Liquid Crystal-Based Optical Deflector and Optical Scanner Using the Liquid Crystal-Based Optical Deflector

Abstract

The present invention relates to a liquid crystal-based optical deflector and an optical scanner using the liquid crystal-based optical deflector. The liquid crystal-based optical deflector includes: a light source array, an optical deflector, an optical component, and a controller. The light source array is configured to generate laser beams; the optical deflector includes a plurality of liquid crystal cells that transmit the laser beams, and the optical deflector is configured to deflect the transmission path of the laser beams according to a gradually increasing voltage distribution applied to the plurality of liquid crystal cells; the optical component is configured to scan the laser beams deflected by the optical deflector in a horizontal direction; and the controller is configured to adjust the voltage distribution applied to the plurality of liquid crystal cells.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10 - 2019 - 0130198, filed on October 18, 2019, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical field

[0003] The present invention relates to a liquid - crystal - based optical deflector and an optical scanner using the liquid - crystal - based optical deflector. Background art

[0004] Light Detection and Ranging (LiDAR) that measures distance using a laser has been applied to autonomous vehicles, and LiDAR has been recognized as a core technology for operating autonomous vehicles. The LiDAR sensor applied to a vehicle can support autonomous driving and avoid collisions by measuring the distance to another vehicle, a pedestrian, or an obstacle around the vehicle in motion.

[0005] The LiDAR sensor includes: a laser emitter, a laser detector (or a laser receiver), and a processor; the laser emitter emits a laser beam; the laser detector (or the laser receiver) receives (detects) the laser beam that is emitted from the laser emitter and reflected by an object and then returns; the processor calculates the distance between the LiDAR sensor and the object by using the laser beam received through the laser detector. When measuring the distance through the LiDAR sensor, the laser emitter scans the laser beam in one direction by using a motor or a micromirror. This commonly used beam - scanning technology has limitations in terms of operation speed, stability, and durability. Summary of the invention

[0006] One aspect of the present invention provides a liquid - crystal - based optical deflector and an optical scanner using the optical deflector, which can perform beam scanning by electric control by using the electro - optical characteristics of liquid crystal without mechanical drive.

[0007] Another aspect of the present invention provides an optical scanner employing at least two optical deflectors, which can compensate for light loss caused by the electro - optical characteristics of the optical deflector and can output light uniformly.

[0008] According to one aspect of the present invention, an optical deflector includes: a first substrate and a second substrate, a plurality of liquid crystal cells, a first partition wall electrode and a second partition wall electrode, a first electrode array, a second electrode array, a first external connector, and a second external connector, wherein the first substrate and the second substrate are arranged opposite to each other; the plurality of liquid crystal cells are formed between the first substrate and the second substrate and are separated by partition walls; the first partition wall electrode and the second partition wall electrode are respectively formed on the surfaces of the inner partition walls in each liquid crystal cell; the first electrode array has a plurality of electrodes regularly arranged on the first substrate inside each liquid crystal cell; the second electrode array is arranged on the second substrate in each liquid crystal cell symmetrically with respect to the first electrode array; the first external connector is formed on the first substrate to connect the first partition wall electrode, the second partition wall electrode, and the first electrode array to the outside; and the second external connector is formed on the second substrate to connect the second electrode array to the outside.

[0009] Anti-reflection coatings are respectively formed on the outer surfaces of the first substrate and the second substrate.

[0010] An anti-reflection coating is formed on one of the outer surfaces of the first substrate and the second substrate, and a reflective coating is formed on the other outer surface of the first substrate and the second substrate.

[0011] According to another aspect of the present invention, an optical scanner includes: a light source array, an optical deflector, an optical instrument, and a controller, wherein the light source array generates laser beams; the optical deflector includes a plurality of liquid crystal cells that transmit the laser beams, and the optical deflector is configured to deflect the transmission paths of the laser beams according to the voltages applied to the plurality of liquid crystal cells; the optical instrument is configured to scan the laser beams deflected by the optical deflector in the horizontal direction; and the controller is configured to adjust the voltages applied to the plurality of liquid crystal cells.

[0012] The light source array includes a plurality of laser light sources arranged in the vertical direction.

[0013] The light source array emits beams collimated by a collimating lens.

[0014] Each liquid crystal cell includes: a first partition wall electrode and a second partition wall electrode, a first electrode array, and a second electrode array, wherein the first partition wall electrode and the second partition wall electrode are formed on the surfaces of the partition walls separating the liquid crystal cells; the first electrode array includes electrodes formed on the first substrate and arranged at a predetermined interval; and the second electrode array is formed on the second substrate symmetrically with respect to the first electrode array.

[0015] The controller applies a gradually changing voltage to the electrodes of the first electrode array, and gradually increases the voltage from the first partition electrode to the second partition electrode, and applies the same gradually changing voltage to the electrodes of the second electrode array that are symmetric to the electrodes of the first electrode array.

[0016] The controller applies a preset minimum voltage to one of the first partition electrode and the second partition electrode, and applies a preset maximum voltage to the other of the first partition electrode and the second partition electrode.

[0017] The controller adjusts the deflection angle of the laser beam incident on the optical deflector by adjusting the maximum voltage.

[0018] The optical scanner further includes at least one light source array and at least one optical deflector.

[0019] When the optical deflector is of the transmissive type, the optical deflector is located between the light source array and the optical instrument.

[0020] When the optical deflector is of the reflective type, the light source array and the optical instrument are located on one side of the optical deflector. Description of the Drawings

[0021] The above and other objects, features, and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings:

[0022] Figure 1 To show an exploded perspective view of an optical deflector according to an embodiment of the present invention;

[0023] Figure 2 To show a schematic diagram of the components of an optical deflector according to an embodiment of the present invention;

[0024] Figure 3 To show a schematic diagram of the operation of an optical deflector according to an embodiment of the present invention;

[0025] Figure 4 To show a cross-sectional view of a liquid crystal cell in an optical deflector according to an embodiment of the present invention;

[0026] Figure 5 To show Figure 1 A cross-sectional view of the optical deflector shown in

[0027] Figure 6A To show a schematic diagram of the voltage distribution in a liquid crystal cell of an optical deflector according to an embodiment of the present invention;

[0028] Figure 6B To show a schematic diagram of the electric field distribution in a liquid crystal cell of an optical deflector according to an embodiment of the present invention;

[0029] Figure 6C Schematic diagram showing the refractive index change in the liquid crystal cell of the optical deflector according to an embodiment of the present invention;

[0030] Figures 7A to 7C Schematic diagram showing the operating characteristics of the optical deflector according to an embodiment of the present invention;

[0031] Figure 8 Block diagram showing the optical scanner according to an embodiment of the present invention;

[0032] Figure 9 To show Figure 8 Schematic diagram showing the structure of the optical instrument shown in

[0033] Figure 10 and Figure 11 Schematic diagram showing the design change for expanding the scanning range of the optical scanner according to an embodiment of the present invention;

[0034] Figure 12 Schematic diagram showing the optical deflector according to another embodiment of the present invention;

[0035] Figure 13 To show Figure 12 Operating schematic diagram of the optical deflector shown in

[0036] Figure 14 and Figure 15 Schematic diagram showing the optical scanner using the optical deflector according to another embodiment of the present invention;

[0037] Figure 16 Schematic diagram showing the optical deflector according to yet another embodiment of the present invention;

[0038] Figure 17 To show Figure 16 Operating schematic diagram of the optical deflector shown in Detailed Description

[0039] It should be understood that the term "vehicle" or "vehicular" or other similar terms used herein generally include motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, boats including various boats and ships, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-petroleum energy sources). As used herein, a hybrid vehicle is a vehicle having two or more power sources, e.g., a vehicle having both gasoline power and electric power.

[0040] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should be further understood that when the terms "comprises" and / or "comprising" are used in this specification, it indicates the presence of the stated features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Throughout the specification, unless explicitly stated to the contrary, the terms "comprises" and variations such as "comprising" or "comprised of" should be understood to imply the inclusion of the stated element but not the exclusion of any other element. In addition, the terms "unit", "device", "component" and "module" described in the specification represent a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0041] In addition, the control logic of the present invention can be implemented as a non-transitory computer-readable medium on a computer-readable medium, which contains executable program instructions executed by a processor, a controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage devices. The computer-readable medium can also be distributed over network-connected computer systems so that the computer-readable medium is stored and executed in a distributed manner, for example, by a telematics server or a controller area network (CAN).

[0042] Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings. When adding reference numerals to the components of each drawing, it should be noted that even if the same or equivalent components are shown in other drawings, they are denoted by the same reference numerals. Additionally, in the following description of the embodiments of the present invention, detailed descriptions of well-known features or functions will be excluded so as not to unnecessarily obscure the gist of the present invention.

[0043] When describing components according to embodiments of the present invention, terms such as first, second, "A", "B", (a), (b), etc. may be used. These terms are only intended to distinguish one component from another component, and these terms do not limit the nature, order or sequence of the components. Additionally, unless otherwise defined, all terms used herein, including technical terms or scientific terms, have the same meaning as those commonly understood by those skilled in the art to which the present invention pertains. Such terms defined in a general dictionary should be interpreted as having the same meaning as the contextual meaning in the relevant technical field, and should not be interpreted as having an ideal or overly formal meaning, unless clearly defined in the present application.

[0044] The present invention utilizes a light deflector (beam scanner) based on a liquid crystal material, which can be driven at a lower voltage and lower power while generating excellent light scanning efficiency. Specifically, a light scanner that supports long-distance observation and high-speed measurement functions is required to apply the light deflector to a vehicle. Therefore, the present invention provides a liquid crystal-based light deflector, which shows a faster operation speed and easier scalability compared to traditional mechanical light deflectors.

[0045] Figure 1 To show an exploded perspective view of the light deflector according to an embodiment of the present invention, Figure 2 To show a schematic diagram of the components of the light deflector according to an embodiment of the present invention, Figure 3 To show a schematic working diagram of the light deflector according to an embodiment of the present invention, Figure 4 To show a cross-sectional view of the liquid crystal cell in the light deflector according to an embodiment of the present invention, Figure 5 To show Figure 1 a cross-sectional view of the light deflector shown in

[0046] As Figures 1 to 10 shown, the light deflector 100 includes: a first substrate 110, a second substrate 120, a sealing member 130, an alignment hole 140, and an alignment member 150.

[0047] The first substrate 110 and the second substrate 120 are arranged opposite to each other and are substrates (transparent substrates) formed of glass, silicon nitride (SiN), or silicon oxynitride (SiNO). A plurality of liquid crystal cells 112 are formed between the first substrate 110 and the second substrate 120 and are separated by partition walls 111.

[0048] As Figure 4As shown, in order to form a plurality of liquid crystal cells 112, an exposure process and an etching process are performed on the first surface (top surface) of the first substrate 110 using a mask to repeatedly form grooves 112 at a predetermined interval. Each groove 112 has a width 81 of about 5 μm to 20 μm and a depth 82 of about 15 μm to 50 μm. In this case, the partition walls 111 are formed between the grooves 112 (liquid crystal cells to be described later) to have a thickness of several micrometers (e.g., 1 μm - 2 μm) or less. The size of the width (area) of the groove 112 can be in the range of about 5 μm to 20 μm, and the number of grooves to be repeated can be adjusted according to the size of the beam spot of the light source beam (i.e., the laser beam).

[0049] The first substrate 110 having the grooves 112 is thinly coated with a transparent material such as indium tin oxide (ITO) by deposition or spin coating. Thereafter, an exposure and an etching process are performed on the resulting structure using a mask to form electrodes (i.e., the first electrode array 113) on the bottom surface of the groove 112, which has a periodic interval 84 with a width of about 0.05 μm - 1 μm and a length of about 0.1 μm - 2 μm. In other words, the first electrode array 113 is formed on the first substrate 110 inside the liquid crystal cell 112 such that the distance between the electrodes is half of the periodic interval 84.

[0050] In addition, ITO thin films coated on the surfaces of the walls of the groove (i.e., the surfaces of the partition walls 111) are formed into electrodes 111a and 111b. In other words, the first partition wall electrode 111a and the second partition wall electrode 111b are formed on the first partition wall surface and the second partition wall surface facing the inside of the liquid crystal cell 112, respectively. The first partition wall electrode 111a and the second partition wall electrode 111b allow the formation of a refractive index distribution with an ideal sawtooth shape inside the liquid crystal cell 112.

[0051] The first external connector 114 is formed on the first surface (top surface) of the first substrate 110. The first external connector 114 connects the first electrode array 113, the first partition wall electrode 111a, and the second partition wall electrode 111b to an external circuit. For example, the first external connector 114 electrically connects the light deflector 100 to a controller 230 to be described later. The first electrode array 113, the first partition wall electrode 111a, and the second partition wall electrode 111b extend to the first external connector 114.

[0052] The first surface (bottom surface) of the second substrate 120 is coated with a transparent material such as ITO, and then the second electrode array 123 is formed at a position symmetric to the position of the first electrode array 113 formed on the bottom surface of the groove of the first substrate 110. The second electrode array 123 has the same electrode width and the same periodicity as the first electrode array 113. The second external connector 124 is formed on the first surface of the second substrate 120 and extends such that the second electrode array 123 is connected to the outside.

[0053] After electrodes are formed on the first substrate 110 and the second substrate 120, the entire surfaces of the two substrates with electrodes are coated with an alignment material such as polyimide, and then heat treatment is performed. Next, the alignment material (e.g., polyimide) is removed from the surface of the groove wall of the first substrate 110 (i.e., the partition wall 111).

[0054] Using the alignment holes 140 formed in the first substrate 110 and the second substrate 120, the first electrode array 113 and the second electrode array 123 formed on the first substrate 110 and the second substrate 120 respectively are aligned to be symmetric with each other with respect to the x-z plane. In this case, the first substrate 110 and the second substrate 120 can be aligned by inserting the alignment member 150 into the alignment holes 140. The first substrate 110 and the second substrate 120 are aligned and bonded to each other using an adhesive, thereby completing the assembly of the first substrate 110 and the second substrate 120. For example, referring to Figure 5 , opposite ends of the top surface 118 of the first substrate 110 are bonded to opposite ends of the bottom surface 128 of the second substrate 120 such that the first substrate 110 and the second substrate 120 are assembled.

[0055] Liquid crystal is injected into the groove, that is, into the liquid crystal cell 112 between the assembled first substrate 110 and the second substrate 120. In this case, ultrasonic waves or sound waves can be applied to the liquid crystal cell 112 such that the liquid crystal is uniformly filled in the liquid crystal cell 112. When the liquid crystal is completely injected into the liquid crystal cell 112, a sealing member 130 including Mylar, vinyl, or Teflon is used to seal the liquid crystal injection holes formed on the sides of the liquid crystal cell 112. After arranging the sealing member 130 to seal the liquid crystal injection holes and prevent the first external connector 114 (i.e., the first external connector array) from being covered, sealing is performed using an adhesive to prevent the liquid crystal from flowing out of the assembly.

[0056] Thereafter, heat treatment or ultraviolet treatment is performed based on the liquid crystal material such that the directions of the liquid crystal molecules between the first substrate 110 and the second substrate 120 are aligned, thereby completing the transparent liquid crystal-based light deflector 100.

[0057] By gradually increasing the voltage from one wall side to the other wall side within each liquid crystal cell, the adjusted voltage is applied to the first external connector 114 (first external electrode array) and the second external connector 124 (second external electrode) of the optical deflector 100, such that the refractive index distribution of the internal liquid crystal gradually changes, and the same voltage pattern is periodically repeated in each cell. The light beam (incident beam, IB) vertically incident on the transparent windows (liquid crystal cells) of the first substrate 110 and the second substrate 120 changes its diffraction angle according to the voltage applied to the plurality of liquid crystal cells 112 while passing through the liquid crystal cell 112. Therefore, as Figure 3 shown, the irradiation direction of the transmitted beam (transmission beam, TB) passing through the liquid crystal cell 112 can be changed. In other words, the irradiation direction (transmission optical path) of the light beam passing through the liquid crystal cell 112 can be adjusted by adjusting the voltage applied to the liquid crystal cell 112.

[0058] When the optical deflector 100 is of the transmissive type, antireflection coatings are applied on the second surface (bottom surface) of the first substrate 110 and the second surface (top surface) of the second substrate 120, thereby forming antireflection coatings 115 and 125. Meanwhile, when the optical deflector 100 is of the reflective type, a high-reflection coating is applied on either the second surface of the first substrate 110 or the second surface of the second substrate 120.

[0059] Figure 6A Schematic diagram showing the voltage distribution in the liquid crystal cell of the optical deflector according to an embodiment of the present invention; Figure 6B Schematic diagram showing the electric field distribution in the liquid crystal cell of the optical deflector according to an embodiment of the present invention; Figure 6C Schematic diagram showing the refractive index change in the liquid crystal cell of the optical deflector according to an embodiment of the present invention. Hereinafter, an exemplary demonstration case according to this embodiment of the optical deflector 100 shows that the beam deflection angle of the incident light beam is 8°.

[0060] A preset minimum voltage is applied to the first partition wall electrode 111a in each liquid crystal cell 112, and a preset maximum voltage is applied to the second partition wall electrode 111b in the liquid crystal cell 112. The same voltage is applied to the symmetric electrodes between the first electrode array 113 and the second electrode array 123 in each liquid crystal cell 112. In this case, the applied voltage increases sequentially from the electrode adjacent to the first partition wall electrode 111a to the electrode adjacent to the second partition wall electrode 111b. In this case, the maximum voltage is determined according to the required diffraction angle. For the case where the maximum voltage is applied such that the incident light beam is deflected by 8°, the voltage distribution in the plurality of liquid crystal cells 112 is in Figure 6AAs shown, the electric field distribution in the corresponding plurality of liquid crystal cells 112 is as Figure 6B shown. As Figure 6A and Figure 6B shown, the voltage and electric field distribution in each liquid crystal cell 112 has a sawtooth shape, which can improve the diffraction efficiency.

[0061] When using liquid crystals that can be vertically aligned, in the case where no voltage is applied to the liquid crystal cells 112, the liquid crystals are vertically aligned between the first substrate 110 and the second substrate 120. Then, a gradually varying voltage distribution is applied to the liquid crystal cells 112 to form an electric field distribution as Figure 6B shown inside the liquid crystal cells, which results in a horizontally aligned liquid crystal distribution and finally forms a refractive index distribution as Figure 6C shown. The length of the liquid crystal cells 112 in the y-axis direction (corresponding to the z-axis in Figure 1 and Figure 12 ) can be determined according to the size of the incident light beam, and the cell size in the x-axis direction can be adjusted by increasing or decreasing the number of liquid crystal cells 112 to match the beam size.

[0062] Figures 7A to 7C is a schematic diagram showing the operating characteristics of an optical deflector for an exemplary case according to an embodiment of the present invention.

[0063] According to the simulation results of the finite-difference time-domain method (FDTD) for the case where a light beam vertically incident on the optical deflector 100 is deflected by 2°, 5°, and 10° through the liquid crystal cells 112, the near-field electric field distribution of the deflected light beam after passing through the liquid crystal cells 112 is shown in Figure 7A .

[0064] According to the simulation results for the case where the diffraction angle of the light beam deflected by the optical deflector 100 is 8°, the far-field light beam intensity distribution from the optical deflector 100 is shown in Figure 7B .

[0065] When adjusting the deflection angle of the light beam by adjusting the voltage applied to the liquid crystal cells of the optical deflector 100, Figure 7C shows the relationship between the relative beam intensity (i.e., diffraction efficiency) of the far-field deflected light beam compared to the beam intensity when vertically incident and the beam deflection angle.

[0066] Figure 8 is a block diagram showing an optical scanner according to an embodiment of the present invention, Figure 9 is a schematic diagram showing the structure of the optical instrument shown in Figure 8 . The optical scanner is a device (laser beam emitter) that emits laser beams in a LiDAR sensor.

[0067] Refer to Figure 8, the light scanner 200 emits a laser beam and projects the laser beam onto an object. The light scanner 200 includes: a light source array 210, a light deflector (beam deflector) 100, an optical component 220, and a controller 230.

[0068] The light source array 210 is a multi-channel laser beam source array formed by vertically arranging at least one laser beam source to emit a laser beam. The laser light source may include a laser diode. The light source array 210 can emit a beam collimated by a collimating lens.

[0069] The light deflector 100 changes (deflects) the irradiation direction of the laser beam emitted from the light source array 210. In other words, the light deflector 100 refracts the multi-channel laser light source beam emitted from the light source array 210 in the horizontal direction. Under the control of the controller 230, the light deflector 100 scans the laser beam from the light source array 210 in any one horizontal direction (for example, the direction from left to right).

[0070] The light deflector 100 includes a plurality of liquid crystal cells 112 separated (divided) by partition walls 111. A first partition wall electrode 111a and a second partition wall electrode 111b are formed on the inner partition wall 111 of each liquid crystal cell 112. In addition, a first electrode array 113 is formed on the bottom surface of each liquid crystal cell 112 such that the electrodes are arranged at a predetermined pitch, and a second electrode array 123 is formed on the top surface opposite to the bottom surface to be symmetric with the electrodes of the first electrode array 113.

[0071] The optical component 220 supports the vertical irradiation range of the laser beam deflected by the light deflector 100 in the horizontal direction. Refer to Figure 9 , the optical component 220 uses the multi-channel laser beam emitted from the light source array 210 to cover the vertical field of view (FoV) (i.e., the vertical illumination angle). In addition, the optical component 220 can use an ultra-wide-angle lens and / or a wide-angle lens to cover the horizontal field of view.

[0072] The controller 230 controls the operation of the optical scanner 200. Although not shown in the drawings, the controller 230 may include a memory and a processor. The memory may be implemented using at least one of the following storage media, for example, flash memory, a hard disk, a Secure Digital (SD) card, a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a Read Only Memory (ROM), a Programmable Read Only Memory (PROM), an Electrically Erasable Programmable ROM (EEPROM), an Erasable Programmable ROM (EPROM), a register, etc. The processor may include at least one of an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a Central Processing Unit (CPU), a microcontroller, and / or a microprocessor.

[0073] The controller 230 adjusts the deflection angle of the laser beam incident on the liquid crystal cells 112 by adjusting the voltage applied to the plurality of liquid crystal cells 112 in the optical deflector 100. The controller 230 applies a preset minimum voltage and a preset maximum voltage to the first partition wall electrode 111a and the second partition wall electrode 111b of each liquid crystal cell 112, respectively. In addition, the controller 230 applies a gradually changing voltage to the electrodes constituting the first electrode array 113 and the second electrode array 123 in each liquid crystal cell 112. In this case, the same voltage is applied to the symmetric electrode pairs of the first electrode array 113 and the second electrode array 123.

[0074] The LiDAR sensor receives the laser beam emitted from the optical scanner 200 and reflected from an object through a detector module. The detector module may provide reception information about the reception time of the laser beam or phase information of the laser beam to the signal processing unit of the LiDAR sensor. The signal processing unit calculates (measures) the distance between the optical scanner 200 and the object by processing the signals received from the optical scanner 200 and the detector module. The processing module collects transmission information (for example, information about the transmission time of the laser beam or phase information of the laser beam) from the optical scanner 200, and receives the reception information of the laser beam from the detector module. The processing module may measure the distance between the optical scanner 200 and the object based on the transmission information and the reception information of the laser beam. In this case, the processing module may calculate the distance by using the time of flight (TOF) method or the phase shift (PS) method. The TOF method measures the time taken from emitting the laser beam to collecting the beam reflected from the object, and calculates the distance to the object based on the measured time. The PS method calculates the distance by measuring the phase change between the emitted laser beam and the beam returned after being reflected from the object.

[0075] Figure 10 andFigure 11 A schematic diagram showing an exemplary design change for expanding the scanning range of an optical scanner according to an embodiment of the present invention.

[0076] Referring to Figure 10 and Figure 11 , the horizontal viewing angle of the optical scanner 200 can be expanded, and two or three optical deflectors 100 and a light source array 210 can be utilized to improve the uniformity of the beam intensity of the laser beam. In other words, the number of optical deflectors 100 and the number of light source arrays 210 in the optical scanner 200 are increased, thereby expanding the scanning range (beam irradiation range) and irradiating the laser beam with a uniform intensity.

[0077] As described above, the optical scanner 200 employs at least two optical deflectors 100 and at least two light source arrays 210, thereby expanding the irradiation range of the laser beam, compensating for the non-uniform intensity distribution of the diffracted beam caused by the reduction in diffraction efficiency when the deflection angle increases in the case of a single optical deflector 100, and ultimately providing a scanning beam with a relatively uniform and bright intensity distribution.

[0078] Figure 12 A schematic diagram showing an optical deflector 600 according to another embodiment of the present invention, Figure 13 is a schematic diagram showing the operation of the optical deflector shown in Figure 12 . In the following description of this embodiment, repeated descriptions of the same components as the optical deflector 100 shown in Figure 1 will be omitted.

[0079] Referring to Figure 12 , a reflective coating 610 is formed on the second surface (i.e., the bottom surface of the first substrate 110). The reflective coating 610 is formed by using a metal material or a mirror. The reflective coating 610 of the first substrate 110 reflects and diffracts the laser beam incident through the second substrate 120 of the optical deflector 600. As shown in Figure 13 , the optical deflector 600 outputs a beam 630, and the beam 630 deflects by adjusting the reflection angle of the incident beam 620 incident through the second substrate 120 according to the voltage applied to the liquid crystal cell 112.

[0080] Figure 14 and Figure 15 are schematic diagrams showing an optical scanner employing an optical deflector according to another embodiment of the present invention.

[0081] As shown in Figure 14 , when the optical deflector 600 shown in Figure 12 is applied to the optical scanner 200, the light source array 210 is arranged to face the second substrate 120 of the optical deflector 600. Additionally, as shown in Figure 15As shown, in order to expand the field of view of the optical scanner 200 and make the beam intensity uniform, at least two optical deflectors 600 and at least two light source arrays 210 can be adopted.

[0082] Figure 16 FIG. is a schematic diagram showing an optical deflector 900 according to another embodiment of the present invention. Figure 17 To show Figure 16 a working schematic diagram of the optical deflector 900 shown in. In the following description of this embodiment, repeated descriptions of the same components as the Figure 1 optical deflector 100 shown will be omitted. This embodiment proposes such a scheme: since the same voltage is applied to the symmetric electrodes through the electrical connection between the symmetric electrode pairs of the first substrate 110 and the relatively positioned second substrate 120, the number of external connectors of the optical deflector is reduced.

[0083] Referring to Figure 16 , in order to form the liquid crystal cells 112 on the first substrate 110, partition walls 111 for partitioning the liquid crystal cells 112 are formed on the first substrate 110 at regular intervals. A first electrode array 113 is formed on the bottom surface of each liquid crystal cell 112 (i.e., on the first substrate 110), and a second electrode array 123 is formed at a position symmetric to the first electrode array 113 on the top surface of the liquid crystal cell 112 (i.e., on the second substrate 120). In this case, a connector 901 extends from the first electrode array 113 to connect the first electrode array 113 on the first substrate 110 to the second electrode array 123 on the second substrate 120. Contact terminals 920 can be formed on the connector 901 to be electrically connected to the second external connector 124 of the second substrate 120.

[0084] Thereafter, a barrier wall 910 is formed on the opposite side of the liquid crystal injection hole of the liquid crystal cell 112. The barrier wall 910 includes a non-conductive material and has the same height as the partition wall 111. The barrier wall 910 can be formed by a selective thin film deposition process and an etching process.

[0085] According to the present invention, the deflection angle of the light beam can be adjusted by utilizing the electro-optical characteristics of the liquid crystal, so that the light beam scanning can be electrically controlled without mechanical drive.

[0086] In addition, according to the present invention, two or more optical deflectors are applied to compensate for the light loss caused by the electro-optical drive of the optical deflector, and uniform light output can be achieved.

[0087] Although the present invention has been described above with reference to exemplary embodiments and the accompanying drawings, the present invention is not limited thereto. It is obvious that those skilled in the art to which the present invention pertains can make various changes and modifications to the present invention in different ways without departing from the spirit and scope of the present invention provided by the appended claims. Therefore, the exemplary embodiments of the present invention are provided to explain the spirit and scope of the present invention, but not to limit them, such that the spirit and scope of the present invention are not limited by the embodiments. The scope of the present invention should be interpreted based on the appended claims, and all technical concepts within the scope equivalent to the claims should be included within the scope of the present invention.

Claims

1. An optical deflector, comprising: A first substrate and a second substrate, wherein the first substrate and the second substrate are arranged opposite to each other; A plurality of liquid crystal cells formed between the first substrate and the second substrate and separated by partition walls; A first partition wall electrode and a second partition wall electrode, wherein the first partition wall electrode and the second partition wall electrode are respectively formed on the surfaces of the inner partition walls in each liquid crystal cell; A first electrode array having a plurality of electrodes regularly arranged on the first substrate inside each liquid crystal cell; A second electrode array arranged symmetrically with the first electrode array on the second substrate in each liquid crystal cell; A first external connector array formed on the first substrate to connect the first partition wall electrode, the second partition wall electrode, and the first electrode array to the outside; And A second external connector array formed on the second substrate to connect the second electrode array to the outside.

2. The optical deflector according to claim 1, wherein, Anti-reflection coatings are respectively formed on the outer surfaces of the first substrate and the second substrate.

3. The optical deflector according to claim 1, wherein, An anti-reflection coating is formed on one of the outer surfaces of the first substrate and the second substrate, and a reflection coating is formed on the other outer surface of the first substrate and the second substrate.

4. An optical scanner, comprising: A light source array configured to generate laser beams; A light deflector including a plurality of liquid crystal cells that transmit laser beams, the light deflector being configured to deflect the transmission path of the laser beams according to the voltage applied to the plurality of liquid crystal cells; An optical component configured to scan the laser beams deflected by the light deflector in the horizontal direction; And A controller configured to adjust the voltage applied to the plurality of liquid crystal cells; Wherein each liquid crystal cell includes: A first partition wall electrode and a second partition wall electrode, the first partition wall electrode and the second partition wall electrode being formed on the surfaces of the partition walls separating each liquid crystal cell; A first electrode array including electrodes formed on the first substrate and arranged at a predetermined interval; and A second electrode array formed on the second substrate symmetrically with the first electrode array.

5. The optical scanner according to claim 4, wherein, The light source array includes a plurality of laser light sources arranged in the vertical direction.

6. The optical scanner according to claim 5, wherein, The light source array emits beams collimated by a collimating lens.

7. The optical scanner according to claim 4, wherein, The controller is configured to: Apply a gradually increasing voltage to the electrodes of the first electrode array in each liquid crystal cell; Apply the same gradually increasing voltage to the electrodes of the second electrode array symmetric with the electrodes of the first electrode array as the voltage applied to the electrodes of the first electrode array.

8. The optical scanner according to claim 7, wherein, The controller is configured to: Apply a preset minimum voltage to one of the first partition wall electrode and the second partition wall electrode; Apply a preset maximum voltage to the other of the first partition wall electrode and the second partition wall electrode.

9. The optical scanner according to claim 8, wherein, The controller is configured to: Adjust the deflection angle of the laser beams incident on the light deflector by adjusting the maximum voltage.

10. The optical scanner according to claim 4, further comprising: A plurality of light source arrays and a plurality of light deflectors.

11. The optical scanner according to claim 4, wherein, When the light deflector is of the transmission type, the light deflector is located between the light source array and the optical component.

12. The optical scanner according to claim 4, wherein, When the light deflector is of the reflection type, the light source array and the optical component are located on one side of the light deflector.

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