KR20210116369A - 2-Dimensional scanning optical system by simple objective lens sequential actuation - Google Patents

Abstract

The present invention relates to a two-dimensional scanning optical system using simple sequential control of objective lens positions, which can overcome the technical limitations of solid-state LiDAR sensors, such as field of view (FOV) and measuring distance, thereby enabling ultra-wide-angle spatial detection. In accordance with an embodiment of the present invention, a two-dimensional scanning optical system using simple sequential control of objective lens positions comprises: a light source unit; a first condensing lens; an optical steering unit; a driving unit; a magnification adjustment optical unit; and a wide-angle lens unit. The light source unit emits laser light. The first condensing lens is provided in a path of the laser light emitted from the light source unit to convert the laser light so that the same is parallel to an optical axis, or to reduce the angle at which the laser light is emitted. The optical steering unit is installed on a path of the light converted through the first condensing lens to adjust the position at which the laser light is formed. The driving unit drives the optical steering unit. The magnification adjustment optical unit enlarges or reduces the laser light of which the optical path has been changed through the optical steering unit so as to be positioned on a preset image plane of the wide-angle lens unit, to form an image. The wide-angle lens unit emits the laser light having passed through the image plane at a preset angle and area to increase the scan area and FOV of the laser light.

Description

Two-dimensional scanning optical system by simple objective lens sequential actuation

The present invention relates to a two-dimensional scanning optical system through a simple objective lens position sequential control, and more particularly, overcomes technical limitations of solid-state lidar sensors such as FOV (Field of View) and measurement distance Thus, it relates to a two-dimensional scanning optical system through a simple objective lens position sequential control that enables ultra-wide-angle spatial detection.

In general, a light detection and ranging (LiDAR) sensor is a survey technology that measures the distance to a target through a laser light source. shape can be measured. The LiDAR sensor has been used as a means to supplement the camera function by being installed in spacecraft and rover, and recently, its importance is increasing as it is used as a core technology for the 3D image camera of the future driverless vehicle.

Currently, the LiDAR sensor developed for 3D image modeling of unmanned vehicles is a 3D laser scanner type that collects image information by rotatingly scanning the light irradiated from the laser, and a 3D laser scanner type that collects image information by expanding the laser beam and then reflecting it. It is classified as a 3D Flash type that acquires real-time image information by receiving light through a multi-array receiving element. The 3D laser scanner type has problems in size and stability due to the scanning module, and the 3D Flash type has problems in developing a receiver to secure resolution and viewing angle.

Meanwhile, in order to apply the LiDAR sensor to the autonomous driving environment of actual commercial vehicles, it is very important to lower the system cost of the LiDAR sensor so that it can be applied to mass production. To this end, research on decomposing the space by disposing a plurality of small lidar sensors with small scan angles in all directions of the vehicle is being actively conducted.

Solid-state LiDAR sensor has a great advantage in miniaturization due to the fact that it has no or minimized mechanical driving part, so it is being actively developed by top tier electronic component companies around the world including OSLAM. However, the operating characteristics of the photovoltaic element that deflects the light flux and the Focal Plane Array that detects the light flux scattered from the object are sensitive to the driving environment such as temperature, humidity, vibration, and shock, and the measurement It has not yet been actively applied to actual autonomous driving tests because the response area (FOV) is as narrow as 40° or less, and a light source with extremely high output is required for distance measurement of 50m or more.

Several automakers that are implementing level 4 or higher autonomous driving technology that drive without driver intervention are achieving excellent autonomous driving performance by applying a LiDAR sensor with a miniaturized rotating mechanism. However, in this case, it is difficult to further miniaturize the sensor because a plurality of high-output light sources and a high-inertia rotating mechanism are required, and it is difficult to apply the sensor to various vehicle types considering that a plurality of sensors must be applied due to the high sensor cost.

Republic of Korea Patent No. 10-1773020 (Announced on September 12, 2017)

Therefore, the technical problem to be achieved by the present invention is to solve the conventional disadvantages, and it is possible to recognize and compensate in real time the detection position error according to the change of the sensor driving conditions such as temperature, vibration, and shock according to the change of the driving environment of the vehicle. It aims to provide a lidar sensor that has a driving mechanism and can detect an ultra-wide angle (>150°) space by overcoming the technical limitations of solid-state lidar sensors such as FOV and measuring distance.

A two-dimensional scanning optical system through a simple objective lens position sequential control according to an aspect of the present invention for achieving this technical task is a light source unit, a first condensing lens, an optical steering unit, a driving unit, a magnification adjustment optical unit, a wide-angle lens unit, and a luminous flux. It may include a division element, a third condensing lens, a detector, and a controller.

The light source unit irradiates laser light. The first condensing lens is provided on a path of the light irradiated from the light source unit to convert the laser light to be parallel to the optical axis or reduce an angle at which the laser light is emitted. In addition, the optical steering unit is installed on the optical path converted through the first condensing lens to adjust a position at which the laser light is imaged on the intermediate virtual imaging plane.

The driving unit drives the optical steering unit. The magnification adjustment optical unit enlarges or reduces the laser light whose optical path is changed through the optical steering unit so as to be positioned on the image plane of the preset wide-angle lens unit to form an image. In addition, the wide-angle lens unit radiates the laser light passing through the image plane at a preset angle and area in order to increase the scanning area and FOV (Field of View) of the laser light.

The beam splitter guides the laser beam reflected from the measurement object to the detector. The third condensing lens is provided between the beam splitter and the detector to condense the light beam reflected from the beam splitter and transmit it to the detector. The detector detects the measurement target by receiving the reflected light and converting it into electricity.

The controller controls the light source unit, the first condensing lens, the magnification adjustment optical unit, the wide-angle lens unit, the beam splitter, the third condensing lens and the detector, and sets the emission range of the laser light, and the angle of the laser light according to the emission range to control the driving unit so that the laser light irradiated from the light source unit can pass through the image plane of the wide-angle lens unit.

In addition, the two-dimensional scanning optical system through a simple objective lens position sequential control according to another aspect of the present invention may include a light source unit, a first condensing lens, a MEMS mirror, a driving unit, a scanning lens unit, and a wide-angle lens unit. .

The light source unit irradiates laser light. The first condensing lens is provided on the path of the light irradiated from the light source unit to convert the laser light to be parallel to the optical axis or to reduce the angle at which the laser light is emitted. In addition, the MEMS mirror is installed on the optical path that has passed through the first condensing lens to two-dimensionally change and scan the light beam incident from the first condensing lens.

The scanning lens unit forms a focal point on the focal plane of the wide-angle lens unit according to the scanning angle by the MEMS mirror, and then the light flux scanned through the MEMS Mirror is transmitted into the incident surface of the wide-angle lens unit. is imaged on the focal plane of the wide-angle lens unit. In addition, the wide-angle lens unit radiates the laser light passing through the incident surface at a preset angle and area in order to increase a scan area and a field of view (FOV) of the laser light.

As described above, the two-dimensional scanning optical system through the sequential control of the position of the objective lens according to the present invention sequentially scans the light beam in the horizontal and vertical directions through a simple driving principle to determine the detection distance and FOV (Field of View). By improving it, it is possible to realize a small-sized LiDAR sensor with low net cost, and it has an easy-to-control driving mechanism to secure driving stability for the vehicle driving environment, thereby stably driving autonomous vehicles. It has the effect of acquiring high-resolution and real-time image information for

1 is a conceptual diagram illustrating a scanning optical system according to an embodiment of the present invention.
2 is a block diagram illustrating a scanning optical system according to an embodiment of the present invention.
3 is a block diagram illustrating a scanning optical system according to an embodiment of the present invention.
4A and 4B are diagrams illustrating adjusting the angle of light using a liquid lens in the present invention.
5 is a view showing a multi-electrode liquid lens according to another embodiment of the present invention.
6 is a block diagram showing a scanning optical system according to another embodiment of the present invention.
7 is a diagram illustrating an intermediate virtual image plane (IIP) according to an embodiment of the present invention.
8 is a block diagram illustrating a scanning optical system according to another embodiment of the present invention.
9 is a block diagram showing a scanning optical system according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated. In addition, terms such as “…unit”, “…group”, “…module”, etc. described in the specification mean a unit that processes at least one function or operation, which is implemented by hardware or software or a combination of hardware and software. can be

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings.

Like reference numerals in each figure indicate like elements.

1 is a conceptual diagram illustrating a two-dimensional scanning optical system through a simple objective lens position sequential control according to an embodiment of the present invention, and FIG. 2 is a two-dimensional scanning optical system through a simple objective lens position sequential control according to an embodiment of the present invention. It is a block diagram representing the system.

The two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention includes a light source unit 100, a first condensing lens 200, an optical steering unit 300, a driving unit 400, It may include a magnification adjustment optical unit 500 and a wide-angle lens unit 600 .

The light source unit 100 may irradiate laser light. Preferably, the light source unit 100 may include a laser diode irradiating a single laser light. The first condensing lens 200 may be provided on a path of the light irradiated from the light source unit 100 to convert the laser light into parallel light so that the laser light is parallel, or reduce the radiation angle at which the laser light is emitted. Here, the first condensing lens 200 may be a collimator lens.

In order to move the image on the intermediate virtual imaging plane (IIP) 700 by changing the angle of the laser light passing through the first condensing lens 200 according to an embodiment of the present invention, the following two methods may be used.

One is to two-dimensionally adjust the imaging position in the intermediate virtual imaging plane (IIP) 700 by the objective lens by adjusting the position of the objective lens through the driving unit 400 in two dimensions. You can adjust the angle of radiation in the horizontal and vertical directions through the wide-angle lens.

The other is, by controlling the driving unit 400 to change the radius of curvature of the lens surface of the liquid lens, the image position on the intermediate virtual imaging plane (IIP) 700 may be moved.

In general, a liquid lens is used to compensate for de-focus of light, but the incident of deflected light on the liquid lens causes deflection of the emitted light, and on the intermediate virtual imaging plane (IIP) 700 . Images can be moved. In addition, by adjusting the radius of curvature of the liquid lens, it is possible to control the deflection angle and focal length of the incident light.

In addition, in order to overcome the disadvantages of a LiDAR sensor, which is generally easy to scan in a horizontal direction but difficult to scan in a vertical direction, the scanning optical system 10 according to an embodiment of the present invention includes an optical steering unit 300 ) and the driving unit 400 may be configured, and the driving unit 400 may be controlled to adjust the wide angles in the horizontal and vertical directions, respectively.

The optical steering unit 300 may be installed on a path of the laser light passing through the first condensing lens 200 to adjust a position at which the laser light is imaged on the intermediate virtual imaging surface 700 . The optical steering unit 300 may include a liquid lens module 310 and a second condensing lens 320 .

The liquid lens module 310 includes at least one liquid lens, and the second condensing lens 320 includes an objective lens or a general lens. The liquid lens may obtain fine spatial resolution by using a continuous voltage. In addition, the second condensing lens 320 may control the position of the objective lens or the general lens to adjust the deflection angle of the incident light.

3 is a block diagram illustrating a scanning optical system according to an embodiment of the present invention, and FIGS. 4A and 4B are diagrams illustrating the adjustment of the angle of light using a liquid lens in the scanning optical system according to an embodiment of the present invention. am. That is, FIG. 3 is a diagram illustrating changing the angle of the laser light passing through the first condensing lens 200 using the liquid lens module 310 . Of the four liquid lenses of FIG. 3 , two liquid lenses on the right may adjust the angle of the x-axis, and the two liquid lenses on the left may adjust the angle of the y-axis.

In addition, FIG. 4A is a view showing that the liquid lenses 311 and 313 through which the light passes through the vertex of the lens in FIG. 3 and the liquid lenses 312 and 314 eccentric from the central axis of the light form a pair to change the angle of the light. , FIG. 4B is a view showing changing the focal length by adjusting the radius of curvature of the liquid lens 312 eccentric in FIG. 4A.

In the case of changing the angle of light using a liquid lens, one-dimensional scanning is realized by adjusting the radius of curvature of each of a pair (two) of liquid lenses, and one pair for two-dimensional scanning driving (2) more liquid lenses are needed.

The liquid lens module 310 according to an embodiment of the present invention may include four liquid lenses. Each of the four liquid lenses forms two pairs, and adjusts the vertical (y-axis) direction angle of light using any one pair of liquid lenses 311 and 312 among the two pairs of liquid lenses, and the other pair of liquid lenses A horizontal (x-axis) direction angle of light may be adjusted by using the liquid lenses 313 and 314 .

That is, the angle of light can be changed to a desired angle by adjusting the radius of curvature of each liquid lens. As shown in FIG. 4A, in each pair of liquid lenses composed of two liquid lenses, any one of the liquid lenses 312 and 314 is configured such that the central axis is eccentric from the optical axis by a predetermined distance. By changing the radius of curvature, the scanning angle of the light can be changed.

At this time, the focal position may be changed due to a change in refractive power of the liquid lenses 312 and 314 eccentric from the central axis. That is, in FIG. 4b, the liquid lens 312 at the upper end is focused on the intermediate virtual imaging surface 700, but the liquid lens 312 at the lower end of which the radius of curvature is changed has an increased focal length. A focal point is not formed on the intermediate virtual imaging plane 700 .

In order to compensate for this, another liquid lens 311, 313 through which the incident light flux passes through the apex of the lens is constituted, and the focusing radius of the apex liquid lens 311 and 313 is adjusted to adjust the focusing of the light. Through this, the liquid lens module 310 can adjust the angle of the laser light to a desired position on a two-dimensional plane.

5 is a view showing a liquid lens having multiple electrodes according to another embodiment of the present invention. As shown in FIG. 5, the liquid lens module 310 according to an embodiment of the present invention adjusts the direction and voltage of the current induced from the input electrode of the liquid lens by using multiple electrodes. The emission angle and focal length of the incident laser light can be adjusted.

That is, the optical steering unit 300 may be formed of two liquid lenses having multiple electrodes. In this case, the driving unit 400 includes a voltage supply module 410 capable of independently applying voltages to multiple electrodes.

In addition, by adjusting the input voltage applied independently from the voltage supply module 410 to each of the multiple electrodes of the liquid lens having the multiple electrodes, the curvature of the interface of the heterogeneous liquids having different refractive indices and By changing the position of the interface vertex point, it is possible to control the emission angle and focal length of the laser light emitted from the optical steering unit 300 .

For example, in the left drawing of FIG. 5 , when the upper first voltage 310c is applied relatively higher than the lower second voltage 310d, Oil 310a and Water 310b) Since the curved surface 310e made of the interface of is thicker than the upper layer, the incident laser light is emitted relatively downward. Conversely, in the right diagram of FIG. 5 , when the second voltage 310d at the lower end is applied relatively higher than the first voltage 310c at the upper end, it is composed of Oil 310a and Water 310b. Since the curved surface 310e is formed thicker on the upper layer than the lower layer, the incident laser light is emitted relatively upward.

The liquid lens having multiple electrodes of FIG. 5 can implement beam steering in one axial direction with one element (liquid lens) by simultaneously changing the interfacial curvature and apex between the liquids. Therefore, in the case of FIG. 3, the laser light emission angle and focal length are controlled using four liquid lenses, whereas the liquid lens having multiple electrodes of FIG. 5 has two elements (liquid lenses). ) can be used to implement horizontal and vertical steering, and to control the emission angle and focal length of laser light.

As described above, by using a liquid lens having multiple electrodes, the number of liquid lenses for controlling the emission angle and focal length of laser light can be reduced.

Meanwhile, a wave plate may be further included between the first condensing lens 200 and the optical steering unit 300 . In addition, a prism may be further included between the optical steering unit 300 and the magnification adjustment optical unit 500 . Through this, the light irradiated from the light source unit 100 may be filtered to extract linearly polarized light.

The driving unit 400 may drive the optical steering unit 300 to selectively image the laser light on the two-dimensional intermediate virtual imaging plane (IIP) 700 . That is, the driving unit 400 includes a voltage supply module 410 for selectively supplying a voltage to each liquid lens in order to drive the liquid lens module 310 .

The voltage supply module 410 is operated under the control of the controller 1100 to selectively supply a voltage to the liquid lens module 310 . That is, when the liquid lens module 310 is composed of four liquid lenses having a single electrode, the controller 1100 controls the voltage supply module 410 to supply a voltage to a single electrode of each liquid lens.

In addition, when the liquid lens module 310 is composed of two liquid lenses having multiple electrodes, the controller 1100 controls the voltage supply module 410 to each of the multiple electrodes of each liquid lens. Voltage can be applied independently.

The driving unit 400 may drive at least one of the liquid lenses to adjust a vertical angle or a horizontal angle of light imaged on the intermediate virtual imaging plane 700 .

Also, the driving unit 400 may include an actuator 420 . Preferably, a micro-actuator 421 (not shown) may be used for precise control of the optical steering unit 300 . Also, the driving unit 400 may include at least one of an adaptive optics (AO) actuator, an electroosmotic (EO) actuator, a voice coil motor (VCM) actuator, and a linear actuator.

6 is a block diagram showing a two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to another embodiment of the present invention. That is, FIG. 6 is a view showing that the light flux is adjusted to be located on the intermediate virtual imaging plane (IIP) 700 by using the magnification optical unit 500 as an embodiment for further specifying the configuration of FIG. 1 .

As shown in FIG. 6 , the focal position of the laser light of the laser light passing through the first condensing lens 200 may be sequentially changed using the second condensing lens 320 .

In addition, as shown in FIG. 6 , the driving unit 400 adjusts the position of the second condensing lens 320 in two dimensions, up, down, left, and right to change the position of the focus by the second condensing lens 320 in two dimensions. can That is, by using the driving unit 400 to drive the second condensing lens 320 into which a parallel light beam is incident in a two-dimensional direction perpendicular to the optical axis, the position of the focus by the second condensing lens 320 is two-dimensionally up, down, left and right. can be changed negatively.

The driving unit 400 for driving the second condensing lens 320 may include at least one of a voice coil motor (VCM) actuator and a piezoelectric (PZT) actuator. In addition, the second condensing lens 320 may be an objective lens or a general lens.

In general, the size of the incident surface (sensor surface) of the wide-angle lens unit 600 is not the same as the size of the image area of the light whose angle is changed through the light steering unit 300 . If the wide-angle lens unit 600 is designed so that the size of the incident surface (sensor surface) of the wide-angle lens unit 600 is the same as the size of the image area of the light, the magnification adjustment optical unit 500 may not be used, so that the scanning The size of the optical system 10 can be innovatively reduced.

However, in this case, there is a disadvantage that the conventionally developed wide-angle lens cannot be used. Accordingly, the magnification adjustment optical unit 500 may change the size of the image area of the laser light whose optical path is changed through the optical steering unit 300 to correspond to the size of the incident surface (sensor surface) of the wide-angle lens unit 600 .

The magnification adjustment optical unit 500 may form an image by enlarging or reducing the laser light whose optical path has been changed through the optical steering unit 300 to be located on the image plane or the incident plane of the preset wide-angle lens unit 600 . In addition, the magnification adjustment optical unit 500 converts the radiation angle of the laser light so that the laser light whose optical path is changed through the optical steering unit 300 is incident parallel to the image plane of the preset wide-angle lens unit 600 can be transmitted. have.

That is, the magnification adjustment optical unit 500 enlarges or reduces the size of a region in which the light whose optical path is changed through the optical steering unit 300 can be located, so that the size of the sensor is determined in advance by the incidence of the wide-angle lens unit 600 . Light can be imaged in the surface (sensor surface) area. Alternatively, the light incident to the incident surface of the wide-angle lens unit 600 may be adjusted to be incident horizontally. In this case, the magnification adjustment optical unit 500 may be configured as a relay optical system composed of a plurality of lenses.

Here, the conversion of the light beam to be incident parallel to the image plane of the wide-angle lens unit 600 minimizes the loss of the light beam when the laser beam is spatially scanned through the wide-angle lens unit 600, and thus the amount of light for each angle scanned. There is an effect of suppressing variation and increasing the amount of detected light.

The two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention may be applied to a light detection and ranging (LiDAR) for an autonomous vehicle. The LiDAR sensor operates by irradiating near-infrared wavelength light through space and measuring the time of flight (TOF) of the light scattered from the measurement object.

In general, the factors that affect the performance of LiDAR are the power and wavelength of the light source, the sensitivity and dynamic range of the sensor, and the optical FOV and spatial resolution of the system. Among these factors, in terms of the FOV of the lidar sensor, if the light source is assigned to the image plane of the conventional broadband field optics, it can scan 3D space with a wide FOV. However, it is difficult to apply multiple lasers to the image plane.

The two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention transmits the laser light through the optical steering unit 300 to a two-dimensional intermediate image plane (IIP) (700). ), an array light source effect such as a two-dimensional light source on the intermediate virtual imaging plane 700 can be implemented.

7 is a diagram illustrating an intermediate virtual image plane (IIP) according to an embodiment of the present invention. The two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention is a virtual two-dimensional intermediate image plane (IIP, Intermediate Image Plane) on the incident surface of the wide-angle lens unit 600 ( 700) by setting a region, and allowing the light emitted from the light source unit 100 to be selectively imaged on the two-dimensional intermediate virtual image plane (IIP, Intermediate Image Plane) 700 region through the optical steering unit 300 . The same effect as having a two-dimensional light source in the two-dimensional intermediate virtual image plane (IIP) 700 may be exhibited.

The laser light passing through the intermediate virtual imaging plane (IIP) 700 or the image plane of the wide-angle lens unit 600 is incident on the wide-angle lens unit 600 and is emitted at a preset angle and area. The wide-angle lens unit 600 may include a fish-eye lens 610 . The wide-angle lens unit 600 is for securing a wide scan area of laser light and a Field of View (FOV), and may provide an angle of view of 180 degrees or more.

The two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention may further include a beam splitter 800 , a third condensing lens 900 , and a detector 1000 .

The beam splitter 800 may guide the laser light reflected from the measurement object to the detector 1000 . The third condensing lens 900 may be provided between the beam splitting device 800 and the detector 1000 to condense the light beam reflected from the beam splitting device 800 and transmit it to the detector 1000 .

The detector 1000 may detect the measurement target by receiving the reflected light and converting it into electricity. That is, the detector 1000 may detect the measurement object by acquiring reflected light formed by reflecting laser light on the measurement object. The detector 1000 may analyze the characteristics of the detection signal by using a Single Photon Avalanche Detector (SPAD).

The controller 1100 may control the driving unit 400 by setting an emission range of the laser light and determining an angle of the laser light according to the emission range. That is, the controller 1100 may control the driving unit 400 to adjust the optical steering unit 300 to adjust the angle of the laser light incident on the incident surface or the image surface of the wide-angle lens unit 600 .

Also, the controller 1100 may control the driving unit 400 so that the laser light irradiated from the light source unit 100 may pass through the image plane of the wide-angle lens unit 600 . In addition, the controller 1100 sets a virtual two-dimensional intermediate virtual image plane (IIP, Intermediate Image Plane) region, and a two-dimensional intermediate virtual image plane (IIP, Intermediate Image Plane) in which the laser light irradiated from the light source unit 100 is set. ), the driving unit 400 may be controlled to be projected onto the area.

Also, the controller 1100 may control the light source unit 100 , the first condensing lens 200 , the magnification adjustment optical unit 500 , and the detector 1000 .

Table 1. Compact LiDAR Sensor capable of ultra-precise wide-angle spatial resolution

Table 1 shows a compact LiDAR sensor capable of ultra-precise wide-angle spatial resolution by applying the scanning optical system 10 according to an embodiment of the present invention. As shown in Table 1, using the two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention, a horizontal angle of view (HFOV) of 150°, a vertical angle of view (VFOV) of 8° or more Positioning of objects in space is possible.

In addition, by using a single high-power laser to sequentially acquire information for each location in each space, it is possible to implement a measurement distance of 100m or more at the same level as that of a conventional mechanical rotating LiDAR (LiDAR). In addition, when the optical steering unit 300 is driven by 50 mm left and right using the driving unit 400, an FOV of 150° or more can be realized.

Since the conventional mechanical rotating lidar uses constant speed driving of a rotating body having a single reflective surface, it decomposes the vertical space by multiple laser beams incident at an angle to each other. It is not possible to compensate for errors occurring in the corresponding scan angles in the horizontal and vertical directions.

However, the two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention is compact and a low-cost actuator having excellent response characteristics is applied to the driving unit 400 to light The steering unit 300 may be driven in two dimensions. In addition, by sequentially scanning the beam emitted from a single laser in space, the horizontal and vertical angle information of the scanned beam can be directly known, and the detection element with a single segment can be used to measure each scanning angle. Since TOF (Time of Flight) can be detected, there is an effect that the system can be implemented more compactly.

8 is a block diagram showing a scanning optical system 10 according to another embodiment of the present invention, and FIG. 9 is a block diagram showing a scanning optical system 10 according to another embodiment of the present invention. That is, FIGS. 8 and 9 are views illustrating changing the angle of the laser light passing through the first condensing lens 200 using the MEMS Mirror 1200 .

The scanning optical system 10 according to an embodiment of the present invention scans (scans) parallel incident light beams in various directions using a MEMS Mirror 1200, and then sets the optical field to the flat. Wide-angle scanning can be implemented by directly forming an image on the intermediate virtual imaging surface 700 using the scanning lens unit 1300 that makes it flat.

As shown in FIGS. 8 and 9 , the scanning optical system 10 according to an embodiment of the present invention includes a light source unit 100 , a first condensing lens 200 , a MEMS Mirror 1200 , and a driving unit 400 . ), a scanning lens unit 1300 and a wide-angle lens unit 600 may be included.

The light source unit 100 may irradiate laser light. The first condensing lens 200 is provided on the path of the light irradiated from the light source unit 100 to convert the laser light into parallel light so that it is parallel to the optical axis or reduce the radiation angle at which the laser light is emitted.

The MEMS mirror 1200 is installed on the path of the light passing through the first condensing lens 200 , and two-dimensionally changes and scans the light flux incident from the first condensing lens 200 . The driving unit 400 may control the angle of light by driving the MEMS Mirror 1200 .

The scanning lens unit 1300 is an intermediate virtual image of the wide-angle lens unit 600 according to the scanning angle by the MEMS Mirror 1200 by changing the angle of the scanning lens unit 1300 through the MEMS Mirror 1200 . After forming a focus on the imaging plane (IIP) 700 or the focal plane, the light beam is transmitted into the image plane or the incident plane of the wide-angle lens unit 600. The intermediate virtual imaging plane (IIP) of the wide-angle lens unit 600 ( 700) or imaging on the focal plane.

In addition, the wide-angle lens unit 600 may radiate the laser light passing through the image plane or the incident surface at a preset angle and region in order to increase the scan area and Field of View (FOV) of the laser light.

The second condensing lens 320 using a VCM (Voice Coil Motor) actuator or the liquid lens module 310 using a liquid lens cannot realize a large driving frequency when the driving amount increases, so the image through the optical steering unit 300 There is little change in position. Therefore, the liquid lens module 310 or the second condensing lens 320 requires the magnification adjustment optical unit 500 to form an image on the incident surface of the wide-angle lens unit 600, but the MEMS Mirror (MEMS Mirror) ( 1200) does not require the magnification adjustment optical unit 500 because the driving frequency is high.

Accordingly, the scanning optical system 10 using the MEMS Mirror 1200 has an advantage in that it can form an image directly on the incident surface of the wide-angle lens unit 600 using the scanning lens unit 1300 .

As described above, the two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention is a conventional mechanism rotating type lidar that uses multiple laser light sources and multiple light receiving elements to decompose the space in the vertical direction. It can significantly reduce expensive component parts and overcome the technical weaknesses of the solid-state LiDAR sensor, which are being actively researched recently, that require the use of a narrow FOV, short detection distance, and expensive two-dimensional FPA. have.

In addition, through position control for the two-dimensional displacement of the optical steering unit 300, the positioning error of the sensor according to changes in the driving environment (temperature, humidity, vibration, shock, etc.) is minimized to secure driving stability compared to the conventional lidar sensor There is an effect that can be done. In addition, the two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention provides an optical/image processing solution that can solve distortion that may occur during wide-angle imaging and an imbalance in the amount of light for each angle of view. There is an effect of securing ultra-wide-angle spatial resolution characteristics, and there is an effect of securing robust operating characteristics in a driving environment through the ultra-precise control technology of the optical steering unit 300 according to temperature and humidity changes.

In addition, the two-dimensional scanning optical system 10 through a simple objective lens position sequential control according to an embodiment of the present invention is a liquid lens module 310 composed of a beam-biased liquid lens capable of realizing fine spatial resolution through continuous voltage control. ) and using the fisheye lens 610, there is an effect of improving the FOV.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and it is easily changed by a person skilled in the art from the embodiment of the present invention to equivalent It includes all changes to the extent recognized as such.

10: scanning optical system 100: light source unit
200: first condensing lens 300: optical steering unit
310: liquid lens module 310a: oil
310b: Water 310c: First voltage
310d: second voltage 310e: curved surface
311: first liquid lens 312: second liquid lens
313: third liquid lens 314: fourth liquid lens
320: second condensing lens 400: driving unit
410: voltage supply module 420: actuator
500: magnification adjustment optical unit 600: wide-angle lens unit
610: fisheye lens 700: intermediate virtual imaging plane (IIP)
800: beam splitting element 900: third condensing lens
1000: detector 1100: controller
1200: MEMS Mirror 1300: scanning lens unit

Claims (9)

a light source for irradiating laser light;
a first condensing lens provided on a path of light irradiated from the light source unit to convert the laser light to be parallel to an optical axis or reduce an angle at which the laser light is emitted;
an optical steering unit in which a lens shift actuator having an objective lens mounted on the optical path converted through the first condensing lens is installed to adjust a position at which the laser light is imaged on an intermediate virtual imaging plane;
a driving unit for driving the optical steering unit;
a magnification adjustment optical unit for forming an image by enlarging or reducing the laser light whose optical path has been changed through the optical steering unit to be positioned on the image plane of the preset wide-angle lens unit; and
and a wide-angle lens unit emitting the laser light passing through the image plane at a preset angle and area to increase the scan area and FOV (Field of View) of the laser light;
The lens shift actuator on which the objective lens is mounted controls the position of the objective lens in two dimensions, up, down, left, and right to control the position of the focus by the objective lens in two dimensions, up, down, left and right, but sequentially changing the scanning optical system .
According to claim 1,
and the optical steering unit includes a second condensing lens capable of adjusting the deflection angle of the incident light by controlling the position of the lens.
3. The method of claim 2,
The driving unit adjusts the position of the second condensing lens in two dimensions, up, down, left, and right to two-dimensionally adjust the image on the intermediate virtual imaging plane.
4. The method of claim 3,
The driving unit includes a two-dimensional VCM (Voice Coil Motor) actuator or a two-dimensional linear actuator, and uses the two-dimensional VCM (Voice Coil Motor) actuator or the two-dimensional linear actuator to adjust the position of the second condensing lens up, down, left, and right 2 A scanning optical system, characterized in that two-dimensionally adjusting the image on the intermediate virtual imaging plane by adjusting it dimensionally.
According to claim 1,
The scanning optical system, characterized in that the wide-angle lens unit comprises a fish-eye lens (Fish Eye Lens).
According to claim 1,
a beam splitter for guiding the laser light reflected from the measurement target to the detector;
a third condensing lens provided between the beam splitter and the detector to collect the beam reflected from the beam splitter and transmit it to the detector;
a detector that receives the reflected light to detect the measurement target; and
The scanning optical system, characterized in that it further comprises a wave plate (Wave Plate) between the first condensing lens and the optical steering unit.
According to claim 1,
The scanning optical system further comprises a controller for controlling the driving unit so that the laser light irradiated from the light source unit can pass through the image plane of the wide-angle lens unit.
8. The method of claim 7,
The controller sets a virtual two-dimensional intermediate image plane (IIP) area so that the laser light can pass through the image plane of the wide-angle lens unit, and the laser light irradiated from the light source unit is a virtual two-dimensional intermediate virtual image plane. A scanning optical system, characterized in that the driving unit is controlled to be projected onto an intermediate image plane (IIP) area.
According to claim 1,
The magnification adjustment optical unit converts the radiation angle of the laser light so that the laser light whose optical path is changed through the optical steering unit is incident parallel to the image plane of the preset wide-angle lens unit and transmits the converted laser light.

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