detector  124  may be omitted from the optical receiver  120 A. 
     The optical detector  124  may receive a plurality of reverse beams RBs, which are reflected and returned back by an object, at different angles and transmit the reverse beams RBs to the optical inspector  122  at a predetermined angle. 
     The reverse beams RBs incident on the optical detector  124  may include at least one of a 0th reverse beam RO that is incident in an optical axis direction, i(1−1)th to (1−i)th reverse beams R(1−1), . . . R(1−i) that are spaced apart from each other counterclockwise from an optical axis direction and are incident on, or j(2−1)th to (2−j)th reverse beams R(2−1), . . . R(2−j) that are spaced apart clockwise from the optical axis direction and are incident. Here, i may be a positive integer equal to or greater than 1 and j may be a positive integer equal to or greater than 1. 
     Each of the (1−1)th to (1−i)th reverse beams R(1−1), . . . R(1−i) and the (2−1)th to (2−j)th reverse beams R(2−1), . . . R(2−j) may be spaced apart from a 0th reverse beam RO at a predetermined angle. For example, the (1−1)th reverse beam R(1−1) may be spaced apart from the 0th reverse beam RO at a (1−1)th angle θ(1−1)R, the (1−i)th reverse beam R(1−i) may be spaced apart from the 0th reverse beam RO at the (1−i)th angle θ(1−i)R, the (2−1)th reverse beam R(2−1)th may be spaced apart from the 0th reverse beam RO at the (2−1)th angle θ(2−1)R, and the (2−j)th reverse beam R(2−j) may be spaced apart from the 0th reverse beam RO at the (2−j)th θ(2−j)R. As such, the plurality of reverse beams R 0 , R(1−1), . . . R(1−i), R(2−1), . . . R(2−j) may be spaced apart from each other and may be incident on the optical detector  124 . 
     The optical detector  124  may include at least one reception optical device. Although  FIG. 2  illustrates the case in which the optical detector  124  includes first and second reception optical devices D 1  and D 2 , exemplary embodiments are not limited thereto. That is, according to other exemplary embodiments, the optical detector  124  may include only one reception optical device or may include three or more reception optical devices. Like the transmission optical devices S 1  and S 2 , the reception optical devices D 1  and D 2  may be operated in response to at least one of an electrical signal, a physical signal, or a chemical signal. The electrical signal, the physical signal, or the chemical signal may be provided from the driving controller  140  to the optical receiver  120 A in the form of a second control signal C 2 . That is, an external stimulus may be present, at least one of the electrical signal, the physical signal, or the chemical signal may be generated as the second control signal C 2  from the driving controller  140  by the stimulus, and each of the first and second reception optical devices D 1  and D 2  may adjust at least one of transmittance or reflectivity by the generated second control signal C 2 . 
     Each of the first and second reception optical devices D 1  and D 2  may be embodied as a reception OPA. The reception OPA may emit a plurality of reverse beams at different angles to output the beams at a constant angle. Each of the first and second reception optical devices D 1  and D 2  embodied as a reception OPA may be operated using various following methods. 
     First, each of the first and second reception optical devices D 1  and D 2  may have a surface on which a diffraction grating is periodically formed. In this case, when at least one of a grating period, angle, or shape is changed, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     The first and second transmission optical devices S 1  and S 2  may have respective structures with a periodically changed refractive index difference. In this case, when a period is changed or a refractive index is changed, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     Each of the first and second reception optical devices D 1  and D 2  may have a double refraction prism. In this case, when an angle of the prism is changed, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     Each of the first and second reception optical devices D 1  and D 2  may have a structure with a boundary surface between air and liquid such as oil. In this case, when a signal is externally applied to change the boundary surface or a refractive index of liquid is changed, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     When a refractive index or density distribution pattern in a medium is changed using a hologram method, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     Each of the first and second reception optical devices D 1  and D 2  may have two or more lens sets. In this case, when a separate lens of the lens set is moved in up, down, right, and left directions, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     Each of the first and second reception optical devices D 1  and D 2  may have two or more aligned microlens array (MLA) sets. In this case, when a separate MLA is moved in up, down, right, and left directions, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     Each of the first and second reception optical devices D 1  and D 2  may have two or more aligned microlens array (MLA) sets. In this case, when at least one of the period or shape of a separate MLA is changed, each of the first and second reception optical devices D 1  and D 2  may be operated. 
     To operate the aforementioned various reception optical devices, a width range within which the aforementioned period (or a pattern such as a surface) is changed may be 0.1 μm to 2 mm, in the case of a wavelength of 1000 nm, a range within which the aforementioned refractive index is changed may be greater than 1 and less than 2.7, and a range within which the aforementioned transmittance and reflectivity are changed may be greater than 0 and less than 1 but exemplary embodiments are not limited thereto. 
     The optical detector  124  may multiply include the reception optical device that is operated in various ways as described above. 
     To operate the first and second reception optical devices D 1  and D 2  with various structures as described above, an electrical signal may be applied to opposite ends of each of the first and second reception optical devices D 1  and D 2 . In this case, the electrical signal may be a periodic voltage signal or current signal. For example, an operation rate of the electrical signal may be equal to or less than 10 GHz. 
     To operate the first and second reception optical devices D 1  and D 2  with various structures as described above, physical pressure may be applied to the first and second reception optical devices D 1  and D 2  and a physical position of the first and second reception optical devices D 1  and D 2  may be changed. In this case, the physical position of the first and second reception optical devices D 1  and D 2  may be moved in an optical axis direction or moved in two-axis directions perpendicular to the optical axis direction. To this end, a magnetic field may be used, a piezoelectric (PZT) device may be used, a voice coil motor (VCM) may be used, a link structure may be used, or gravity and elasticity may be used. 
     An angle at which a reverse beam is incident may be adjusted using various methods. For example, the (1−i)th or (2−j)th reverse beams R(1−i) and R(2−j) may be spaced apart from the 0th beam BO by the largest angle. The largest angle θ(1−i)R or θ(2−j)R may be less than 90° but exemplary embodiments are not limited thereto. 
     An angle between adjacent beams among 0th, (1−1)th to (1−i)th and (2−1)th to (2−j)th beams RO, R(1−1), . . . R(1−i), R(2−1), . . . R(2−j) may be set to be less than 20° but exemplary embodiments are not limited thereto. 
     The reception optical system  128  may be disposed between the optical inspector  122  and the optical detector  124  and may focus light emitted from the optical detector  124  to provide the light to the optical inspector  122 . To this end, the reception optical system  128  may include a collector  128 A but exemplary embodiments are not limited thereto. As necessary, the reception optical system  128  may be omitted. 
       FIG. 3  is a block diagram of another exemplary embodiment  120 B of an optical receiver in an optical output module according to an exemplary embodiment. 
     An optical receiver  120 B illustrated in  FIG. 3  may include the second heat sink  121 , the optical inspector  122 , the optical detector  124 , a filter  126 B, and the reception optical system  128 . Except that the form of the filter  126 B is different from the filter  126 A illustrated in  FIG. 2 , the optical receiver  120 B illustrated in  FIG. 3  may be the same as the optical receiver  120 A illustrated in  FIG. 2 . 
     The filters  126 A and  126 B may be disposed between the optical detector  124  and the reception optical system  128 , may selectively filter at least one wavelength required by a reverse beam emitted from the optical detector  124  or remove noise, and may pass or reflect and provide the result to the optical inspector  122 . The transmissive filter  126 A shown in  FIG. 2  may selectively pass and filter a desired wavelength and, on the other hand, the reflective filter  126 A shown in  FIG. 3  may selectively reflect and filter a desired wavelength. 
     As necessary, the filters  126 A and  126 B may be omitted. 
     A reception OPA outputs reverse beams that are incident at different angles, at a constant angle and, thus, the transmission or reflection efficiency of the filters  126 A and  126 B may be enhanced. 
     A wavelength range filtered by the filters  126 A and  126 B may be one or plural. 
     A range of a center wavelength of at least one wavelength filtered by the filters  126 A and  126 B may be 0.2 μm to 2 μm and a bandwidth of a filtered wavelength may be 1 nm or greater. When a ratio of intensity of a wavelength interrupted by the filters  126 A and  126 B and intensity of a selected wavelength is F:1, F may be equal to or less than 0.5. 
     A filter optical device having at least one central angle of incident light with maximum transmission efficiency of the filter  126 A or maximum reflection efficiency of the filter  126 B may be included. Here, the filter optical device may be embodied in various forms. 
     For example, filter optical devices  126 - 1  and  126 - 2  may be configured in such a way that two or more thin films with two or more refractive indexes are stacked. In addition, the filter optical device may be embodied in such a way that a grating structure is formed on a surface of the filter optical device to adjust a refractive or reflective angle of a specific wavelength. Alternatively, the filter optical device may be configured to select a specific wavelength by periodically changing an internal refractive index. 
     Light with a wavelength selected by the filters  126 A and  126 B may be passed or reflected and transmitted to the optical inspector  122 . In this case, when the filter  126 A is a transmissive filter for passing light and transmitting the light to the optical inspector  122 , if an incident angle of light incident on the transmissive filter  126 A is equal to or less than 60°, transmission efficiency of the filter  126 A may be maximized. In addition, when the filter  126 B is a reflective filter for reflecting light and transmitting the light to the optical inspector  122 , if an angle of light incident on the reflective filter  126 B is equal to or greater than 25°, reflection efficiency of the filter  126 B may be maximized. 
     The second heat sink  121  may dissipate heat emitted from the optical inspector  122  and, as necessary, may be omitted. 
     The optical inspector  122  may measure (or analyze) information on an object from a reverse beam that is provided through the filters  126 A and  126 B from the optical detector  124 . 
     The optical inspector  122  may measure a time difference between a plurality of beams emitted from the optical transmitter  110 A and a reverse beam output from the optical detector  124 . To this end, intensity of a reverse beam, obtained via a process in which a plurality of beams B 1  and B 3  emitted from the optical transmitter  110 A is reflected and returned back by an object, may be converted into an electrical signal. In addition, intensity of a reverse beam, obtained via a process in which the plurality of beams B 1  and B 3  emitted from the optical transmitter  110 A is reflected by the object, may be converted into an electrical signal in a time sequence. In this case, the optical inspector  122  may measure a time difference between a plurality of beams and a reverse beam using the electrical signal. 
     The optical inspector  122  may measure a time difference based on a time point when some of light emitted from the optical transmitter  110 A is first measured. In addition, the optical inspector  122  may measure a time difference based on an electrical signal synchronized with the optical transmitter  110 A. 
     One or plural light receiving units are arranged in the form of a one-dimensional or two-dimensional array to embody the optical inspector  122 . In this case, a time difference of light reflected at a predetermined position may be measured using a plurality of light receiving units. Alternatively, a spatial difference of signals or a time difference between spaces may be measured through a plurality of light receiving units. In this case, a received signal for each pixel of an array may be distinguished and converted into an electrical signal. For example, the light receiving unit may use an avalanche photodiode (APD), a single photon avalanche photodiode (SPAPD), a single avalanche photodiode (SAPD), a photodiode (PD), a quantum well photodiode (QWP), a photo multiplying tube (PMT), or the like. 
     The optical inspector  122  may simultaneously measure a time difference and a spatial position between reverse obtained via a process in which light transmitted from the optical transmitter  110 A is reflected and returned back by an object. 
     The optical inspector  122  may analyze information on an object using at least one of intensity of a reverse beam or a spatial position of the object. Here, information on the inspected object may include, for example, at least one of distance or position information of the object. 
     The optical inspector  122  may measure basic data for measuring information on an object and transmit the measurement result to an analysis unit (not shown). In this case, the analysis unit may analyze information on the object using the basic data measured by the optical inspector  122 . 
     The aforementioned optical output module according to an exemplary embodiment may further include a first housing H 1 . The first housing H 1  may be shaped to surround the optical transmitter  110 A and the optical receiver  120 A. However, the first housing H 1  may be omitted. 
     The driving controller  140  may control at least one of the optical transmitter  110 A or the optical receiver  120 A. That is, the driving controller  140  may generate an electrical signal, a physical signal, or a chemical signal in the form of the first and second control signals C 1  and C 2  and control driving of the transmission optical devices S 1  and  32  and the reception optical devices D 1  and D 2  according to the first and second control signals C 1  and C 2 . 
     Here, each of the first and second control signals C 1  and C 2  generated by the driving controller  140  may take the form of a continued wave (CW) or a continued pulse and exemplary embodiments are not limited to a specific form of the first and second control signals C 1  and C 2 . 
     The sensing unit  130  may sense the first beam B 1  split by the beam splitter  116  and transmit the sensing result to the driving controller  140 . In this case, the driving controller  140  may generate the first and second control signals C 1  and C 2  using the sensing result received from the sensing unit  130  and control the optical transmitter  110 A and the optical receiver  120 A using the generated first and second control signals C 1  and C 2 . 
     For the aforementioned operation, the sensing unit  130  may include a photodiode  132  and a sensing optical system  134 . The photodiode  132  may sense the first beam B 1  split by the beam splitter  116 , convert the first beam B 1  into an electrical signal, and output the converted electrical signal as the sensing result to the driving controller  140 . 
     The sensing optical system  134  may be arranged between the split first beam B 1  and the photodiode  132 . To this end, the sensing optical system  134  may include, for example, a plurality of prisms  134 - 1  and  134 - 2  but exemplary embodiments are not limited thereto. 
     As described above, the optical transmitter  110 A and the optical receiver  120 A may be controlled using the first beam B 1  split by the beam splitter  116  and, thus, the accuracy of a value that is lastly inspected by the optical inspector  122  may be enhanced. For example, as an analysis result of the sensing result of the sensing unit  130 , when intensity of the first beam B 1  is determined to be weak, intensity of the second beam B 2  may be estimated to be weak. Accordingly, to increase intensity of the second beam B 2 , the driving controller  140  may increase intensity of light emitted from the light source  112  by a desired degree. Accordingly, intensity of the plurality of beams B 1  and B 3  is weak and, thus, intensity of a plurality of reverse beams received by the optical receiver  120 A and  120 B is weak, thereby overcoming a problem in that information on an object is not capable of being accurately analyzed. 
     The aforementioned optical output module according to an exemplary embodiment may further include a second housing H 2 . The second housing H 2  may be shaped to surround the sensing unit  130 . However, the second housing H 2  may be omitted. 
     According to an exemplary embodiment, a plurality of beams emitted to an object may include the first beam B 1  as well as the third beam B 3 . Accordingly, a direction of a beam emitted to an object may be extended compared with a conventional case. Such extension of a direction of a beam is described below with reference to the accompanying drawings. 
     Recently, as interest in unmanned autonomous driving increases, an optical output module according to exemplary embodiments has been installed in a vehicle to realize unmanned autonomous driving of a vehicle. 
     First, unmanned autonomous driving is a technology for autonomously controlling steering, change of speed, acceleration, and braking according to a road environment based on an obstacle recognition apparatus such as a sensor and a camera and an autonomous navigation apparatus such as a global positioning system (GPS) module to autonomously drive to a destination without a driver. 
     Unmanned autonomous driving is a technology used in many fields such as a commercial field including an assistance device for the disabled as well as the non-disabled, for military purposes, and for cargo transport. 
     For unmanned autonomous driving of a vehicle on an actual road, a position of another vehicle positioned ahead or behind a driving vehicle and surrounding information including an obstacle, etc. need to be recognized and determined. 
     An optical output module installed and used in a conventional vehicle does not consider a scan rate according to a vehicle driving situation. For example, when a vehicle travels at high speed, if the vehicle has the same scan rate as in the case in which the vehicle travels at low speed, an optical output module installed in the vehicle is moved therewith in response to driving speed and, thus, there is a problem in that distance resolution is remarkably reduced, degrading resolution of surrounding information of an obstacle or a position of another vehicle positioned ahead or behind the vehicle. 
     Exemplary embodiments may provide an optical output module for overcoming the aforementioned problem, which is described below in detail with reference to  FIGS. 4 and 5 . 
     With regard to configuration of light detection and ranging (LiDAR), an apparatus that is selectively driven at the same frame rate or at a variable rate according to a region of interest during 1D (line) or 2D (horizontal/vertical) output is described in detail. 
       FIG. 4  is a diagram showing an optical output module installed in a vehicle to measure LiDAR according to an exemplary embodiment.  FIG. 5  is a diagram showing an optical output module installed a vehicle to measure LiDAR according to another exemplary embodiment optical output module. 
       FIG. 4  illustrates an optical output module when a vehicle travels at low speed according to an exemplary embodiment. When the optical output module according to the exemplary embodiment scans a front side of the vehicle at a first scan rate A when the vehicle travels at low speed and scans a region in which a center angle based on a center of the vehicle has a first scan angle θ 1 . 
     Here, a scan rate of a specific region detected by a LiDAR measuring apparatus for a vehicle may be a time period in which a beam output from an optical output module stays in the specific region or a frequency of scanning the specific region. 
     The first scan rate A may be a rate with sufficient resolution when a vehicle travels at a threshold value (VC) or less while travelling at low speed. 
     For example, the first scan rate A may be 1 Hz to 35 Hz and may be configured to have the same value in a range of the first scan angle θ 1 . 
     The first scan angle θ 1  may be an angle at which a vehicle is capable of recognizing another vehicle that travels ahead or behind the vehicle. 
     For example, the first scan angle θ 1  may be 70° or greater. 
       FIG. 5  is a diagram showing an optical output module when a vehicle travels at high speed according to an exemplary embodiment. When the vehicle travels at a threshold rate (VC) or greater while traveling at high speed, a higher scan rate than the first scan rate A as a scan rate in the aforementioned case in which the vehicle travels at low speed may be provided. 
     The optical output module may collect information on an object using a plurality of reverse beams obtained via a process in which light emitted from an optical transmitter is reflected and returned back by an object and, in this regard, there is a problem in that it is not possible to scan the first scan angle θ 1  for scanning in the case in which the vehicle travels at high speed equal to or greater than the threshold rate (VC), at a higher scan rate (e.g., higher speed). 
     Accordingly, to prevent resolution from being degraded, when a vehicle travels at high speed, it may be necessary to operate the vehicle at a high scan rate different from the case in which the vehicle travels at low speed. However, a range of a scan rate for operating a vehicle LiDAR measuring apparatus may be limited and a scan rate may be increased in response to driving speed of the vehicle but there may be a limit in increasing a scan rate in all regions. Accordingly, the vehicle LiDAR measuring apparatus may selectively collect surrounding information for each surrounding region of the vehicle in response to surrounding speed of the vehicle. 
     In particular, when a vehicle travels at high speed, information to be received from a front side may be more important than a lateral side of the vehicle compared with the case in which the vehicle travels at low speed. Accordingly, as a scan rate for collecting front information based on a driving direction of the vehicle in a vehicle that travels at high speed is increased, vehicle running stability based on information collected through a vehicle LiDAR measuring apparatus may be enhanced. 
     A scan angle of the optical output module according to an exemplary embodiment may be the first scan angle θ 1  like in the case in which a vehicle travels at low speed. 
     The first scan angle θ 1  may include a second scan angle θ 2  as a center angle of a region to be scanned at a high scan rate and a third scan angle θ 3  as a center angle to be scanned at a low scan rate. 
     One or two or more third scan angles  93  may be present. 
     In other words, a center angle of a high speed scan region in which high speed scan is performed at a high scan rate may be the second scan angle θ 2  and a center angle of a low speed scan region in which low speed scan is performed at a relatively low speed may be one or two or more third scan angles θ 3 . 
     The high speed scan region may be positioned at a central portion of an entire scan region and the low speed scan region may be positioned at opposite sides except for the high speed scan region in the entire scan region. However, this is merely an exemplary embodiment, the exemplary embodiment is not limited thereto, and low and high speed scan regions may be set in different forms. 
     That is, the sum of a second scan region as a high speed scan region and a third scan region as a low speed scan region may be the same as an entire scan region, a central angle of which is the first scan angle θ 1 . 
     Exemplary embodiments are not limited to the case in which a low scan region is positioned at opposite sides, when a region of interest is generated, the generated region of interest may be set to a high speed scan region and driven at a high scan rate, and a portion except for the region of interest may be set to a low speed scan region and driven at a lower scan rate than the high speed scan region. 
     The optical output module according to an exemplary embodiment may perform scanning at a second scan rate B in a high speed scan region and perform scanning at a third scan rate C in a low sped scan region. 
     That is, the second scan rate for scanning the high speed scan region and the third scan rate for scanning the low speed scan region may be different. 
     For example, the second scan rate B may be equal to or greater than 20 Hz. 
     The third scan rate C may be used to scan a low speed scan region and, thus, may be less than the second scan rate B. 
     For example, the third scan rate C may be 1 Hz to 10 Hz. 
     However, the second scan rate B and the third scan rate C are an example for convenience of description and may be changed in various ways as necessary and, a scope of the present disclosure is not limited as long as the second scan rate B is greater than the third scan rate C. 
     Hereinafter, a method of controlling an optical output module depending on a rate of a vehicle during vehicle driving according to an exemplary embodiment is described. 
       FIG. 6  is a flowchart showing a method of controlling an optical output module installed in a vehicle depending on a rate of the vehicle according to an exemplary embodiment. 
     Referring to  FIG. 6 , first, the optical output module according to an exemplary embodiment may measure a rate of a vehicle in which the optical output module is installed (Sl 00 ). 
     Vehicle driving speed (rate) may be measured using various devices and this would be obvious to one of ordinary skill in the art and, thus, the method and configuration of measuring a vehicle rate are not described. For example, a vehicle LiDAR measuring apparatus may directly detect driving speed of the vehicle and receive the driving speed of the vehicle from a vehicle in which the vehicle LiDAR measuring apparatus is installed. 
     A vehicle rate is measured (S 100 ) and, then, whether the vehicle rate is greater than a current rate VC may be determined (S 200 ). 
     When the current rate of the vehicle is greater than the threshold rate VC, current driving may be determined as high speed driving and the scan rate may be corrected (S 300 ), and current may be applied to an actuator, for example, the beam steering unit  118  (S 400 ). 
     That is, as described, when a vehicle travels at high speed, an entire scan region may be divided into a high speed scan region and a low speed scan region and may be changed to provide rapid response with respect to a region of interest (i.e., a surrounding region that becomes important in response to vehicle driving speed). 
     When the current rate of the vehicle is less than the threshold rate (VC), the current driving may be determined as low speed driving and an entire scan region may be scanned at a constant rate without correction of a scan rate. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.