Patent Description:
There has been increasing interest in techniques of measuring a distance to an object or a direction thereof by using light (beams). In relation to this interest, research has been conducted on light sources which emit light and methods of steering a direction of light (beams) generated from such light sources or receiving light from a desired direction, that is, light scanning methods.

To perform scanning in a desired direction by using light, a method of mechanically rotating a light source or an optical element and a method of using interference of a bundle of light emitted from a plurality of unit cells or a plurality of waveguides by using an optical phased array (OPA) scheme have been generally used. In a method of mechanically rotating a light source, a motor or a microelectromechanical system (MEMS) mirror is used, and thus a volume may be large, and costs may increase. In an OPA scheme, a direction of light may be changed by electrically or thermally controlling unit cells or waveguides. Because an OPA scheme uses a plurality of waveguides, a total volume may be large, and an error may occur during modulation of a phase. In addition, a plurality of light sources are needed to transfer light to each of the waveguides.

The patent publication <CIT>discloses a LIDAR system comprising an omnidirectional conical mirror configured to reflect emitted laser light to a scene and to collect reflections onto an imaging pixel array configured to create a depth image of the scene.

Provided is a light detection and ranging (LIDAR) device for transmitting and receiving light without a motor.

Therein, the embodiments described in conjunction with <FIG> and <FIG> are embodiments according to the invention.

The remaining figures and their respective explanatory passages in the description describe illustrative examples that are unclaimed and thus not part of the invention.

In accordance with an aspect of the disclosure, there is provided a light detection and ranging (LIDAR) device according to claim <NUM>.

Advantageous embodiments are provided by the dependent claims.

Hereinafter, LIDAR devices according to embodiments of the disclosure will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements, and thus their repetitive description will be omitted.

The terms used in this specification are those general terms currently widely used in the art, but the terms may vary according to the intention of those of ordinary skill in the art, precedents, or new technology in the art. Also, specified terms may be selected by the applicant, and in this case, the detailed meaning thereof will be described in the detailed description. Thus, the terms used in the specification should be understood not as simple names but based on the meaning of the terms and the overall description.

Although terms, such as "first" and "second", can be used to describe various elements, the elements cannot be limited by the terms. The terms can be used to classify a certain element from another element.

<FIG> illustrates a LIDAR device <NUM> according to an embodiment. As shown in <FIG>, the LIDAR device <NUM> includes a light source <NUM> emitting first light L1, a light detector <NUM> configured to detect second light L2 that is a portion of the first light L1 reflected or scattered by an object <NUM> among the first light L1, a first reflector <NUM> omnidirectionally receiving the second light L2 and reflecting the second light L2 to the light detector <NUM>, and a processor <NUM> configured to acquire location information of the object <NUM> by using a detection result of the light detector <NUM>.

The light source <NUM> emits light. For example, the light source <NUM> may emit light in an infrared region. Using light in the infrared region may reduce or prevent the light in the infrared region from being mixed with natural light in a visible light region, including the sunlight. However, the light source <NUM> is not necessarily limited to emitting light in the infrared region and may emit light in various wavelength regions. When light in a wavelength region other than the infrared region is emitted by the light source <NUM>, correction for removing information of mixed natural light may be required.

The light source <NUM> may be a laser light source, but is not limited to particular examples. The light source <NUM> may be any one of an edge emitting laser, a vertical-cavity surface emitting laser (VCSEL), and a distributed feedback laser. For example, the light source <NUM> may be a laser diode.

The light detector <NUM> may convert the second light L2 reflected or scattered by the object <NUM> among the first light L1 into an electrical signal, e.g., a current. The first light L1 emitted from the light source <NUM> may be emitted on the object <NUM> and reflected or scattered by the object <NUM>. Light reflected or scattered by the object <NUM> among the first light L1 is the second light L2. The first light L1 and the second light L2 may have the same wavelength and different intensities.

The light detector <NUM> includes a plurality of pixels arranged in an array form. The plurality of pixels may be arranged in a matrix form. Each of the pixels, as a light-receiving element, may output an electrical signal corresponding to the second light L2, e.g., a current. A direction, a height, or the like of the object <NUM> may be determined based on a location of a pixel which has detected the second light L2 among the pixels.

Each of the pixels may be a light-receiving element operating in a state in which a bias voltage is applied thereto. For example, the light detector <NUM> may include an avalanche photo diode (APD) or a single photon avalanche diode (SPAD). The light detector <NUM> may have a circuit configuration of an analog front end (AFE), a time digital counter (TDC), and the like according to whether the light detector <NUM> includes the APD or the SPAD as a light-receiving element.

The light detector <NUM> may further include a current-voltage conversion circuit configured to convert the output current into a voltage and an amplifier configured to amplify an amplitude of the voltage. In addition, the light detector <NUM> may further include a lens condensing the second light L2 reflected or scattered by the object <NUM> and a filter, e.g., a high-pass filter, filtering an electrical signal of a certain frequency.

The first reflector <NUM> omnidirectionally receives the second light L2 and reflects the second light L2 to the light detector <NUM>. The first reflector <NUM> is symmetrical with reference to a central axis X. For example, the first reflector <NUM> may include at least one of a reverse-cone shape, an inverse hemispherical shape, or an inverse semielliptical shape. In addition, a cross-section of the first reflector <NUM> may include at least one of a circle, a polygon, or an ellipse. Although <FIG> shows the first reflector <NUM> of a reverse-cone shape, the first reflector <NUM> is not limited thereto.

A first reflective surface <NUM> having a tapered shape with a width gradually narrowing from an upper area to a lower area thereof is included on the outer circumferential surface of the first reflector <NUM>. The first reflective surface <NUM> may have an angle of inclination θ with respect to the central axis X. For example, the first reflective surface <NUM> may include an area having a constant angle of inclination with respect to the central axis X and include an area having a variable angle of inclination with respect to the central axis X. Although <FIG> shows that the angle of inclination θ of the first reflective surface <NUM> is constant, the angle of inclination θ is not limited thereto and may vary.

The first reflective surface <NUM> may be formed using a material having a relatively high refractive index. For example, the first reflective surface <NUM> may be formed using a white resin, a metal, a reflective paint, and the like of a relatively high refractive index. The white resin may include a white foam polyethylene terephthalate (PET) material, a white polycarbonate material, or the like. Reflectivity of these materials are about <NUM>%, and the reflection loss of light may be small, and thus, the reduction in efficiency may be small. The metal may include at least one selected from the group consisting of highly reflective metals, e.g., silver (Ag), aluminum (Al), gold (Au), copper (Cu), palladium (Pd), platinum (Pt), rhodium (Rh), and an alloy thereof. The first reflective surface <NUM> may be formed by deposition. The reflective paint may include reflective materials such as titanium oxide (TiO <NUM>), zinc oxide (ZnO), calcium carbonate (CaCo <NUM>), and the like having a reflectivity of <NUM>-<NUM>%, taken alone or in combination. The reflective paint may be diluted in a solvent together with an adhesive and coated on a material such as plastic. As a coating method, a spray, a roller, or the like may be used.

Based on the first reflector <NUM> having a symmetrical shape with reference to the central axis X, the first reflector <NUM> receives light incident in an omnidirection of a lateral direction. Herein, the lateral direction may indicate a direction perpendicular to the central axis X of the first reflector <NUM>, and the omnidirection of the lateral direction indicates <NUM> degrees of the direction perpendicular to the central axis X of the first reflector <NUM>. In addition, because the first reflector <NUM> includes the first reflective surface <NUM> having a tapered shape with a width gradually narrowing from an upper area to a lower area thereof, the first reflector <NUM> may reflect incident light downward such that the reflected light is converged.

Therefore, the LIDAR device <NUM> according to an embodiment does not have to rotate the light detector <NUM>, the first reflector <NUM>, or the like to detect the second light L2. Because a motor for rotating the first reflector <NUM> or the light detector <NUM> may not be included, a structure of the LIDAR device <NUM> may be more simplified.

The light source <NUM>, the first reflector <NUM>, and the light detector <NUM> may be sequentially arranged on the central axis X. For example, the light source <NUM> may be arranged at an upper side of the first reflector <NUM>, and the light detector <NUM> may be arranged at a lower side of the first reflector <NUM> opposite to the light source <NUM>.

The first reflector <NUM> includes a cavity <NUM> that is a vacant space inside an upper area thereof, and the light source <NUM> is arranged in the cavity <NUM>. Based on the light source <NUM> and the first reflector <NUM> being arranged in an overlapping manner, a size of the LIDAR device <NUM> may be reduced.

In addition, a second reflector <NUM> omnidirectionally emitting light may be further arranged at an upper side of the light source <NUM>. The second reflector <NUM> may include a reflective surface <NUM> having a tapered shape with a width gradually narrowing from an upper area to a lower area thereof. The reflective surface <NUM> of the second reflector <NUM> may include an area having a constant angle of inclination with respect to the central axis X and include an area having a variable angle of inclination with respect to the central axis X. Although <FIG> shows that the reflective surface <NUM> of the second reflector <NUM> has a reverse-cone shape, the reflective surface <NUM> is not limited thereto.

Based on the second reflector <NUM> including the reflective surface <NUM> having a tapered shape with a width gradually narrowing from an upper area to a lower area thereof, the second reflector <NUM> may reflect light incident from a lower side to the lateral direction. Based on the second reflector <NUM> having a symmetrical shape with reference to the central axis X, the second reflector <NUM> may omnidirectionally emit light. Although <FIG> shows that the first reflector <NUM> has the same shape as the second reflector <NUM>, the first reflector <NUM> and the second reflector <NUM> are not limited thereto. The first reflector <NUM> may have a shape different from that of the second reflector <NUM>, and the first reflector <NUM> and the second reflector <NUM> may have the same size or different sizes.

The processor <NUM> may determine location information of the object <NUM> by using a detection result of the light detector <NUM>. The location information of the object <NUM> may include at least one of a direction, a height, or a distance to the object <NUM> from the LIDAR device <NUM>. The processor <NUM> may determine at least one of the direction or the height where the object <NUM> exists by using a location of a pixel in the light detector <NUM> which has detected light, and determine the distance to the object <NUM> by using a light detection time of the pixel.

The processor <NUM> may determine the direction where the object <NUM> exists by using an azimuth of a pixel in the light detector <NUM>, the pixel having detected the second light L2. The processor <NUM> may determine the height of the object <NUM>, e.g., a height from the ground to the object <NUM>, by using a distance from the pixel which has detected the second light L2 to a reference point of the light detector <NUM>, e.g., a point where the central axis X meets the light detector <NUM>. For example, the processor <NUM> may determine that the greater the distance from the pixel which has detected the second light L2 to the reference point, the greater the height of the object <NUM>.

In addition, the processor <NUM> may detect a peak from an electrical signal applied from the light detector <NUM>. The processor <NUM> may detect the peak by detecting a central location of the electrical signal detecting a width of the electrical signal in an analog way. The processor <NUM> may detect the peak by converting the electrical signal into a digital signal, and then detecting a leading edge and a trailing edge of the digital signal or detect the peak by using a constant fraction discriminator (CFD) scheme. The processor <NUM> may further include a comparator to output the detected peak as a pulse signal.

The processor <NUM> may determine the distance of the object <NUM> by using the detected peak. For example, the processor <NUM> may measure the distance of the object <NUM> by using a detection time of the detected peak and an emission time of the light emitted from the light source <NUM>.

Based on the processor <NUM> determining the distance of the object <NUM> by using a light emission time of the light source <NUM> and a light detection time of the light detector <NUM>, unlike a triangulation method, a constant distance between the light source <NUM> and the light detector <NUM> does not have to be maintained. Therefore, the LIDAR device <NUM> may be miniaturized.

<FIG> shows that the first reflector <NUM> and the light detector <NUM> are sequentially arranged on the central axis X. The light source <NUM> and the second reflector <NUM> may be a light transmission end, and the first reflector <NUM> and the light detector <NUM> may be a light reception end. However, embodiments are not limited thereto. The first reflector <NUM> may not only reflect the second light L2 reflected from the object <NUM> to the light detector <NUM> but also omnidirectionally reflect and emit the first light L1 output from the light source <NUM>. That is, the first reflector <NUM> may be one component of the light transmission end and one component of the light reception end.

<FIG> illustrates a LIDAR device 100a including a light path changer <NUM> according to an embodiment. When compared with the LIDAR device <NUM> of <FIG>, the LIDAR device 100a of <FIG> may further include the light path changer <NUM> changing the path of the first light L1 emitted from the light source <NUM> to be incident to the first reflector <NUM> and changing the path of the second light L2 reflected from the object <NUM> to be incident to the light detector <NUM>. The light path changer <NUM> may include at least one of a beam splitter or a transflective film.

As shown in <FIG>, the light path changer <NUM> may be arranged between the first reflector <NUM> and the light source <NUM> along a central axis X. In addition, the light source <NUM> may be arranged in the lateral direction of the light path changer <NUM>. Accordingly, the light path changer <NUM> may transmit the first light L1 emitted from the light source <NUM> such that the first light L1 is incident to the first reflector <NUM> and reflect the second light L2 reflected from the object <NUM> such that the second light L2 is incident to the light detector <NUM>. As described above, the light source <NUM> and the light detector <NUM> may be arranged at a lower side of the first reflector <NUM>, thereby reducing a height of the LIDAR device 100a. In addition, without the second reflector <NUM>, the first reflector <NUM> may omnidirectionally emit the first light L1 and omnidirectionally receive the second light L2.

<FIG> illustrates a LIDAR device 100b according to an embodiment. When compared with <FIG>, the light source <NUM> shown in <FIG> may be arranged in the lateral direction of the light path changer <NUM>, and the light detector <NUM> may be arranged at a lower side of the light path changer <NUM>. Accordingly, the light path changer <NUM> may reflect the first light L1 emitted from the light source <NUM> such that the first light L1 is incident to the first reflector <NUM> and transmit the second light L2 reflected from the object <NUM> such that the second light L2 is incident to the light detector <NUM>.

<FIG> illustrates a LIDAR device 100c including a light path changer 160a having a hole h according to an embodiment. When compared with <FIG>, the light path changer 160a may include the hole h through which the first light L1 emitted from the light source <NUM> is transmitted to the first reflector <NUM>. The hole h may be arranged symmetrically with reference to the central axis X of the first reflector <NUM>. Based on the the first light L1 emitted from the light source <NUM> being incident to the first reflector <NUM> through the hole h, the light path changer 160a may be a reflective film in addition to being a beam splitter and a transflective film.

<FIG> illustrates a light transmission end <NUM> according to an embodiment. As shown in <FIG>, a collimating lens <NUM> may be arranged between the light source <NUM> and a reflector 130a. The reflector 130a shown in <FIG> may be the second reflector <NUM> shown in <FIG> or the first reflector <NUM> shown in <FIG>. The first light L1 emitted from the light source <NUM> may be output as parallel light after being transmitted through the collimating lens <NUM>. The parallel light may be incident to the reflector 130a and reflected to an omnidirection of the lateral direction. Based on the parallel light maintaining a parallel state thereof even after the parallel light is reflected from the reflector 130a, the parallel light may be more useful to recognize the object <NUM> located at a certain height from the ground.

To recognize the object <NUM> located at various heights, the LIDAR device <NUM> according to an embodiment may further include a diffuser. <FIG> illustrates a light transmission end 200a including a diffuser <NUM> according to an embodiment. As shown in <FIG>, the light transmission end 200a may further include the diffuser <NUM> between the light source <NUM> and the reflector 130a. Herein, the reflector 130a may be the first reflector <NUM> as illustrated in <FIG>, and <FIG> or the second reflector <NUM> as illustrated in <FIG>. The diffuser <NUM> may include a diffractive optical elements (DOE) lens capable of emitting light in a shape of several circles. The diffuser <NUM> may diffuse the first light L1 emitted from the light source <NUM> such that the diffused first light L1 is incident to the reflector 130a. The first light L1 reflected from the reflector 130a may be emitted on a space wider than that by the second reflector <NUM> shown in <FIG> or the first reflector <NUM> shown in <FIG>.

<FIG> illustrates a light transmission end 200b including a diffuser 174a according to an embodiment. The diffuser 174a shown in <FIG> may be arranged at an outer periphery of the reflector 130a, for example, between the reflector 130a and an object. Herein, the reflector 130a may be the first reflector <NUM> as illustrated in <FIG>, and <FIG> or the second reflector <NUM> as illustrated in <FIG>. Accordingly, the first light L1 emitted from the light source <NUM> may be reflected from the reflector 130a and then diffused by the diffuser 174a. The first light L1 diffused by the diffuser 174a may be emitted on an external space of various heights.

<FIG> illustrates a light transmission end 200c including a diffuser 174b according to an embodiment. As shown in <FIG>, a first reflector 130b may include a first reflective surface 131a arranged in an upper area thereof and a diffuser 174b arranged in a lower area thereof. Accordingly, the first light L1 emitted from the light source <NUM> may be incident to the diffuser 174b of the first reflector 130b, reflected and diffused from the diffuser 174b, and emitted on an external space. In addition, the second light L2 incident from the external space may be reflected from the first reflective surface 131a and incident to a light detector. The diffuser 174b may include a concave and convex pattern. <FIG> shows that the diffuser 174b is integrated in the first reflector 130b. However, the diffuser 174b is not limited thereto. The diffuser 174b may be integrated in the second reflector <NUM>.

<FIG> illustrates a light reception end <NUM> according to an embodiment. As shown in <FIG>, a condensing lens <NUM> may be further arranged between the reflector 130a and the light detector <NUM>. The reflector 130a may be the first reflector <NUM> shown in <FIG>. The condensing lens <NUM> may condense light reflected from the reflector 130a such that the condensed light is incident to the light detector <NUM>. Because the condensing lens <NUM> condenses light, a cross-sectional size of the light detector <NUM> may be smaller than a cross-sectional size of the reflector 130a. Accordingly, the LIDAR device <NUM> may be miniaturized.

It has been described that the LIDAR device <NUM> emits light in an omnidirection of the lateral direction of the first reflector <NUM>, i.e., the LIDAR device <NUM>. The LIDAR device <NUM> according to an embodiment may be applied to, for example, a robot cleaner. The robot cleaner may generate a map or recognize a current location on the map by the LIDAR device <NUM> to recognize an object arranged in the lateral direction.

The LIDAR device <NUM> may need to recognize an object <NUM> arranged at a lower side thereof that has a smaller height than the LIDAR device <NUM>. For example, the robot cleaner may control a motion of the robot cleaner by recognizing the object <NUM> arranged at a lower side thereof, e.g., an obstacle, while moving.

<FIG> illustrate LIDAR devices 100d and 100e according to embodiments. When compared with <FIG>, the LIDAR device 100d of <FIG> may further include an additional light source <NUM> emitting third light L3 in a lower direction of a first reflector 130c.

The first light L1 output from the light source <NUM> may be emitted in the lateral direction of the LIDAR device 100d, and the third light L3 output from the additional light source <NUM> may be emitted in the lower direction of the LIDAR device 100d. Accordingly, a first space in which the first light L1 output from the light source <NUM> is emitted may differ from a second space in which the third light L3 output from the additional light source <NUM> is emitted. For example, the first space may not overlap at least a partial area of the second space. The first space may be a space in the lateral direction of the LIDAR device 100d, and the second space may be a space in the lower direction of the LIDAR device 100d.

A second reflective surface <NUM> may be further arranged on an upper end of the first reflector 130c. The second reflective surface <NUM> may be arranged to protrude from the upper end of the first reflector 130c toward the lateral direction of the first reflector 130c. Accordingly, fourth light L4 reflected or scattered from the object <NUM> among the third light L3 emitted in the second space may be sequentially reflected from the second reflective surface <NUM> and the light path changer <NUM> and incident to the light detector <NUM>.

The first light L1 and the third light L3 may have the same wavelength or different wavelengths. When the first light L1 and the third light L3 have the same wavelength, the light source <NUM> and the additional light source <NUM> may alternately emit light, and the light detector <NUM> may also alternately detect the third light L3 and the fourth light L4 by being synchronized with the light source <NUM> and the additional light source <NUM>. In addition, the processor <NUM> may also determine location information of the object <NUM> by being synchronized with the light detector <NUM> and using a location and a detection time of a pixel which has detected the third light L3 or the fourth light L4. When the first light L1 and the third light L3 have different wavelengths, the light source <NUM> and the additional light source <NUM> may alternately or simultaneously emit light. The light detector <NUM> may include pixels discriminatively arranged to detect respective wavelengths of the first light L1 and the third light L3.

According to an embodiment, as shown in <FIG>, an additional light source 112a may emit the third light L3 having an emission angle different from that of the first light L1. The third light L3 may be emitted in both the lower direction and the lateral direction of the LIDAR device 100e. For example, the additional light source 112a may be illumination light having a relatively wide emission angle. Generally, the first light L1 may be used to recognize a portion of the object <NUM> located at a certain height, and the second light L2 may be used to recognize the object <NUM> located in a certain direction, e.g., at the front of the LIDAR device <NUM>, regardless of the height of the object <NUM>.

The first reflector <NUM> and the second reflector <NUM> described above have a reverse-cone shape. However, the first reflector <NUM> and the second reflector <NUM> are not limited thereto.

<FIG>, and <FIG> illustrate first reflectors 130d, 130e, 130f, and <NUM> of various shapes. As shown in <FIG>, the first reflector 130d has a reverse-cone shape but may have different angles of inclination θ according to areas thereof. For example, the first reflector 130d may include a first area <NUM> in which light is received to emit the light and a second area <NUM> in which light is received to detect the light. When the first light L1 emitted from the light source <NUM> is incident to the first reflector 130d along the central axis X, an angle of inclination θ of the first reflector 130d may be <NUM> degrees or less for uniform emission of light. Meanwhile, as the angle of inclination θ of the first reflector 130d is larger, pixels located at various locations of the light detector <NUM> may detect the second light L2 reflected or scattered from the object <NUM>. Therefore, the angle of inclination θ of the first area <NUM> may be <NUM> degrees or less, and the angle of inclination θ of the second area <NUM> may be greater than <NUM> degrees and less than <NUM> degrees. However, the angles of inclination θ of the first area <NUM> and the second area <NUM> are not limited thereto. The angle of inclination θ of the first area <NUM> and the second area <NUM> may be differently determined according to locations of the light source and the light detector and an application purpose of a LIDAR device 100f.

According to an embodiment, as shown in <FIG>, the angles of inclination θ of the first reflectors 130e and 130f, i.e., an angle between the central axis X and a tangent of a first reflective surface, may continuously vary according to heights of areas of the first reflectors 130e and 130f. The angle of inclination θ discontinuously varies at a boundary between the first area <NUM> and the second area <NUM> in <FIG>, whereas the angle of inclination θ may continuously vary from a lower area to an upper area thereof. <FIG> shows that the angle of inclination θ continuously decreases from a lower area to an upper area of the first reflector 130e to allow the second light L2 reflected or scattered from the object <NUM> to converge to the light detector <NUM>. However, the rate of change in the angle of inclination θ is not limited thereto. For example, as shown in <FIG>, the angle of inclination θ may continuously decrease at a slower rate from a lower area to an upper area thereof.

According to an embodiment, as shown in <FIG>, the angle of inclination θ of the first reflector <NUM> may be constant in a partial area of the first reflector <NUM> and continuously vary in the other partial area of the first reflector <NUM>. <FIG> shows that a lower area <NUM> of the first reflector <NUM> has a constant angle of inclination, and an upper area <NUM> of the first reflector <NUM> has the angle of inclination gradually decreasing upward. The lower area <NUM> is an area in which the first light L1 output from the light source <NUM> is emitted to an external space and may have the constant angle of inclination to emit light in a certain size of an external space. In addition, the upper area <NUM> may have the angle of inclination gradually decreasing upward to allow the second light L2 reflected or scattered from the object <NUM> to converge to the light detector <NUM>. The angle of inclination θ of a reflector may be differently formed according to devices to which the LIDAR device <NUM> according to an embodiment is applied or objects to be recognized.

As described above, because a reflector has a shape symmetrical with reference to the central axis X and tapered from an upper area to a lower area thereof, the reflector may omnidirectionally receive or emit light. Accordingly, a separate motor or the like is not necessary, and thus, a structure of a LIDAR device may be more simplified and miniaturized.

A LIDAR device 100j according to an embodiment may transmit light by using a fisheye lens. <FIG> illustrates the LIDAR device 100j including a fisheye lens <NUM> according to an embodiment. As shown in <FIG>, the LIDAR device 100j may include the light source <NUM> emitting the first light L1, the light detector <NUM> configured to detect the second light L2 that is a portion of the first light L1 reflected or scattered by the object <NUM> among the first light L1, the second reflector <NUM> emitting the first light L1 incident from the light source <NUM> to an omnidirection of the lateral direction, and the fisheye lens <NUM> refracting the second light L2 from an omnidirection such that the refracted second light L2 is incident to the light detector <NUM>.

The second reflector <NUM> may include the reflective surface <NUM> having a tapered shape with a width gradually narrowing from an upper area to a lower area thereof. The reflective surface <NUM> of the second reflector <NUM> may include an area having a constant angle of inclination with reference to a central axis X1 of the second reflector <NUM> and an area having a variable angle of inclination with reference to the central axis X1. Because the second reflector <NUM> includes the reflective surface <NUM> having a tapered shape with a width gradually narrowing from an upper area to a lower area thereof, the second reflector <NUM> may emit light incident from a lower side of the second reflector <NUM> to the lateral direction. Based on the second reflector <NUM> having a symmetrical shape with reference to the central axis X1, the second reflector <NUM> may omnidirectionally emit light.

The fisheye lens <NUM> may have a relatively wide angle of <NUM> degrees or more. Based on the wide angle of the fisheye lens <NUM> being <NUM> degrees or more, the fisheye lens <NUM> may refract the second light L2 incident within the wide angle such that the refracted second light L2 is incident to the light detector <NUM>. The fisheye lens <NUM> may not be arranged on a traveling path of the first light L1. The fisheye lens <NUM> may be arranged by being shifted away from the central axis X1. For example, a central axis X2 of the fisheye lens <NUM> may be identical to a central axis of the light detector <NUM>, and may not be identical to the central axis X1 of the second reflector <NUM>. The fisheye lens <NUM> may be arranged at a lower location than a location at which the second reflector <NUM> is arranged. Accordingly, the fisheye lens <NUM> may not receive the first light L1 emitted from the light source <NUM> or the first light L1 reflected from the second reflector <NUM>.

When the incident second light L2 is refracted to the light detector <NUM> by using the fisheye lens <NUM>, optical efficiency may be higher than when incident light is reflected to the light detector <NUM> by using a reflector.

According to an embodiment, the LIDAR device 100j may further include a processor configured to determine location information of the object <NUM> by using a detection result of the light detector <NUM>. The location information of the object <NUM> may include at least one of a direction, a height, or a distance of the object <NUM> from the LIDAR device 100j. The processor may determine at least one of the direction or the height where the object <NUM> exists by using a location of a pixel in the light detector <NUM>, which has detected light, and determine the distance to the object <NUM> from the LIDAR device 100j by using a light detection time of the pixel.

The processor may determine the direction where the object <NUM> exists by using an azimuth of a pixel in the light detector <NUM>, the pixel having detected the second light L2. The processor may determine the height of the object <NUM>, e.g., a height from the ground to the object <NUM>, by using a distance from the pixel which has detected the second light L2 to the reference point of the light detector <NUM>, e.g., a point where the central axis X2 meets the light detector <NUM>. For example, the processor may determine that the greater the distance from the pixel which has detected the second light L2 to the reference point, the greater the height of the object <NUM>.

In addition, the processor may detect a peak from an electrical signal applied from the light detector <NUM> and determine the distance to the object <NUM> by using the detected peak. For example, the processor may measure the distance to the object <NUM> by using a detection time of the detected peak and an emission time of light emitted from the light source <NUM>.

<FIG> illustrates a LIDAR device <NUM> including the fisheye lens <NUM>, according to an embodiment. When compared with <FIG>, the LIDAR device <NUM> of <FIG> may further include the additional light source <NUM> emitting the third light L3 in a lower direction of the LIDAR device <NUM>. The first light L1 output from the light source <NUM> may be emitted in the lateral direction of the LIDAR device <NUM>, and the third light L3 output from the additional light source <NUM> may be emitted in the lower direction of the LIDAR device <NUM>. Accordingly, a first space in which the first light L1 output from the light source <NUM> is emitted may differ from a second space in which the third light L3 output from the additional light source <NUM> is emitted. For example, the first space may not overlap at least a partial area of the second space. The first space may be a space in the lateral direction of the LIDAR device <NUM>, and the second space may be a space in the lower direction of the LIDAR device <NUM>.

In addition, the second reflective surface <NUM> may be further arranged at an upper side of the fisheye lens <NUM>. The second reflective surface <NUM> may be arranged to protrude from an upper end of the second reflector <NUM> toward the lateral direction of the second reflector <NUM>. Accordingly, the fourth light L4 reflected or scattered from the object <NUM> among the third light L3 emitted in the second space may be reflected from the second reflective surface <NUM> and then incident to the light detector <NUM> through the fisheye lens <NUM>. In addition, the second light L2 reflected or scattered from the object <NUM> among the first light L1 emitted in the first space may be incident to the light detector <NUM> through the fisheye lens <NUM>.

The first light L1 and the third light L3 may have the same wavelength or different wavelengths. When the first light L1 and the third light L3 have the same wavelength, the light source <NUM> and the additional light source <NUM> may alternately emit light, and the light detector <NUM> may also alternately detect the third light L3 and the fourth light L4 by being synchronized with the light source <NUM> and the additional light source <NUM>. In addition, the processor may also determine location information of the object <NUM> by being synchronized with the light detector <NUM> and using a location and a detection time of a pixel which has detected the third light L3 or the fourth light L4. When the first light L1 and the third light L3 have different wavelengths, the light source <NUM> and the additional light source <NUM> may alternately or simultaneously emit light. The light detector <NUM> may include pixels discriminatively arranged to detect respective wavelengths of the first light L1 and the third light L3.

<FIG> illustrates a LIDAR device <NUM> according to an embodiment. When compared with <FIG>, the second reflector <NUM> and the second reflective surface <NUM> may be connected by using a transparent member <NUM>. Accordingly, the fisheye lens <NUM> may also refract light L5 incident from an upper part of the LIDAR device <NUM> such that the refracted light L5 is incident to the light detector <NUM>. The light L5 incident from the upper part may have a wavelength different those of the second light L2 and the fourth light L4.

As described above, according to embodiments, when a reflector and a fisheye lens are used, light may be omnidirectionally emitted or received even without a motor.

Further, according to embodiments, a structure of a LIDAR device may be more simplified by using a reflector omnidirectionally emitting or receiving light. In addition, omnidirectional light may be received by using a reflector or a fisheye lens without a motor.

Further still, according to embodiments, a structure of a LIDAR device may be more simplified by a reflector omnidirectionally emitting or receiving light.

Claim 1:
A light detection and ranging, LIDAR, device (<NUM>) comprising:
a first light source (<NUM>) configured to emit first light;
a first reflector (<NUM>) comprising a reflective surface (<NUM>) symmetrical with reference to a central axis of the first reflector (<NUM>) and configured to receive second light that is light reflected or scattered by an object that is irradiated by the first light in <NUM> degrees of a lateral direction to the central axis of the first reflector (<NUM>), and reflect the second light;
a light detector (<NUM>) comprising a pixel array, the light detector (<NUM>) being configured to detect the second light reflected from the first reflector (<NUM>); and
a processor (<NUM>) configured to acquire location information of the object based on detection of the second light by the light detector (<NUM>),
wherein the first reflector (<NUM>) has a tapered shape with a width gradually narrowing from an upper area of the first reflector (<NUM>) to a lower area of the first reflector (<NUM>);
characterized in that
the first reflector (<NUM>) comprises a cavity (<NUM>) that is a vacant space provided inside an upper area of the first reflector (<NUM>), and
the first light source (<NUM>) is provided in the cavity (<NUM>).