Patent Publication Number: US-10775484-B2

Title: Lidar apparatus for vehicles and vehicle having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of an earlier filing date and right of priority to Korean Patent Application No. 10-2016-0070679, filed on Jun. 8, 2016 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure generally relates to a light detection and ranging apparatus for vehicles and a vehicle having the same. 
     BACKGROUND 
     A vehicle is an apparatus that transports people or materials in a direction that is desired by a user. A common example of a vehicle is an automobile. 
     Vehicles typically implement a variety of sensors and electronic devices designed to improve the convenience of users of the vehicles. As an example, some vehicles implement an Advanced Driver Assistance System (ADAS) that utilizes data from sensors and other electronic devices to assist drivers. In addition, autonomous vehicles have been actively developed, which are designed to autonomously perform one or more driving operations of the vehicle. 
     Vehicles, such as those implementing ADAS and those that are autonomous vehicles, typically utilize various kinds of sensors, which include a radar, a light detection and ranging (lidar) apparatus, and/or a camera. 
     In particular, a lidar apparatus is a sensor that measures distances to objects by transmitting light towards an object and detecting properties of light reflected from the object. 
     SUMMARY 
     Implementations described herein provide a lidar apparatus for a vehicle that is configured to perform adaptive beam steering by adjusting an angle of transmission light based on a driving state of the vehicle. 
     In one aspect, a light detection and ranging (lidar) apparatus for a vehicle may include: a transmission unit configured to output transmission light; a reception unit configured to receive reflection light that results from the transmission light being reflected by an object; and at least one processor. The at least one processor may be configured to: based on a driving state of the vehicle, adjust an angle of beam steering of the transmission light. 
     In some implementations, the lidar apparatus may further include an interface unit. The at least one processor may be further configured to receive information regarding the driving state of the vehicle through the interface unit. 
     In some implementations, the information regarding the driving state of the vehicle may include at least one of first information sensed in the vehicle or second information sensed outside the vehicle. 
     In some implementations, the first information sensed in the vehicle may include at least one of: vehicle attitude information, vehicle driving direction information, vehicle location information, vehicle angle information, vehicle speed information, vehicle acceleration information, vehicle tilt information, vehicle forward/reverse movement information, steering-wheel rotation angle information, information regarding a pressure applied to an accelerator pedal, or information regarding a pressure applied to a brake pedal. 
     In some implementations, the second information sensed outside the vehicle may include information regarding an object located outside the vehicle. The object located outside the vehicle may include at least one of a lane in a road, another vehicle, a pedestrian, a light, a traffic signal, a road, a structure, a bump, a geographical feature, or an animal. 
     In some implementations, the at least one processor may be further configured to generate the information regarding the object based on the reflection light that is received by the reception unit. 
     In some implementations, the information regarding the driving state of the vehicle may include information regarding an object located around the vehicle. 
     In some implementations, the at least one processor may be further configured to: determine at least one of a time of flight (TOF) or a phase shift between the transmission light and the reflection light; and acquire the information regarding the object located around the vehicle based on the at least one of the TOF or the phase shift between the transmission light and the reflection light. 
     In some implementations, the transmission light may include a Frequency Modulated Continuous Wave (FMCW). 
     In some implementations, the transmission unit may include: an optical generation unit configured to generate the transmission light; and an optical steering unit configured to control a direction of the transmission light. 
     In some implementations, the optical steering unit may include an optical phased array. 
     In some implementations, the transmission unit may further include an optical splitter configured to split an input light into a plurality of beams. 
     In some implementations, the optical phased array of the optical steering unit may be configured to output a plurality of beams that were split by the optical splitter to an outside of the lidar apparatus in a state in which phases of the plurality of beams have been changed. 
     In some implementations, the transmission unit may further include an optical guide unit configured to guide, to the optical steering unit, the plurality of beams that were split by the optical splitter. 
     In some implementations, the lidar apparatus may further include: a heater configured to provide heat to the optical guide unit. The at least one processor may be further configured to control the heater to heat the optical guide unit and change at least one phase of the plurality of beams. 
     In some implementations, the lidar apparatus may further include: a piezoelectric unit configured to apply pressure to the optical guide unit. The at least one processor may be further configured to control the piezoelectric unit to apply pressure to the optical guide unit and change at least one phase of the plurality of beams. 
     In some implementations, the optical guide unit may include a core that is composed of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ), and that includes a cladding structure. 
     In some implementations, the optical guide unit may include: a silicon substrate; a first silicon dioxide layer formed on the silicon substrate; a second silicon dioxide layer formed on the first silicon dioxide layer; a core formed in the second silicon dioxide layer; and a third silicon dioxide layer formed on the second silicon dioxide layer. 
     In some implementations, the optical steering unit may include an optical switch that is configured to switch between different emission directions of the transmission light to adjust an angle of beam steering of the transmission light. 
     In another aspect, a vehicle may include a lidar apparatus according to one or more of the implementations described above. 
     The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. The description and specific examples below are given by way of illustration only, and various changes and modifications will be apparent. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a diagram illustrating an example of the external appearance of a vehicle according to some implementations; 
         FIGS. 1B and 1C  are diagrams illustrating examples of operations of a lidar apparatus for vehicles according to some implementations; 
         FIG. 2  is a block diagram illustrating an example of a vehicle according to some implementations; 
         FIG. 3  is a block diagram illustrating an example of a lidar apparatus for vehicles according to some implementations; 
         FIG. 4  is a block diagram illustrating details of an example of a vehicle lidar apparatus that detects an object through the medium of light; 
         FIG. 5  is a block diagram illustrating an example of operations of transmission light and reception light according to some implementations; 
         FIG. 6A  is a diagram illustrating an example of an optical guide unit according to some implementations; 
         FIG. 6B  is a diagram illustrating an example of some effects and properties of the optical guide unit according to some implementations; 
         FIG. 7  is a diagram illustrating an example of implementing a Frequency Modulated Continuous Wave (FMCW) signal; 
         FIGS. 8A to 8C  are diagrams illustrating examples of implementing a transmission frequency and a reception frequency; 
         FIGS. 9A and 9B  are diagrams illustrating examples of implementing a beat frequency; 
         FIGS. 10A and 10B  are diagrams illustrating examples of an optical steering unit according to an implementation; and 
         FIGS. 11A to 11C  are diagrams illustrating an optical steering unit according to another implementation. 
     
    
    
     DETAILED DESCRIPTION 
     Implementations are disclosed herein that provide a light detection and ranging (lidar) apparatus for a vehicle that adaptively controls light transmission based on a driving state of the vehicle. 
     In some implementations, the lidar apparatus may be configured to adjust an angle of beam steering of transmission light based on information about travel situations of the vehicle. 
     In some scenarios, implementations of the present disclosure may have one or more effects as follows. 
     First, in some implementations, a single lidar apparatus may be utilized for both short distance and long distance operations, thereby offering flexibility for various situations. 
     Second, in some implementations, the lidar apparatus may perform adaptive control based on an advanced driver assistance system (ADAS) of a vehicle that is being driven. 
     Third, in some implementations, the lidar apparatus may adaptively change transmission light even without rotating a motor. Typically, in scenarios where a lidar apparatus is not rotated by a motor, an object is detected only within a predetermined field of view of the lidar apparatus. As a result, such motor-less configurations may be unable to satisfactorily detect an object in an adaptive manner based on the travel situation of a vehicle. According to implementations disclosed herein, a lidar apparatus may adaptively operate based on different travel situations of the vehicle, even if the lidar apparatus is not rotated by a motor. Consequently, the lidar apparatus may be implemented in a more secure and stable manner to be operated in extreme situations, such as detecting high speed vehicles. 
     Effects of the present disclosure are not limited to the aforementioned effects, and other effects may result from implementations disclosed herein. 
     A vehicle as described in this specification may be any suitable motorized vehicle, such as an automobile, a motorcycle, etc. Hereinafter, description will be given based on an automobile. 
     A vehicle as described in this specification may be powered by a suitable power source, and may be implemented, for example, as an internal combustion engine vehicle including an engine as a power source, a hybrid vehicle including both an engine and an electric motor as a power source, or an electric vehicle including an electric motor as a power source. 
     In the following description, “the left side of the vehicle” refers to the left side in the forward driving direction of the vehicle, and “the right side of the vehicle” refers to the right side in the forward driving direction of the vehicle. 
       FIG. 1A  is a view showing the external appearance of a vehicle according to some implementations. 
     Referring to  FIG. 1A , the vehicle  100  may include a plurality of wheels, which are rotated by a power source, and a steering input device for controlling the direction of travel of the vehicle  100 . 
     In some implementations, the vehicle  100  may be an autonomous vehicle that autonomously performs one or more driving operations of the vehicle. The autonomous vehicle may enable bidirectional switching between an autonomous driving mode and a manual mode, e.g., in response to a user input. When switched to the manual mode, the autonomous vehicle  100  may receive a user control, such as a steering input through a steering input device. 
     The vehicle  100  may include, in some implementations, an advanced driver assistance system, which assists a driver based on information acquired by various kinds of sensors. 
     For example, the Advanced Driver Assistance System (ADAS) may implement features such as Autonomous Emergency Braking (AEB), Adaptive Cruise Control (ACC), Cross Traffic Alert (CTA), Lane Change Assistant (LCA), Forward Collision Warning (FCW), Lane Departure Warning (LDW), Lane Keeping Assist (LKA), Speed Assist System (SAS), Traffic Sign Recognition (TSR), High Beam Assist (HBA), Blind Spot Detection (BSD), Autonomous Emergency Steering (AES), Curve Speed Warning System (CSWS), Smart Parking Assist System (SPAS), Traffic Jam Assist (TJA), and Around View Monitor (AVM). 
     As shown in the example of  FIG. 1A , the vehicle  100  may include a lidar apparatus  400 . In some implementations, the lidar apparatus  400  may be arranged as a sub-component of the advanced driver assistance system. In such scenarios, the advanced driver assistance system may be operated based on information generated by the lidar apparatus  400 . 
     In  FIG. 1A , the lidar apparatus  400  is shown as being disposed at the front of the vehicle. However, the present disclosure is not limited thereto. For example, the lidar apparatus  400  may be disposed at the rear, the side, or the roof of the vehicle. In some implementations, the vehicle  100  may include a plurality of lidar apparatuses  400 . 
     In the description below, the overall length of the vehicle  100  refers to the length from the front end to the rear end of the vehicle  100 , the overall width of the vehicle  100  refers to the width of the vehicle  100 , and the overall height of the vehicle  100  refers to the height from the bottom of the wheel to the roof of the vehicle  100 . In the following description, the overall length direction L may refer to the reference direction for the measurement of the overall length of the vehicle  100 , the overall width direction W may refer to the reference direction for the measurement of the overall width of the vehicle  100 , and the overall height direction H may refer to the reference direction for the measurement of the overall height of the vehicle  100 . 
       FIGS. 1B and 1C  are reference views illustrating operation of a lidar apparatus for vehicles according to some implementations. 
     The vehicle  100  may include at least one lidar apparatus (e.g., lidar apparatus  400  of  FIG. 1A ). The lidar apparatus  400  may be mounted to the outside of the vehicle  100 , which defines the external appearance of the vehicle  100 . For example, the lidar apparatus  400  may be mounted to the front bumper, the radiator grill, the hood, the roof, a door, a side mirror, the tailgate, the trunk lid, or the fender of the vehicle  100 . 
     In some implementations, the vehicle  100  may include a plurality of lidar apparatuses  400 . The plurality of lidar apparatuses  400  may detect objects in different directions from the vehicle. For example, the lidar apparatuses  400  may include a first lidar apparatus for detecting an object located in front of the vehicle  100  and a second lidar apparatus for detecting an object located at the rear of the vehicle  100 . In some implementations, the lidar apparatuses  400  may further include a third lidar apparatus for detecting an object located at the left side of the vehicle  100  and a fourth lidar apparatus for detecting an object located at the right side of the vehicle  100 . 
     The lidar apparatus  400  may perform optical type beam steering. To this end, the lidar apparatus  400  may include an optical steering unit (e.g., beam steering unit  530  in  FIG. 5 ). The lidar apparatus  400  may control the beam steering unit to perform adaptive beam steering to detect objects in different directions and in different situations. For example, the lidar apparatus  400  may adjust an angle of beam steering of transmission light based on information about travel situations. 
     Through the use of beam steering, the field of view or the measurement range of the lidar apparatus  400  may be adjusted by adjusting the angle of beam steering of transmission light. For example, in the case where the field of view of the lidar apparatus  400  is increased, the measurement range of the lidar apparatus  400  is decreased. In the case where the field of view of the lidar apparatus  400  is decreased, the measurement range of the lidar apparatus  400  is increased. 
     As shown in  FIG. 1B , the lidar apparatus  400  may set the detection area of an object by adjusting the angle of beam steering of transmission light under the control of at least one processor (e.g., processor  470  in  FIG. 3 ). For example, the processor  470  may adjust the side-to-side angle of beam steering of transmission light in the horizontal direction. In another example, the processor  470  may adjust the up-and-down angle of beam steering of transmission light in the vertical direction. 
     As such, the lidar apparatus may adaptively control the angle of beam steering to detect different areas around the vehicle. For example, as shown in  FIG. 1B , the lidar apparatus  400  may set a first area  11 , a second area  12 , a third area  13 , and a fourth area  14  as the detection area in the horizontal direction under the control of the processor  470 . In another example, the lidar apparatus  400  may set a fifth area  21  and a sixth area  22  as the detection area in the vertical direction under the control of the processor  470 . 
     In some implementations, the lidar apparatus  400  may adjust the angle of beam steering of transmission light based on information about travel situations of the vehicle. The information about travel situations may be detected by the lidar apparatus  400 , for example. Alternatively or additionally, the information about travel situations may be detected by an inner sensing unit (e.g., inner sensing unit  125  in  FIG. 2 ) or an outer sensing unit (e.g., outer sensing unit  126  in  FIG. 2 ), or may be received from any suitable source of the information. 
     In some implementations, the processor  470  of the lidar apparatus  400  may set the number of frames per second (FPS) of the lidar apparatus  400  based on the information about travel situations or the set field of view. 
     In some implementations, the processor  470  of the lidar apparatus  400  may set the resolution of the lidar apparatus  400  based on the information about travel situations or the set field of view. 
     For example, in a scenario where the vehicle  100  is in a first travel situation, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 140 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 20 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 0 m to 30 m from the center of the lidar apparatus  400 . In this case, the number of frames per second (FPS) of the lidar apparatus  400  may be set to 20 Hz. In this case, the range resolution of the lidar apparatus  400  may be set to 5 cm to 10 cm. 
     As another example, in a scenario where the vehicle  100  is in a second travel situation, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 80 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 20 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 30 m to 50 m from the center of the lidar apparatus  400 . In this case, the number of frames per second (FPS) of the lidar apparatus  400  may be set to 20 Hz. In this case, the range resolution of the lidar apparatus  400  may be set to 10 cm. 
     As yet another example, in a scenario where the vehicle  100  is in a third travel situation, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 60 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 10 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 50 m to 100 m from the center of the lidar apparatus  400 . In this case, the number of frames per second (FPS) of the lidar apparatus  400  may be set to 40 Hz. In this case, the range resolution of the lidar apparatus  400  may be set to 10 cm. 
     As a further example, in a scenario where the vehicle  100  is in a fourth travel situation, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 30 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 10 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 100 m to 200 m from the center of the lidar apparatus  400 . In this case, the range resolution of the lidar apparatus  400  may be set to 10 cm to 15 cm. 
     In some implementations, the travel situations of the vehicle may depend on certain properties of the vehicle. For example, the travel situation of the vehicle may correspond to the speed of the vehicle. In this case, a first travel situation may correspond to the speed of the vehicle being less than 30 km/h, a second travel situation may correspond to the speed of the vehicle being equal to or greater than 30 km/h and less than 50 km/h, a third travel situation may correspond to the speed of the vehicle being equal to or greater than 50 km/h and less than 100 km/h, and a fourth travel situation may correspond to the speed of the vehicle being equal to or greater than 100 km/h and less than 200 km/h. 
     The lidar apparatus  400  may be configured to adjust the angle of beam steering based on various types of information about the vehicle. For example, such information may include information about the attitude of the vehicle, information about the direction of the vehicle, information about the location of the vehicle, information about the angle of the vehicle, information about the acceleration of the vehicle, information about the tilt of the vehicle, information about forward/reverse movement of the vehicle, information about the angle of the steering wheel, information about the pressure applied to an accelerator pedal, or information about the pressure applied to a brake pedal, in addition to the information about the speed of the vehicle, described with reference to  FIG. 1B . 
     As shown in the example of  FIG. 1C , the lidar apparatus (e.g., lidar apparatus  400  in  FIG. 1A ) of vehicle  100  may adjust the angle of beam steering of transmission light based on the distance  31  between the vehicle  100  and an object  30  (e.g., another vehicle). The distance  31  between the vehicle  100  and the object  30  may be one example of information about travel situations of the vehicle  100 . 
     In some implementations, the processor  470  of the lidar apparatus  400  of vehicle  100  may set a frames per second (FPS) of the lidar apparatus  400  based on the information about travel situations or based on the set field of view. 
     In some implementations, the processor  470  of the lidar apparatus  400  may set the resolution of the lidar apparatus  400  based on the information about travel situations or based on the set field of view. 
     For example, in the case in which the distance  31  between the vehicle  100  and the object  30  is within a first range, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 140 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 20 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 0 m to 30 m from the center of the lidar apparatus  400 . In this case, the number of frames per second (FPS) of the lidar apparatus  400  may be set to 20 Hz. In this case, the range resolution of the lidar apparatus  400  may be set to 5 cm to 10 cm. 
     As another example, in the case in which the distance  31  between the vehicle  100  and the object  30  is within a second range, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 80 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 20 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 30 m to 50 m from the center of the lidar apparatus  400 . In this case, the number of frames per second (FPS) of the lidar apparatus  400  may be set to 20 Hz. In this case, the range resolution of the lidar apparatus  400  may be set to 10 cm. 
     As still another example, in the case in which the distance  31  between the vehicle  100  and the object  30  is within a third range, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 60 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 10 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 50 m to 100 m from the center of the lidar apparatus  400 . In this case, the number of frames per second (FPS) of the lidar apparatus  400  may be set to 40 Hz. In this case, the range resolution of the lidar apparatus  400  may be set to 10 cm. 
     As a further example, in the case in which the distance  31  between the vehicle  100  and the object  30  is within a fourth range, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 30 degrees in the horizontal direction. In addition, the field of view of the lidar apparatus  400  may be set such that the lidar apparatus  400  has a field of view of 10 degrees in the vertical direction. In this case, the detection distance may be a distance having a radius of 100 m to 200 m from the center of the lidar apparatus  400 . In this case, the range resolution of the lidar apparatus  400  may be set to 10 cm to 15 cm. 
     In some implementations, the lidar apparatus  400  may adjust the angle of beam steering based on other properties of object  30 , such as the speed of the vehicle  100  relative to the object  30  or based on the location of the object  30 , in addition to the distance  31  between the vehicle  100  and the object  30 . 
     The object  30  may be any suitable object outside the vehicle, such as a lane on the road, a nearby vehicle, a pedestrian, a light, a traffic signal, a road, a structure, a bump, a geographical feature, an animal, etc. 
       FIG. 2  is a reference block diagram illustrating an example of the vehicle according to some implementations. 
     Referring to  FIG. 2 , the vehicle  100  may include a communication unit  110 , an input unit  120 , a sensing unit  135 , a memory  130 , an output unit  140 , a vehicle drive unit  150 , a controller  170 , an interface unit  180 , a power supply unit  190 , an advanced driver assistance system  200 , and a lidar apparatus  400 . 
     The communication unit  110  may include a short-range communication module  113 , a location information module  114 , an optical communication module  115 , and a V2X communication module  116 . 
     The communication unit  110  may include one or more Radio Frequency (RF) circuits or elements in order to perform communication with other devices. 
     The short-range communication module  113  may support short-range communication using at least one selected from among Bluetooth™, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra-WideBand (UWB), ZigBee, Near Field Communication (NFC), Wireless-Fidelity (Wi-Fi), Wi-Fi Direct, and Wireless USB (Wireless Universal Serial Bus). 
     The short-range communication module  113  may form wireless area networks to perform short-range communication between the vehicle  100  and at least one external device. For example, the short-range communication module  113  may exchange data with a mobile terminal of a passenger in a wireless manner. The short-range communication module  113  may receive weather information and road traffic state information (e.g. Transport Protocol Expert Group (TPEG) information) from the mobile terminal. When a user gets into the vehicle  100 , the mobile terminal of the user and the vehicle  100  may pair with each other automatically or as the result of the user executing a pairing application. 
     The location information module  114  is a module for acquiring the location of the vehicle  100 . A representative example of the location information module  114  includes a Global Positioning System (GPS) module. For example, when the vehicle  100  utilizes the GPS module, the location of the vehicle  100  may be acquired using signals transmitted from GPS satellites. 
     In some implementations, the location information module  114  may be a component included in the sensing unit  135 , rather than a component included in the communication unit  110 . 
     The optical communication module  115  may include a light emitting unit and a light receiving unit. 
     The light receiving unit may convert light into electrical signals so as to receive information. The light receiving unit may include Photodiodes (PDs) for receiving light. The photo diodes may convert light into electrical signals. For example, the light receiving unit may receive information regarding a preceding vehicle from light emitted from a light source included in the preceding vehicle. 
     The light emitting unit may include at least one light emitting element for converting electrical signals into light. Here, the light emitting element may be a Light Emitting Diode (LED) or a Laser Diode (LD). The light emitting unit converts electrical signals into light to thereby emit the light. For example, the light emitting unit may externally emit light by flashing the light emitting element at a predetermined frequency. In some implementations, the light emitting unit may include an array of light emitting elements. In some implementations, the light emitting unit may be integrated with a lamp provided in the vehicle  100 . For example, the light emitting unit may be at least one selected from among a headlight, a taillight, a brake light, a turn signal light, and a sidelight. For example, the optical communication module  115  may exchange data with another vehicle through optical communication. 
     The V2X communication module  116  is a module for performing wireless communication with a server or another vehicle. The V2X communication module  116  includes a module capable of supporting a protocol for communication between vehicles (V2V) or communication between a vehicle and some infrastructure (V2I). The vehicle  100  may perform wireless communication with an external server or another vehicle via the V2X communication module  116 . 
     The input unit  120  may include a driving operation device  121 , a microphone  123 , and a user input unit  124 . 
     The driving operation device  121  receives a user input for driving of the vehicle  100 . The driving operation device  121  may include a steering input device, a shift input device, an acceleration input device, and a brake input device. 
     The steering input device receives a user input with regard to the direction of travel of the vehicle  100 . The steering input device may take the form of a wheel to enable a steering input through the rotation thereof. In some implementations, the steering input device may be configured as a touchscreen, a touch pad, or a button. 
     The shift input device receives an input for selecting one of Park (P), Drive (D), Neutral (N), and Reverse (R) gears of the vehicle  100  from the user. The shift input device may take the form of a lever. In some implementations, the shift input device may be configured as a touchscreen, a touch pad, or a button. 
     The acceleration input device receives a user input for acceleration of the vehicle  100 . 
     The brake input device receives a user input for deceleration of the vehicle  100 . Each of the acceleration input device and the brake input device may take the form of a pedal. In some implementations, the acceleration input device or the brake input device may be configured as a touchscreen, a touch pad, or a button. 
     The microphone  123  may process external sound signals into electrical data. The processed data may be utilized in various ways in accordance with the function that the vehicle  100  is performing. The microphone  123  may convert a user voice command into electrical data. The converted electrical data may be transmitted to the controller  170 . 
     In some implementations, the microphone  123  may be a component included in the sensing unit  135 , rather than a component included in the input unit  120 . 
     The user input unit  124  is configured to receive information from the user. When information is input through the user input unit  124 , the controller  170  may control the operation of the vehicle  100  according to the input information. The user input unit  124  may include a touch input unit or a mechanical input unit. In some implementations, the user input unit  124  may be located in the region of the steering wheel. In this case, the driver may operate the user input unit  124  with the fingers while gripping the steering wheel. 
     The sensing unit  135  may sense the state of the vehicle  100  or the situation outside the vehicle  100 . The sensing unit  135  may include an inner sensing unit  125  and an outer sensing unit  126 . 
     The inner sensing unit  125  senses the state of the vehicle  100 . The inner sensing unit  125  may include an attitude sensor (for example, a yaw sensor, a roll sensor, or a pitch sensor), a collision sensor, a wheel sensor, a speed sensor, a gradient sensor, a weight sensor, a heading sensor, a yaw sensor, a gyro sensor, a position module, a vehicle forward/reverse movement sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor based on the rotation of the steering wheel, an in-vehicle temperature sensor, an in-vehicle humidity sensor, an ultrasonic sensor, an illumination sensor, an accelerator pedal position sensor, and a brake pedal position sensor. 
     The inner sensing unit  125  may acquire sensing signals with regard to, for example, vehicle attitude information, vehicle collision information, vehicle driving direction information, vehicle location information (GPS information), vehicle angle information, vehicle speed information, vehicle acceleration information, vehicle tilt information, vehicle forward/reverse movement information, battery information, fuel information, tire information, vehicle lamp information, in-vehicle temperature information, in-vehicle humidity information, steering-wheel rotation angle information, out-of-vehicle illumination information, information about the pressure applied to an accelerator pedal, and information about the pressure applied to a brake pedal. 
     The inner sensing unit  125  may further include, for example, an accelerator pedal sensor, a pressure sensor, an engine speed sensor, an Air Flow-rate Sensor (AFS), an Air Temperature Sensor (ATS), a Water Temperature Sensor (WTS), a Throttle Position Sensor (TPS), a Top Dead Center (TDC) sensor, and a Crank Angle Sensor (CAS). 
     The outer sensing unit  126  may sense the situation outside the vehicle  100 . The outer sensing unit  126  may sense an object located outside the vehicle. Here, the object may include a lane, a nearby vehicle, a pedestrian, a light, a traffic signal, a road, a structure, a bump, a geographical feature, and an animal. 
     The lane may be the lane in which the vehicle  100  is traveling or the lane next to the lane in which the vehicle  100  is traveling. The lane may include left and right lines that define the lane. 
     The nearby vehicle may be a vehicle that is traveling in the vicinity of the vehicle  100 . The nearby vehicle may be a vehicle spaced apart from the vehicle  100  by a predetermined distance or less. The nearby vehicle may be a preceding vehicle or a following vehicle. The nearby vehicle may be a vehicle that is traveling in the lane next to the lane in which the vehicle  100  is traveling. The nearby vehicle may be a vehicle that is traveling in the direction intersecting the direction in which the vehicle  100  is traveling at an intersection. 
     The pedestrian may be a person on a sidewalk or on the roadway. 
     The light may be light generated by a lamp provided in the nearby vehicle. The light may be light generated by a streetlight. The light may be solar light. 
     The traffic signal may include a traffic signal lamp, a traffic sign, and a pattern or text painted on a road surface. 
     The road may include a road surface, a curve, and slopes, such as an upward slope and a downward slope. 
     The structure may be a body located around the road in the state of being fixed to the ground. For example, the structure may include a streetlight, a roadside tree, a building, and a signal lamp. 
     The geographical feature may include a mountain and a hill. 
     The object may be classified as a movable object or a stationary object. For example, a movable object may include a nearby vehicle or a pedestrian, etc. A stationary object may include a traffic signal, a road, or a structure, etc. 
     The outer sensing unit  126  may include a camera  202 , a radar  201 , and/or an ultrasonic sensor  203 , to name a few examples. 
     The camera  202  may be a camera device for vehicles. The camera  202  may include a mono camera and/or a stereo camera. 
     The camera  202  may be located at an appropriate position outside the vehicle in order to acquire images of the outside of the vehicle. 
     For example, the camera  202  may be disposed near a front windshield  10  in the vehicle in order to acquire images of the front of the vehicle. Alternatively, the camera  202  may be disposed around a front bumper or a radiator grill. 
     For example, the camera  202  may be disposed near a rear glass in the vehicle in order to acquire images of the rear of the vehicle. Alternatively, the camera  202  may be disposed around a rear bumper, a trunk, or a tailgate. 
     For example, the camera  202  may be disposed near at least one of the side windows in the vehicle in order to acquire images of the side of the vehicle. Alternatively, the camera  202  may be disposed around a side mirror, a fender, or a door. 
     The radar  201  may include an electromagnetic wave transmission unit, an electromagnetic wave reception unit, and a processor. The radar  201  may be realized as a pulse radar or a continuous wave radar depending on the principle of emission of an electric wave. In addition, the continuous wave radar may be realized as a Frequency Modulated Continuous Wave (FMCW) type radar or a Frequency Shift Keying (FSK) type radar depending on the waveform of a signal. 
     The radar  201  may detect an object based on a transmitted electromagnetic wave, and may detect the distance to the detected object and the speed relative to the detected object. 
     The radar  201  may provide the acquired information about the object to the controller  170 , the advanced driver assistance system  200 , or an illumination device for vehicles. Here, the information about the object may include information about the distance to the object. 
     The radar  201  may be located at an appropriate position outside the vehicle in order to sense an object located in front of the vehicle, an object located to the rear of the vehicle, or an object located to the side of the vehicle. 
     The ultrasonic sensor  203  may include an ultrasonic wave transmission unit, an ultrasonic wave reception unit, and a processor. 
     The ultrasonic sensor  203  may detect an object based on a transmitted ultrasonic wave, and may detect the distance to the detected object and the speed relative to the detected object. 
     The ultrasonic sensor  203  may provide the acquired information about the object to the controller  170 , the advanced driver assistance system  200 , or the illumination device for vehicles. Here, the information about the object may include information about the distance to the object. 
     The ultrasonic sensor  203  may be located at an appropriate position outside the vehicle in order to sense an object located in front of the vehicle, an object located to the rear of the vehicle, or an object located to the side of the vehicle. 
     In some implementations, the lidar apparatus  400  may be arranged as a sub-component of the outer sensing unit  126 . 
     The memory  130  is electrically connected to at least one processor, such as controller  170 . The memory  130  may store basic data for each unit, control data for the operational control of each unit, and input/output data. The memory  130  may be any of various hardware storage devices, such as a ROM, a RAM, an EPROM, a flash drive, and a hard drive. The memory  130  may store various data for the overall operation of the vehicle  100 , such as programs for the processing or control of the controller  170 . 
     The output unit  140  is configured to output information processed in the controller  170 . The output unit  140  may include a display device  141 , a sound output unit  142 , and a haptic output unit  143 . 
     The display device  141  may display various graphic objects. For example, the display device  141  may display vehicle-associated information. Here, the vehicle-associated information may include vehicle control information for the direct control of the vehicle or driver assistance information to guide the driver in driving the vehicle. In addition, the vehicle associated information may include vehicle state information indicating the current state of the vehicle or vehicle traveling information regarding the traveling of the vehicle. 
     The display device  141  may include at least one selected from among a Liquid Crystal Display (LCD), a Thin Film Transistor LCD (TFT LCD), an Organic Light Emitting Diode (OLED), a flexible display, a three-dimensional display (3D display), and an e-ink display. 
     The display device  141  may form an inter-layer structure together with a touch sensor, or may be integrally formed with the touch sensor to implement a touchscreen. The touchscreen may function as the user input unit  124 , which provides an input interface between the vehicle  100  and the user, and may also function to provide an output interface between the vehicle  100  and the user. In this case, the display device  141  may include a touch sensor for sensing a touch on the display device  141  so as to receive a control command in a touch manner. When a touch is input to the display device  141  as described above, the touch sensor may sense the touch, and the controller  170  may generate a control command corresponding to the touch. The content input in a touch manner may be characters or numbers, or may be, for example, instructions in various modes or menu items that may be designated. 
     The display device  141  may include a cluster for allowing the driver to check vehicle state information or vehicle traveling information while driving the vehicle. The cluster may be located on a dashboard. In this case, the driver may check information displayed on the cluster while looking forward. 
     In some implementations, the display device  141  may be implemented as a Head Up display (HUD). When the display device  141  is implemented as a HUD, information may be output through a transparent display provided on the front windshield  10 . Alternatively, the display device  141  may include a projector module in order to output information through an image projected on the front windshield  10 . 
     In some implementations, the display device  141  may include a transparent display. In this case, the transparent display may be attached to the front windshield  10 . 
     The transparent display may display a predetermined screen with a predetermined transparency. In order to achieve the transparency, the transparent display may include at least one selected from among a transparent Thin Film Electroluminescent (TFEL) display, an Organic Light Emitting Diode (OLED) display, a transparent Liquid Crystal Display (LCD), a transmissive transparent display, and a transparent LED display. The transparency of the transparent display may be adjustable. 
     In some implementations, the display device  141  may function as a navigation device. 
     The sound output unit  142  converts electrical signals from the controller  170  into audio signals and outputs the audio signals. To this end, the sound output unit  142  may include, for example, a speaker. The sound output unit  142  may output sound corresponding to the operation of the user input unit  124 . 
     The haptic output unit  143  generates a tactile output. For example, the haptic output unit  143  may operate to vibrate a steering wheel, a safety belt, or a seat so as to allow the user to recognize the output thereof. 
     The vehicle drive unit  150  may control the operation of various devices of the vehicle. The vehicle drive unit  150  may include a power source drive unit  151 , a steering drive unit  152 , a brake drive unit  153 , a lamp drive unit  154 , an air conditioner drive unit  155 , a window drive unit  156 , an airbag drive unit  157 , a sunroof drive unit  158 , and a suspension drive unit  159 . 
     The power source drive unit  151  may perform electronic control of a power source inside the vehicle  100 . 
     For example, in the case in which a fossil fuel-based engine is the power source, the power source drive unit  151  may perform electronic control of the engine. As such, the power source drive unit  151  may control, for example, the output torque of the engine. In the case in which the power source drive unit  151  is such an engine, the power source drive unit  151  may limit the speed of the vehicle by controlling the output torque of the engine under the control of the controller  170 . 
     In another example, when an electric motor is the power source, the power source drive unit  151  may perform control of the motor. As such, the power source drive unit  151  may control, for example, the RPM and torque of the motor. 
     The steering drive unit  152  may perform electronic control of a steering apparatus inside the vehicle  100 . As such, the steering drive unit  152  may change the direction of travel of the vehicle  100 . 
     The brake drive unit  153  may perform electronic control for a brake apparatus inside the vehicle  100 . For example, the brake drive unit  153  may reduce the speed of the vehicle  100  by controlling the operation of brakes located at wheels. In another example, the brake drive unit  153  may adjust the direction of travel of the vehicle  100  leftward or rightward by differently operating respective brakes located at left and right wheels. 
     The lamp drive unit  154  may turn at least one lamp, arranged inside or outside the vehicle, on or off. In addition, the lamp drive unit  154  may control, for example, the intensity and radiation direction of the light from the lamp. For example, the lamp drive unit  154  may perform control for a turn-signal lamp or a brake lamp. 
     The air conditioner drive unit  155  may perform electronic control of an air conditioner inside the vehicle  100 . For example, when the interior temperature of the vehicle is high, the air conditioner drive unit  155  may operate the air conditioner so as to supply cool air to the interior of the vehicle. 
     The window drive unit  156  may perform electronic control of a window apparatus inside the vehicle  100 . For example, the window drive unit  156  may control the opening or closing of left and right windows of the vehicle. 
     The airbag drive unit  157  may perform electronic control of an airbag apparatus inside the vehicle  100 . For example, the airbag drive unit  157  may perform control such that an airbag is deployed in a dangerous situation. 
     The sunroof drive unit  158  may perform electronic control of a sunroof apparatus inside the vehicle  100 . For example, the sunroof drive unit  158  may control the opening or closing of a sunroof. 
     The suspension drive unit  159  may perform electronic control of a suspension apparatus inside the vehicle  100 . For example, when the road surface is uneven, the suspension drive unit  159  may control the suspension apparatus in order to reduce the vibration of the vehicle  100 . 
     In some implementations, the vehicle drive unit  150  may include a chassis drive unit. Here, the chassis drive unit may include the steering drive unit  152 , the brake drive unit  153 , and the suspension drive unit  159 . 
     The controller  170  may control the overall operation of each unit inside the vehicle  100 . The controller  170  may be referred to as an Electronic Control Unit (ECU). 
     The controller  170  may be implemented in a hardware manner using at least one selected from among Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, and electric units for the implementation of other functions. 
     The interface unit  180  may serve as a passage for various kinds of external devices that are connected to the vehicle  100 . For example, the interface unit  180  may have a port that is connectable to a mobile terminal and may be connected to the mobile terminal via the port. In this case, the interface unit  180  may exchange data with the mobile terminal. 
     The interface unit  180  may serve as a passage for the supply of electrical energy to a mobile terminal connected thereto. When the mobile terminal is electrically connected to the interface unit  180 , the interface unit  180  may provide electrical energy, supplied from the power supply unit  190 , to the mobile terminal under the control of the controller  170 . 
     The power supply unit  190  may supply power required to operate the respective components under the control of the controller  170 . In particular, the power supply unit  190  may receive power from, for example, a battery inside the vehicle  100 . 
     The advanced driver assistance system  200  may assist a driver in driving the vehicle. The advanced driver assistance system  200  may include the lidar apparatus  400 . 
     The lidar apparatus  400  may detect an object located outside the vehicle  100 . 
     The lidar apparatus  400  may detect an object based on the time of flight (TOF) or the phase difference between a transmission signal and a reception signal through the medium of light. 
     The lidar apparatus  400  may detect the distance to the object, the speed relative to the object, and the location of the object. 
       FIG. 3  is a reference block diagram illustrating an example of a lidar apparatus for vehicles according to some implementations. 
     Referring to  FIG. 3 , the lidar apparatus  400  may include a transmission unit  410 , a reception unit  420 , a memory  440 , an interface unit  430 , at least one processor  470 , and a power supply unit  490 . In some implementation, at least one of the above-mentioned components of the lidar apparatus  400  may be omitted, or the lidar apparatus  400  may further include at least one additional component. 
     The transmission unit  410  may generate and output a transmission signal. The transmission unit  410  may be controlled by at least one processor  470 . 
     The transmission unit  410  may output a transmission signal in the form of light. In this case, the transmission unit  410  may include an optical generation unit  417  (see  FIG. 4 ). The optical generation unit  417  may convert an electrical signal into light. For example, the optical generation unit  417  may include a laser generation unit. In this case, a transmission signal may be realized as an optical signal. 
     For example, the transmission unit  410  may output a transmission signal in the form of a Frequency Modulated Continuous Wave (FMCW). That is, the transmission signal may be realized in the form of an FMCW. 
     The transmission unit  410  may perform beam steering of the light generated by the optical generation unit  417 . For example, the transmission unit  410  may change the path of the light generated by the optical generation unit  417  in order to perform beam steering of the light. 
     The transmission unit  410  may perform scanning through the steered light. 
     The transmission unit  410  may include an optical generation unit (e.g.,  417  in  FIG. 5 ), an optical splitter (e.g.,  510  in  FIG. 5 ), an optical guide unit (e.g.,  520  in  FIG. 5 ), and an optical steering unit (e.g.,  530  in  FIG. 5 ). 
     The optical generation unit  417  may generate light corresponding to a transmission signal, and may output the optical signal to the outside. The optical generation unit  417  may generate transmission light, and may output the generated transmission light to the outside. 
     The light generated by the optical generation unit  417  may be a laser. 
     In optical splitter (e.g., optical splitter  510  in  FIG. 5 ) may split the transmission light generated by the optical generation unit  417  into a plurality of beams. 
     An optical guide unit (e.g., optical guide unit  520  in  FIG. 5 ) may guide the plurality of beams split by the optical splitter towards an optical steering unit (e.g., optical steering unit  530  in  FIG. 5 ). 
     The optical steering unit  530  may perform beam steering of the light generated by the optical generation unit  417 . For example, the optical steering unit  530  may continuously change the path of light introduced thereinto. In some implementations, the optical steering unit  530  may perform a scanning-type detection by changing the direction of steering of light. 
     Two different implementations of the optical steering unit  530  will be described further below with reference to  FIGS. 10A-10B  and  FIGS. 11A-11C . These two implementations utilize different hardware and different techniques to achieve the general feature of adaptively steering one or more beams. 
     The implementation of  FIGS. 10A and 10B  provides an optical steering unit  530  that includes an optical phased array, which may have a plurality of individual arrays. As such, the plurality of individual arrays in the optical phased array of optical steering unit  520  may receive the plurality of beams that were split by optical splitter  510  and that have different phases. 
     The implementation of  FIGS. 11A to 11C  provides an optical steering unit  530  that includes an optical switch. The optical switch may be controlled to change the emission angle of the transmission light to adjust the angle of the beam steering. 
     In some implementations, the transmission unit  410  may include an optical coupler in place of the optical splitter  510  (see  FIG. 5 ). The optical coupler may perform light division and light combination. 
     The reception unit  420  may acquire a reception signal. Here, the reception signal is a signal formed as the result of the transmission signal being reflected by an object. The reception unit  420  may be controlled by at least one processor  470 . 
     The reception unit  420  may acquire reflection light, which is formed as the result of the transmission signal being reflected by the object. 
     In the case in which an FMCW signal is output as a transmission signal, the reception unit  420  may acquire a reception signal as an FMCW signal. 
     In the case in which an object is detected through the medium of an optical signal, the reception unit  420  may include a photo detector  421  (see  FIG. 4 ). The photo detector  421  may convert light into electricity. For example, the photo detector  421  may include a photo diode (PD). 
     The reception unit  420  may include a photo diode (PD) array. In this case, one photo diode may form one pixel. The processor  470  may generate an image based on information sensed by the respective photo diodes of the photo diode array. 
     The reception unit  420  may receive light reflected from respective points of the transmission light that is scanned. For example, when transmission light is output toward a first point, the reception unit  420  may receive light reflected from the first point. In addition, when transmission light is output toward a second point, the reception unit  420  may receive light reflected from the second point. In this way, the reception unit  420  may continuously receive light reflected from a plurality of points in order to sense the reflection light from each point. Each point may be defined as one pixel. The processor  470  may generate an image based on the information sensed at each point. 
     The memory  440  may store various kinds of data for the overall operation of the lidar apparatus  400 , such as programs for the processing or control of the processor  470 . The memory  440  may be any one of various hardware storage devices, such as a ROM, a RAM, an EPROM, a flash drive, and a hard drive. 
     The interface unit  430  may function as a path for allowing the lidar apparatus  400  to exchange data with a device connected to the lidar apparatus  400  therethrough. The interface unit  430  may receive data from a unit that is electrically connected to the lidar apparatus  400 , and may transmit a signal processed or generated by the processor  470  to the unit that is electrically connected to the lidar apparatus  400 . The interface unit  430  may function as a path for allowing the lidar apparatus  400  to exchange data with a controller of the advanced driver assistance system  200  or with the controller  170  of the vehicle  100  therethrough. 
     The interface unit  430  may receive information or data from the controller of the advanced driver assistance system  200 . For example, the interface unit  430  may receive information about an expected collision time from the controller of the advanced driver assistance system  200 . For example, the interface unit  430  may receive information about the distance to an object from the controller of the advanced driver assistance system  200 . 
     The interface unit  430  may transmit signals, data, or information to the other devices in the vehicle  100 . 
     For example, the interface unit  430  may provide signals, data, or information generated by the processor  470  to another object sensing device in the vehicle  100 . 
     The interface unit  430  may receive information about travel situations from the inner sensing unit  125  (see  FIG. 2 ) or the outer sensing unit  126  (see  FIG. 2 ) of the vehicle  100 . 
     The information about travel situations may include at least one selected from between information sensed in the vehicle and information sensed outside the vehicle. The information sensed in the vehicle may be information sensed and generated by the inner sensing unit  125 . The information sensed outside the vehicle may be information sensed and generated by the outer sensing unit  126 . 
     The processor  470  may be electrically connected to the respective units in the lidar apparatus  400  so as to control the overall operation of the respective units. 
     The processor  470  may compare a reflection signal with a transmission signal to acquire information about an object. For example, the processor  470  may compare reflection light with transmission light to acquire information about an object. 
     For example, the processor  470  may calculate the time of flight (TOF) or the phase shift between the transmission light and the reflection light in order to acquire information about an object. 
     Information about an object may include information about whether an object is present or not, information about the distance to an object, information about the speed relative to an object, and information about the location of an object. 
     The processor  470  may generate an image of the object based on the transmission light and the reception light. Specifically, the processor  470  may compare transmission light with reception light corresponding to each pixel to generate an image of the object. For example, the processor  470  may compare transmission light with reception light corresponding to each pixel to calculate the TOF or the phase shift for each pixel, thereby generating an image of the object. 
     The processor  470  may receive information about travel situations from the inner sensing unit  125  or the outer sensing unit  126  through the interface unit  430 . 
     The information about travel situations may include at least one selected from between information sensed in the vehicle and information sensed outside the vehicle. 
     The information sensed in the vehicle may be information sensed and generated by the inner sensing unit  125 . For example, the information sensed in the vehicle may include at least one selected from among vehicle attitude information, vehicle driving direction information, vehicle location information, vehicle angle information, vehicle speed information, vehicle acceleration information, vehicle tilt information, vehicle forward/reverse movement information, steering-wheel rotation angle information, information about the pressure applied to an accelerator pedal, and information about the pressure applied to a brake pedal. 
     The information sensed outside the vehicle may be information sensed and generated by the outer sensing unit  126 . For example, the information sensed outside the vehicle may include information about an object located outside the vehicle. Such information about an object may include information about whether an object is present or not, information about the distance to an object, information about the speed relative to an object, and information about the location of an object. 
     The object may be any suitable object outside the vehicle, such as a lane in the road, a nearby vehicle, a pedestrian, a light, a traffic signal, a road, a structure, a bump, a geographical feature, an animal, etc. 
     Information about travel situations may be information about an object located in the vicinity of the vehicle. Here, the information about the object may be information generated by the processor  470  based on reflection light. 
     The processor  470  may generate the information about the object based on the reflection light, and may adjust the angle of the beam steering of the transmission light based on the generated information about the object. 
     The processor  470  may adjust the angle of the beam steering of the transmission light based on the information about travel situations. 
     The processor  470  may adjust the field of view (FOV) of the transmission light by adjusting the angle of the beam steering of the transmission light. 
     The processor  470  may set the detection area of the object by adjusting the angle of the beam steering of the transmission light. 
     For example, the processor  470  may adjust the side-to-side angle of beam steering of the transmission light in the horizontal direction. The processor  470  may adjust the up-and-down angle of beam steering of the transmission light in the vertical direction. 
     The processor  470  may control a heater  482  so as to change the individual phases of beams split by the optical splitter  510 . 
     The processor  470  may control a piezoelectric unit  484  so as to change the individual phases of beams split by the optical splitter  510 . 
     The processor  470  may generate a depth map based on the transmission light and the reflection light. Specifically, the processor  470  may compare transmission light and reflection light corresponding to each pixel to calculate the TOF or the phase shift for each pixel, thereby generating a depth map. 
     The processor  470  may determine whether a disturbance has occurred based on the depth value of a predetermined region of interest (ROI) on the depth map. Specifically, the processor  470  may accumulate the depth value of the region of interest, and may store the accumulated depth values in the memory  440 . The processor  470  may determine whether a disturbance has occurred based on the difference between the average value of the accumulatively stored depth values and a newly acquired depth value of the region of interest. 
     The processor  470  may be implemented using at least one selected from among Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, and electric units for the implementation of other functions. 
     In some implementations, the lidar apparatus  400  may selectively further include one or both of the heater  482  and the piezoelectric unit  484 . 
     The heater  482  may provide heat to the optical guide unit  520  (see  FIGS. 4 and 5 ). 
     The heater  482  may include an element for converting electrical energy into thermal energy. For example, the heater  482  may convert electrical energy into thermal energy using a Peltier effect, and may provide heat to the optical guide unit  520 . 
     When the heater  482  provides heat to the optical guide unit  520 , the phase of light guided by the optical guide unit  520  may be changed. The lidar apparatus  400  may perform beam steering using such phase-changed light. 
     The heater  482  may be operated under the control of the processor  470 . 
     The piezoelectric unit  484  may provide pressure to the optical guide unit  520  (see  FIGS. 4 and 5 ). 
     The piezoelectric unit  484  may include a piezoelectric element. For example, the piezoelectric unit  484  may provide pressure to the optical guide unit  520  using a piezoelectric effect. 
     When the piezoelectric unit  484  provides pressure to the optical guide unit  520 , the phase of light guided by the optical guide unit  520  may be changed. The lidar apparatus  400  may perform beam steering using such changed phase of light. 
     The piezoelectric unit  484  may be operated under the control of the processor  470 . 
     In some implementations, the lidar apparatus  400  may further include an attitude sensing unit  450  and an attitude adjustment unit  460 . 
     The attitude sensing unit  450  may sense the attitude of the lidar apparatus  400 . In order to transmit a transmission signal toward an object located in front of the vehicle, an object located at the rear of the vehicle, or an object located at the side of the vehicle, and to acquire a reception signal reflected by the object, the lidar apparatus  400  must take an appropriate attitude. In the case in which the attitude of the lidar apparatus  400  is changed due to the application of external impact to the vehicle, the attitude sensing unit  450  may sense the change in attitude of the lidar apparatus  400 . 
     In order to sense the attitude of the lidar apparatus  400 , the attitude sensing unit  450  may include at least one selected from among an infrared sensor, a bolt fastening sensor (for example, a bolt magnet sensor), and a gyro sensor. 
     The attitude adjustment unit  460  may adjust the attitude of the lidar apparatus  400  based on the results of sensing by the attitude sensing unit  450 . The attitude adjustment unit  460  may include a driving means, such as a motor. The attitude adjustment unit  460  may adjust the attitude of the lidar apparatus  400  under the control of the processor  470  such that the lidar apparatus  400  can appropriately transmit a transmission signal and appropriately acquire a reception signal. 
     The processor  470  may receive information about the attitude of the lidar apparatus  400  sensed by the attitude sensing unit  450 . The processor  470  may control the attitude adjustment unit  460  based on the received information about the attitude of the lidar apparatus  400 . 
     In some implementations, the processor  470  may control the direction and magnitude of a beam in a transmission signal in the state in which the attitude of the lidar apparatus  400  is maintained. 
     In the case in which the attitude of the lidar apparatus  400 , sensed by the attitude sensing unit  450 , is changed, the processor  470  may provide relevant information to the controller  170  through the interface unit  430 . In this case, the controller  170  may output information about the change in attitude of the lidar apparatus  400  through the output unit  140  such that a user can notice the change in attitude of the lidar apparatus  400 . 
       FIG. 4  is a detailed reference block diagram illustrating an example of the lidar apparatus for vehicles according to some implementations, which detects an object through the medium of light. 
     Referring to  FIG. 4 , the transmission unit  410  may include a waveform generator  411 , a modulator  414 , and an optical generation unit  417 . 
     The waveform generator  411  may generate a transmission signal. To this end, the waveform generator  411  may include an oscillating element, such as a Voltage Controlled Oscillator (VCO). Alternatively, in some implementations, the waveform generator  411  may include a plurality of oscillators. 
     For example, the waveform generator  411  may generate an FMCW signal. The FMCW signal will be described next with reference to  FIG. 7 . 
       FIG. 7  is a reference view illustrating an example of an FMCW signal according to some implementations. 
     Referring to the example of  FIG. 7 , the waveform generator  411  may generate a triangle wave-shaped frequency-modulated continuous wave (FMCW) signal. The transmission unit  410  may output a transmission signal that corresponds to the FMCW signal. The transmission signal that is output may reflect off an object and generate reflection that is received as a reception signal. The lidar apparatus  400  may compare the transmission signal and the reception signal to determine information about a distance to the object. 
     As an example, the lidar apparatus  400  may analyze the spectrum of the frequency of a beat signal (hereinafter, referred to as a beat frequency) that is acquired from a reception signal and a transmission signal (for example, a time domain signal indicating the difference in frequency between a reception signal and a transmission signal) in order to acquire information about the distance to an object and information about the speed of the object. In  FIG. 7 , f c  indicates a center frequency, f 0  indicates a start frequency, B indicates a modulation bandwidth, and T m  indicates a modulation period. 
     An FMCW signal may be classified as an up-chirp signal or a down-chirp signal. 
     Referring back to  FIG. 4 , the modulator  414  may be configured to modulate a carrier with a transmission signal generated by the waveform generator  411 . The carrier may be, for example, light that is generated by the optical generation unit  417 . For example, the modulator  414  may modulate an FMCW signal onto the carrier light. 
     As such, the optical generation unit  417  may generate light corresponding to the transmission signal, and may output an optical signal to the outside. For example, if the optical generation unit  417  outputs light corresponding to the FMCW signal, then the transmission light may be realized as the FMCW signal. 
     The light generated by the optical generation unit  417  may, in some implementations, be a laser. 
     In some implementations, the transmission unit  410  may further include an amplifier. The amplifier may include an amplification circuit. The amplifier may amplify a signal generated by the waveform generator  411 , and may provide the amplified signal to the modulator  414 . 
     The reception unit  420 , which receives the reflected light, may include a photo detector  421  and a mixer  424 . 
     The photo detector  421  may convert reception light into an electrical signal. The photo detector  421  may receive a reflection light signal formed as the result of an optical signal output by the transmission unit  410  being reflected by an object, and may convert the received reflection light signal into an electrical signal. 
     The mixer  424  may correlatively calculate a signal generated by the waveform generator  411  and a signal received by the photo detector  421 , and may output the difference between the two signals. 
     For example, the mixer  424  may generate information about a TOF corresponding to the time difference between a transmission signal output by the transmission unit  410  and a reception signal received by the reception unit  420 . 
     In another example, the mixer  424  may mix a transmission signal generated by the waveform generator  411  and a reception signal received by the photo detector  421 , and may generate a signal corresponding to the difference in frequency between the transmission signal and the reception signal. 
     The frequency of a signal acquired from the transmission signal and the reception signal may be referred to as a beat frequency. The frequency output from the mixer  424  may be a beat frequency. 
     The processor  470  may acquire information about the object based on the difference in frequency between the transmission signal and the reception signal. 
     The reception unit  420  may further include a filter and an amplifier. 
     The filter may filter a signal generated by the mixer  424 . 
     The amplifier may amplify a signal that is generated by the mixer  424  or a signal that is generated by the mixer  424  and filtered by the filter, and may provide the amplified signal to the processor  470 . 
     The processor  470  may include a Fast Fourier Transform (FFT) unit  471 , a processing unit  474 , and a Digital to Analog Converter (DAC) unit  477 . 
     In the case in which a transmission signal and a reception signal are FMCW signals, the FFT unit  471  may measure the frequency of a signal output from the mixer  424  through fast Fourier transform. The FFT unit  471  may generate information about phase shift through fast Fourier transform of a signal corresponding to the difference in frequency between the transmission signal and the reception signal. 
     In some implementations, the FFT unit  471  may be omitted. 
     The processing unit  474  may acquire information about an object. The processing unit  474  may acquire information about an object based on the difference between the transmission signal and the reception signal, which is provided by the mixer  424 . 
     The processing unit  474  may acquire information about an object based on TOF or phase shift. 
     The processing unit  474  may acquire information about an object based on information about TOF provided by the mixer  424 . 
     The processing unit  474  may acquire information about an object based on information about a phase shift (PS). 
     Information about an object may include information about whether or not an object is present, information about the distance to an object, information about the speed relative to an object, and information about the location of an object. 
     Hereinafter, the operation of acquiring object information in the case in which a transmission signal and a reception signal are FMCW signals will be described with reference to  FIGS. 8A to 8C . 
       FIGS. 8A to 8C  are views showing examples of a transmission frequency and a reception frequency according to some implementations. 
       FIGS. 9A and 9B  are reference views illustrating examples of a beat frequency according to some implementations. 
     The operation of acquiring object information will be described with reference to  FIGS. 8A to 9B . 
       FIGS. 8A to 8C  are views showing the relationship between the frequency of a transmission signal (hereinafter, referred to as a transmission frequency) and the frequency of a reception signal (hereinafter, referred to as a reception frequency) on a time axis.  FIG. 8A  shows the case in which an object is stationary,  FIG. 8B  shows the case in which an object approaches the lidar apparatus, and  FIG. 8C  shows the case in which an object becomes distant from the lidar apparatus. 
     In  FIGS. 8A to 8C , t d  indicates a delay time between a transmission signal and a reception signal, which is set based on the distance between an object and the lidar apparatus. 
       FIGS. 9A and 9B  are views showing the relationship between the frequency of a transmission signal and the frequency of a reception signal and a beat frequency acquired therefrom on a time axis.  FIG. 9A  shows the same static situation as in  FIG. 8A , and  FIG. 9B  shows the same dynamic situation as in  FIG. 8B . The beat frequency f b  is the difference between the transmission frequency and the reception frequency. 
     In the static situation shown in  FIG. 9A , the beat frequency may be set based on a delay time due to the distance between the object and the lidar apparatus. 
     In the dynamic situation shown in  FIG. 9B , the relative speed between the object and the lidar apparatus is changed, with the result that a Doppler frequency shift phenomenon occurs. Consequently, the beat frequency is a combination of a range beat frequency f r  and a Doppler frequency f d . 
     The beat frequency includes an up-beat frequency, which corresponds to an up chirp, and a down-beat frequency, which corresponds to a down chirp. 
     The up-beat frequency and the down-beat frequency each include a frequency shift component caused due to the distance to a target that is moving and the speed relative to the target. These components are referred to as a range beat frequency and a Doppler frequency. 
     The up-beat frequency may be expressed as the sum of the range beat frequency and the Doppler frequency, and the down-beat frequency may be expressed as the difference between the range beat frequency and the Doppler frequency. 
     A Doppler frequency having a negative value may correspond to a scenario in which the object is approaching the lidar apparatus  400 , and a Doppler frequency having a positive value may correspond to a scenario in which the object is moving away from the lidar apparatus  400 . 
     The processing unit  474  of the processor  470  may calculate the distance to the object and the speed relative to the object based on the range beat frequency and the Doppler frequency. 
     Referring back to  FIG. 4 , the DAC unit  477  may be configured to convert a digital signal into an analog signal. The converted analog signal may be input to the waveform generator  411 . 
     In some implementations, the lidar apparatus  400  may further include an optical splitter  510 , an optical guide unit  520 , an optical steering unit  530 , and a lens  540 . 
     The optical splitter  510  may be configured to split transmission light into a plurality of split beams. 
     The optical guide unit  520  may be disposed between the optical generation unit  417  and the optical steering unit  530 . The optical guide unit  520  may guide the transmission light, output by the optical generation unit  417 , to the optical steering unit  530 . 
     The optical guide unit  520  may include a core, made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ), having a cladding structure. 
     The optical guide unit  520  may include a plurality of cores. Each of the cores may be made of, for example, silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ), and may have a cladding structure. 
     The optical guide unit  520  may guide the plurality of beams that are split by the optical splitter  510  towards the optical steering unit  530  through the cores of the optical guide unit  520 . 
     The optical guide unit  520  may guide the reflection light towards the photo detector  421 . 
     The optical steering unit  530  may steer transmission light. The optical steering unit  530  may perform beam steering by outputting light, the optical phase of which has been changed by the heater  482  or the piezoelectric unit  484 . 
     The lens  540  may change the path of light steered by the optical steering unit  530 . The lens  540  may set the field of view (FOV) of the lidar apparatus  400  based on the refractive index thereof. 
       FIG. 5  is a reference block diagram illustrating transmission light and reception light according to some implementations. 
     Referring to  FIG. 5 , laser light that is generated by the optical generation unit  417  may be input into the optical splitter  510 . 
     The optical splitter  510  may split the laser light into a plurality of beams. The split beams of the laser light may be guided by the optical guide unit  520 , and may be input into the optical steering unit  530 . 
     In some implementations, the optical splitter  510  may change the phases of the split beams of the laser light. The phase-changed beams of the laser light may be provided to the optical steering unit  530 . 
     The optical guide unit  520  may include a plurality of cores. Each of the cores may be made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ), and may have a cladding structure. 
     The heater  482  (see  FIG. 3 ) may provide heat to the optical guide unit  520 . The optical phases of the beams guided by the optical guide unit  520  may be changed by the heat provided from the heater  482 . For example, the refractive index of the optical guide unit  520  may be changed by the heat provided from the heater  482 , and the optical phases of the beams guided by the optical guide unit  520  may be changed by the changed refractive index of the optical guide unit  520 . 
     The processor  470  may control the heater  482  such that the optical phases of the beams guided by the optical guide unit  520  are changed. 
     In some implementations, a piezoelectric unit (e.g., piezoelectric unit  484  of  FIG. 3 ) may apply pressure to the optical guide unit  520 . The optical phases of the beams guided by the optical guide unit  520  may be changed by the pressure applied from the piezoelectric unit  484 . For example, the refractive index of the optical guide unit  520  may be changed by the pressure applied from the piezoelectric unit  484 , and the optical phases of the beams guided by the optical guide unit  520  may be changed by the changed refractive index of the optical guide unit  520 . 
     The processor  470  may control the piezoelectric unit  484  such that the optical phases of the beams guided by the optical guide unit  520  are changed. 
     In some implementations, the optical phases of the beams may be changed differently. The optical phase-changed beams may be introduced into the optical steering unit  530 . The optical steering unit  530  may condense the beams introduced thereinto. If the beams have different optical phases, then the condensed beams may be differently steered based on the respective optical phases of the beams. 
     The light steered by the optical steering unit  530  may be output to the lens  540 . 
     The light passes through the lens  540 , is output, and is then reflected by an object O. The light reflected by the object O may be introduced into the photo detector  421  via the optical steering unit  530  and the optical guide unit  520 . 
     The processor  470  may steer the light output from the optical steering unit  530  through the heater  482  or the piezoelectric unit  484 . 
       FIG. 6A  is a reference view illustrating an optical guide unit according to some implementations.  FIG. 6B  is a reference view illustrating some effects and features of the optical guide unit according to some implementations. 
       FIG. 6A  shows an example in which the optical guide unit  520  includes a single core  525 . Alternatively, the optical guide unit  520  may include a plurality of cores, as previously described. 
     Referring to  FIG. 6A , the optical guide unit  520  may include a substrate  521 , a first silicon dioxide layer  522  formed on the substrate  521 , a second silicon dioxide layer  523  formed on the first silicon dioxide layer  522 , a core  525  formed in the second silicon dioxide layer  523 , and a third silicon dioxide layer  524  formed on the second silicon dioxide layer  523 . 
     The substrate  521  may be a silicon substrate, as an example. 
     The first silicon dioxide layer  522  may be a thermal silicon dioxide (SiO 2 ) layer. 
     The second silicon dioxide layer  523  may be a low pressure chemical vapor deposition (LPCVD) silicon dioxide (SiO 2 ) layer. 
     The core  525  may be formed in the second silicon dioxide layer  523 . The core  525  may be made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ), and may have a cladding structure. 
     The third silicon dioxide layer  524  may be a plasma enhanced chemical vapor deposition (PECVD) silicon dioxide (SiO 2 ) layer. 
       FIG. 6B  shows examples of experimental results with respect to the bending radius, attenuation, applicable beam wavelength, and fiber-chip coupling when the core is made of various kinds of materials. 
     Referring to  FIG. 6B , in the case in which the core  525  (see  FIG. 6A ) is made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ) and has a cladding structure, the bending radius of the core  525  may be 0.05 mm. The smaller the bending radius of the core  525  is, the more the optical guide unit may be miniaturized and integrated. In the case in which the core  525  is made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ) and has a cladding structure, the core  525  may be miniaturized and integrated more than cores made of other different materials. 
     In the case in which the core  525  is made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ) and has a cladding structure, the loss ratio of the core  525  per unit length (cm) is 0.05 dB, which is lower than the loss ratios of cores made of other different materials. Since the loss ratio of the core  525  is low in the case in which the core  525  is made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ) and has a cladding structure, the optical generation unit may be configured using a light source having a small output. In addition, the core  525  may have high energy efficiency. 
     In the case in which the core  525  is made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ) and has a cladding structure, light ranging from visible light to infrared light may be used as transmission light. Visible light from the lidar apparatus must not be introduced into the eyes of a pedestrian or a driver of a nearby vehicle. For this reason, the core  525  made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ) and having a cladding structure is used to emit infrared light, the wavelength of which is long. 
     In the case in which the core  525  is made of silicon nitride (Si 3 N 4 ) and silicon dioxide (SiO 2 ) and has a cladding structure, the characteristics of coupling between a chip and a fiber array are excellent. 
       FIGS. 10A and 10B  are diagrams illustrating examples of an optical steering unit (e.g., optical steering unit  530  in  FIG. 5 ) according to an implementation. 
     As shown in  FIG. 10A , an optical steering unit may include an optical phased array  1010 , which may include a plurality of individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d . The individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d  may be formed, for example, by using silicon photonics. 
     The optical phased array  1010  may be configured to output a plurality of beams that were split by an optical splitter (e.g., optical splitter  510  in  FIG. 5 ). For example, the optical phased array  1010  may output the plurality of beams in a state in which the phases of the beams have been changed. 
     The beams that have been split (e.g., by optical splitter  510 ) may be introduced into the individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d.    
     The processor  570  may apply an electrical signal to the optical phased array  1010  in order to adjust the optical phase of each of the individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d.    
     For example, the processor  470  may apply a specific electrical signal to each of the individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d . In this case, the emission direction of the output beams may be changed. The output beams may be referred to as transmission light. 
     The processor  470  may change the electrical signal applied to the optical phased array  1010 . In this case, the emission angle of the output beams may be changed. 
     For example, when the electrical signal applied to the optical phased array  1010  is changed under the control of the processor  470 , the emission angle of the output light is also changed. As such, the processor  470  may adaptively control the emission angle of the output light by controlling the electrical signal applied to the optical phased array  1010 . 
     The maximum value of the changed emission angle corresponds to the field of view (FOV) of detection. As such, the processor  470  may adjust the electrical signal applied to the optical phased array  1010  in order to vary the field of view (FOV) of the output light. 
     For example, the optical splitter  510  may split the light generated by the optical generation unit  417 , and may change the phases of the split beams. The beams that are split by the optical splitter  510  and phase-changed may be introduced into the individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d . The processor  470  may control the optical splitter  510  such that the emission angle of the beams output from the optical steering unit  530  is adjusted. 
     Referring to  FIG. 10A , when the phases of the beams incident on the individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d  are changed, a wavefront, which represents an interconnection of beams having the same phase, is bent. Since the advancing direction of the beams is perpendicular to the wavefront, the advancing direction of the beams is refracted at a predetermined angle. When the phase delay value of the beams introduced into the individual arrays  1010   a ,  1010   b ,  1010   c , and  1010   d  is changed, the refracted angle of the beams may be changed as represented in Equation 1. 
     For example, the emission angle of the beams that are output from the optical steering unit  530  may be represented as in Equation 1, below. 
     
       
         
           
             
               
                 
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                       2 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   1 
                 
               
             
           
         
       
     
     Where “N” indicates the number of individual arrays, “a” indicates the size of each of the individual arrays, indicates the distance between the individual arrays, “Φ” indicates a phase delay, “λ” indicates the wavelength of light, “θ” indicates the emission angle, “I 0 ” indicates a peak intensity, and “I” indicates an intensity in the  0  direction. 
       FIG. 10B  shows the intensity of the steered beams depending on the phase delay on the assumption that N=100, a=λ/2, and d=λ/2. 
     As shown in  FIG. 10B , the intensity of light at a desired angle is increased as the phase delay value is changed, whereby the beams are steered. When the steering angle is increased, the intensity of the output light decreases. 
     Reference numeral  1051  indicates the case in which the phase delay angle is 0 degrees, reference numeral  1052  indicates the case in which the phase delay angle is 40 degrees, and reference numeral  1053  indicates the case in which the phase delay angle is 70 degrees. 
       FIGS. 11A to 11C  are reference views illustrating an optical steering unit according to another implementation. 
     Referring to  FIG. 11A , the lidar apparatus  400  may further include a lens  1120 . 
     The optical steering unit  530  may include an optical switch  1110 . For example, the optical switch  1110  may be arrayed waveguide grating (AWG). 
     The optical switch  1110  is an optical device that selects the path of advancement of light based on an electrical signal applied by the processor  470 . 
     The processor  470  may control the optical switch  1110  so as to adjust the path of light. The processor  470  may provide an electrical signal to the optical switch  1110 . The optical switch  1110  may enable light to be emitted from a predetermined point (one of the points  1110   a  to  1110   g ) located in front of the lens  1120  based on the electrical signal provided by the processor  470 . Since the point from which the light is emitted is changed depending upon the electrical signal applied to the optical switch  1110 , the path of advancement of the beam output through the lens  1120  is changed. The processor  470  may change the electrical signal applied to the optical switch  1110  so as to steer the output beam. The steering change value may be changed so as to change the field of view. Meanwhile, the output beam may be referred to as transmission light. 
     Referring to  FIG. 11B , the emission angle of the beam through the optical switch  1110  may be acquired as represented in Equation 2. 
     
       
         
           
             
               
                 
                   θ 
                   = 
                   
                     
                       tan 
                       
                         - 
                         1 
                       
                     
                     ⁡ 
                     
                       ( 
                       
                         
                           Δ 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           x 
                         
                         f 
                       
                       ) 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   2 
                 
               
             
           
         
       
     
     Where Δx indicates the change in position of a light emission point through the optical switch  1110 , f indicates the focal distance of the lens  1120 , and θ indicates an emission angle. 
     Referring to  FIG. 11C , in the case in which the focal distance f of the lens  1120  is 5.0 mm, the emission angle θ is changed depending on the change Ax in position of the light emission point, as shown in the graph. 
     The examples described above may be implemented as code that can be written on a computer-readable medium in which a program is recorded and thus read by a computer. The computer-readable medium includes all kinds of recording devices in which data is stored in a computer-readable manner. Examples of the computer-readable recording medium may include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a read only memory (ROM), a random access memory (RAM), a compact disk read only memory (CD-ROM), a magnetic tape, a floppy disc, and an optical data storage device. In addition, the computer-readable medium may be implemented as a carrier wave (e.g., data transmission over the Internet). In addition, the computer may include a processor or a controller. Thus, the above detailed description should not be construed as being limited to the implementations set forth herein in all terms, but should be considered by way of example. The scope of the present disclosure should be determined by the reasonable interpretation of the accompanying claims and all changes in the equivalent range of the present disclosure are intended to be included in the scope of the present disclosure. 
     Although some examples have been described with reference to a number of illustrative implementations thereof, other modifications and implementations may fall within the spirit and scope of this disclosure. For example, variations and modifications may be made 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, alternatives uses may also be made.