Light-receiving device and lidar device including same

Abstract

According to an embodiment of the present invention, a lidar device comprises: a light-emitting unit for emitting an optical signal to an object; and a light-receiving unit for receiving the optical signal reflected from the object. The light-receiving unit includes: an image sensor; and a micro lens array disposed on the image sensor. The micro lens array includes: a first surface disposed to face the image sensor; and a second surface opposite to the first surface. A light-blocking layer is disposed on a portion of the second surface.

Description

Optical receiving device and lidar device including the same

[0001] The present invention relates to a light receiving device and a lidar device including the same.

[0002] LiDAR (Light Detection and Ranging) measures the distance to an object or creates a visual representation of it using laser pulses emitted from a light source and reflected back at the target object. LiDAR is applied to a variety of technologies that require three-dimensional imaging. For example, LiDAR can be applied to various fields such as meteorology, aviation, space, and automotive. Recently, LiDAR's role in the autonomous driving field has been rapidly increasing.

[0003] In general, the light emitting part of the lidar generates an output light signal and irradiates it on an object, the light receiving part receives an input light signal reflected from the object, and the information generating part generates information about the object using the input light signal received by the light receiving part.

[0004] Lidar can be broadly categorized into mechanical and fixed lidar. Mechanical lidar can achieve a 360-degree field of view by rotating the light emitter and light receiver. Fixed lidar can be, for example, MEMS (Micro Electro Mechanical System) lidar, flash lidar, or OPA (Optical Phase Array) lidar. In MEMS lidar, the tilt angle of the mirror can be slightly changed by electrical signals. Flash lidar uses an optical flash, and a single large-area laser pulse can illuminate the forward environment. In OPA, an optical phase modulator controls the speed of light passing through the lens, thereby controlling the optical wavefront shape.

[0005] Typically, the light-receiving unit of a mechanical lidar comprises a one-dimensional array of image sensors, which are prone to ghosting due to double reflections. Noise from ghosting can provide the lidar with false information, rather than light reflected from actual objects, which can create phantom images in the point cloud, the object detection result.

[0006] The technical problem to be achieved by the present invention is to provide an optical receiving device with minimized noise due to ghosting and a lidar device including the same.

[0007] A lidar device according to an embodiment of the present invention includes a light emitting unit that irradiates an optical signal to an object, and a light receiving unit that receives an optical signal reflected from the object, wherein the light receiving unit includes an image sensor and a micro lens array arranged on the image sensor, wherein the micro lens array includes a first surface arranged to face the image sensor and a second surface opposite the first surface, and a light blocking layer is arranged on a portion of the second surface.

[0008] The image sensor includes a pixel array, and the first surface of the microlens array includes an effective area including a plurality of microlenses corresponding to the pixel array, a buffer area including a plurality of microlenses arranged to surround the effective area, and a peripheral area arranged to surround the buffer area, and the light blocking layer may be arranged in an area of ​​the second surface opposite the buffer area and the peripheral area.

[0009] The above pixel array includes an m*n pixel array, and the ratio of m to n may be 8 or greater.

[0010] The first surface of the micro lens array includes (m+2a)*(n+2b) micro lenses, wherein a and b are each integers greater than or equal to 1, and the effective area includes m*n micro lenses and can be matched one-to-one with the m*n pixel array.

[0011] The above pixel array may include a 16*2 pixel array, a 32*2 pixel array, a 64*2 pixel array, a 128*2 pixel array, a 256*2 pixel array, a 512*2 pixel array, or a 1024*2 pixel array.

[0012] The above second surface may be a flat surface.

[0013] The thickness of the above light-blocking layer may be 0.05 to 0.2 times the average sag value of the plurality of micro lenses in the effective area.

[0014] The above light-blocking layer may have a light transmittance of 1% or less.

[0015] The above light-blocking layer may include chromium.

[0016] It may further include a plate on which the light emitting unit and the light receiving unit are mounted, and a motor for rotating the plate.

[0017] An optical receiving device according to an embodiment of the present invention includes an image sensor and a micro lens array disposed on the image sensor, wherein the micro lens array includes a first surface disposed to face the image sensor and a second surface opposite the first surface, and a light blocking layer is disposed on a portion of the second surface.

[0018] The image sensor includes a pixel array, and the first surface of the microlens array includes an effective area including a plurality of microlenses corresponding to the pixel array, a buffer area including a plurality of microlenses arranged to surround the effective area, and a peripheral area arranged to surround the buffer area, and the light blocking layer may be arranged in an area of ​​the second surface opposite the buffer area and the peripheral area.

[0019] According to an embodiment of the present invention, a light receiving device and a lidar device including the same can be obtained with minimized noise due to ghosting. By minimizing noise due to ghosting, phantom images can be eliminated, thereby improving the accuracy of object recognition.

[0020] FIG. 1 is a block diagram of a lidar device according to one embodiment of the present invention.

[0021] FIG. 2 is a top view of an image sensor according to an embodiment of the present invention.

[0022] Figure 3 is a bottom view of a micro lens array according to an embodiment of the present invention.

[0023] FIG. 4 is a cross-sectional view along a first direction of an image sensor and a micro lens array according to an embodiment of the present invention.

[0024] FIG. 5 is a cross-sectional view of an image sensor and a micro lens array according to an embodiment of the present invention in a second direction.

[0025] Fig. 6 is a cross-sectional view of a light receiving unit according to an embodiment of the present invention along a first direction.

[0026] FIG. 7 is a cross-sectional view along a first direction of an image sensor and a micro lens array according to another embodiment of the present invention.

[0027] FIG. 8 is a cross-sectional view along a second direction of an image sensor and a micro lens array according to another embodiment of the present invention.

[0028] Figure 9 is a simulation result comparing the amount of light absorbed by an image sensor when a light blocking layer is disposed and when it is not disposed according to an embodiment of the present invention.

[0029] FIG. 10 is a perspective view of a lidar system according to an embodiment of the present invention.

[0030] Figure 11 is an exploded view of a lidar system according to an embodiment of the present invention.

[0031] Figure 12 is an exploded view of a lidar device according to an embodiment of the present invention.

[0032] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0033] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0034] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0035] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0036] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0037] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

[0038] These terms are intended only to distinguish one component from another, and are not intended to limit the nature, order, or sequence of the component.

[0039] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0040] Additionally, when described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0041] The lidar device according to an embodiment of the present invention may refer to a lidar device mounted on a vehicle to measure the distance between the vehicle and an object, but is not limited thereto. The lidar device according to an embodiment of the present invention may extract depth information using the Time of Flight (ToF) principle or the phase shift principle. In this specification, the lidar device may also be referred to as an information generating device, a depth information generating device, or a camera device.

[0042] FIG. 1 is a block diagram of a lidar device according to one embodiment of the present invention.

[0043] Referring to FIG. 1, a lidar device (1000) according to an embodiment of the present invention includes a light emitting unit (100), a light receiving unit (200), an information generating unit (300), and a control unit (400).

[0044] The light emitting unit (100) can generate and output an output light signal in the form of a pulse wave or a continuous wave. The continuous wave may be in the form of a sinusoid wave or a square wave. By generating the output light signal in the form of a pulse wave or a continuous wave, the lidar device (1000) can detect a time difference or a phase difference between the output light signal output from the light emitting unit (100) and the input light signal reflected from the target area and then input to the light receiving unit (200). In this specification, the output light refers to light output from the light emitting unit (100) and incident on an object, and the input light refers to light output from the light emitting unit (100) and reaching the target area, reflected from the target area, and then input to the light receiving unit (200). From the perspective of the target area, the output light may be incident light, and the input light may be reflected light. In this specification, the target area may be used interchangeably with an object or a substance.

[0045] The light emitting unit (100) includes a light source and a lens group.

[0046] A light source generates and outputs a laser pulse. The light source may utilize a light emitting diode (LED), and may have a form in which multiple light emitting diodes are arranged in a certain pattern. Alternatively, the light source may include an organic light emitting diode (OLED) or a laser diode (LD). Alternatively, the light source may be a vertical cavity surface emitting laser (VCSEL). A VCSEL is one of the laser diodes that converts an electrical signal into an optical signal, and can output a wavelength of about 800 to 1000 nm, for example, about 850 nm or about 940 nm. The light source generates an output optical signal in the form of a pulse wave or a continuous wave by repeatedly blinking (on / off) at a certain time interval. The certain time interval may be the frequency of the output optical signal.

[0047] A lens group can collect light output from a light source and output the collected light to the outside. The lens group can be arranged above the light source and spaced apart from the light source. Here, the above of the light source can mean the side from which light is output from the light source. The lens group can include at least one lens, and when the lens group includes a plurality of lenses, each lens can be aligned with respect to a central axis to form an optical system. Here, the central axis can be identical to the optical axis of the optical system. The lens group can also include a diffusion member that receives light output from the light source and then outputs the received light by refracting or diffracting the received light.

[0048] The light receiving unit (200) can receive an optical signal reflected from the target area. At this time, the received optical signal may be an optical signal output by the light emitting unit (100) reflected from the target area.

[0049] The light receiving unit (200) includes an image sensor, a lens group and a filter arranged on the image sensor.

[0050] An optical signal reflected from a target area can pass through a lens group of a light receiving unit (200). The optical axis of the lens group of the light receiving unit (200) can be aligned with the optical axis of an image sensor. A filter can be placed on an optical path between the target area and the image sensor. The filter can filter light having a predetermined wavelength range. The filter can pass light of a specific wavelength. For example, the filter can pass light in an infrared or near-infrared band and block light other than the infrared or near-infrared band. The image sensor can receive an optical signal and output the received optical signal as an electrical signal. The image sensor can detect light of a wavelength corresponding to the wavelength of light output by the light emitting unit (100). For example, the image sensor can detect light in an infrared or near-infrared band.

[0051] An image sensor may be configured with a structure in which multiple pixels are arranged in a grid shape.

[0052] The light receiving unit (200) and the light emitting unit (100) may be arranged side by side. The light receiving unit (200) may be arranged next to the light emitting unit (100). The light receiving unit (200) may be arranged to face the same direction as the light emitting unit (100). Alternatively, the light receiving unit (200) and the light emitting unit (100) may be arranged to face different directions. When the light receiving unit (200) and the light emitting unit (100) are arranged to face different directions, an optical path conversion member may be further arranged between the light receiving unit (200) and the light emitting unit (100).

[0053] The information generating unit (300) generates information about a target area using an input light signal input to the light receiving unit (200). The information about the target area may include three-dimensional information about the target area. For example, the information about the target area may include depth information about the target area or shape information about the target area. For example, the information generating unit (300) may calculate depth information about an object using the flight time it takes for an output light signal output from the light emitting unit (100) to be input to the light receiving unit (200) after being reflected from an object. For example, the information generating unit (300) may calculate a time difference between an output light signal and an input light signal using an electrical signal received by an image sensor, and may calculate a distance between the target area and the LIDAR device (1000) using the calculated time difference. For example, the information generating unit (300) may calculate a phase difference between an output light signal and an input light signal using an electrical signal received from an image sensor, and may calculate a distance between the target area and the LIDAR device (1000) using the calculated phase difference.

[0054] The control unit (400) controls the operation of the light emitting unit (100), the light receiving unit (200), and the information generating unit (300). The information generating unit (300) and the control unit (400) may be implemented in the form of a PCB (printed circuit board). In addition, the information generating unit (300) and the control unit (400) may be implemented in the form of other configurations. Alternatively, the control unit (400) may be included in a terminal or vehicle in which the lidar device (1000) according to an embodiment of the present invention is installed. For example, the control unit (400) may be implemented in the form of an application processor (AP) of a smartphone in which the lidar device (1000) according to an embodiment of the present invention is installed, or in the form of an electronic control unit (ECU) of a vehicle in which the lidar device (1000) according to an embodiment of the present invention is installed.

[0055] The lidar device (1000) according to an embodiment of the present invention may be a mechanical lidar that rotates 360°. To this end, the lidar device (1000) may further include a rotating unit (500). The rotating unit (500) may further include a plate (510) on which a light-emitting unit (100) and a light-receiving unit (200) are mounted, and a motor (520) that rotates the plate (510). Accordingly, the lidar device (1000) may have a 360° FOV.

[0056] FIG. 2 is a top view of an image sensor according to an embodiment of the present invention, FIG. 3 is a bottom view of a micro lens array according to an embodiment of the present invention, FIG. 4 is a cross-sectional view along a first direction of an image sensor and a micro lens array according to an embodiment of the present invention, FIG. 5 is a cross-sectional view along a second direction of an image sensor and a micro lens array according to an embodiment of the present invention, and FIG. 6 is a cross-sectional view along a first direction of a light receiving unit according to an embodiment of the present invention.

[0057] Referring to FIGS. 2 to 6, a light receiving unit (200) included in a lidar device (1000) according to an embodiment of the present invention includes an image sensor (210), a micro lens array (220) disposed on the image sensor (210), a lens group (230) disposed on the micro lens array (220), a filter (240) disposed on the lens group (230), and a window (250) disposed on the filter (240).

[0058] According to an embodiment of the present invention, the image sensor (210) includes a pixel array. Here, the pixel array may be a single photon avalanche detector (SPAD) array, and the SPAD array may include a plurality of SPADs. When the SPAD receives an optical signal, photons may be detected by the avalanche phenomenon.

[0059] Here, the image sensor (210) includes a pixel array arranged along a first direction and a second direction, and the number of pixels arranged along the first direction may be greater than the number of pixels arranged along the second direction. For example, the image sensor (210) according to an embodiment of the present invention includes an m*n pixel array, and m may be greater than n. When the ratio of m to n is 8 or more, it may be referred to as a one-dimensional pixel array or a one-dimensional SPAD array.

[0060] According to an embodiment of the present invention, the image sensor (210) may include a one-dimensional pixel array. For example, the image sensor (210) according to an embodiment of the present invention may include a 16*2 pixel array, a 32*2 pixel array, a 64*2 pixel array, a 128*2 pixel array, a 256*2 pixel array, a 512*2 pixel array, or a 1024*2 pixel array.

[0061] According to an embodiment of the present invention, a micro lens array (220) is arranged on an image sensor (210) so as to be spaced apart from the image sensor (210). The micro lens array (220) includes a first surface (220A) arranged to face the image sensor (210) and a second surface (220B) opposite the first surface (220A), and a plurality of micro lenses protrude from the first surface (220A) to face the image sensor (210). For convenience of explanation, the first surface (220A) of the micro lens array (220) may be referred to as a lower surface of the micro lens array (220), and the second surface (220B) of the micro lens array (220) may be referred to as an upper surface of the micro lens array (220). According to an embodiment of the present invention, a plurality of micro lenses are formed on the first surface (220A) of the micro lens array (220), and the second surface (220B) of the micro lens array (220) may be a flat surface.

[0062] A first surface (220A) of a micro lens array (220) according to an embodiment of the present invention includes an effective area (220A1) including a plurality of micro lenses corresponding to a pixel array of an image sensor (210), a buffer area (220A2) including a plurality of micro lenses arranged to surround the effective area (220A1), and a peripheral area (220A3) arranged to surround the buffer area (220A2).

[0063] Here, the effective area (220A1) can be matched one-to-one with the pixel array. That is, when the image sensor (210) includes an m*n pixel array, the effective area (220A1) includes m*n micro lenses, and the pixels of the image sensor (210) and the micro lenses of the effective area (220A1) can be matched one-to-one. Accordingly, among the optical signals incident on the light receiving unit (200), the optical signals incident on the effective area (220A1) can be detected by the image sensor (210) and used to recognize an object. The optical signals incident on the light receiving unit (200) can be collected by the micro lenses of the effective area (220A1) of the micro lens array (220), thereby increasing the optical reception efficiency for each pixel. Accordingly, the micro lens array (220) may also be referred to as a sensor window.

[0064] Meanwhile, the buffer region (220A2) may be arranged to surround the effective region (220A1) around the effective region (220A1). For example, if the image sensor (210) includes an m*n pixel array and the effective region (220A1) includes m*n micro lenses, the first surface (220A) of the micro lens array (220) may include a total of (m+2a)*(n+2b) micro lenses, including the buffer region (220A2). Here, a and b may be the same or different. For example, a and b may be 1 or more and 10 or less, preferably 1 or more and 5 or less, and more preferably 2 or more and 3 or less. For example, a may be 3 and b may be 2. In this way, if the first surface (220A) of the micro lens array (220) includes a buffer area (220A2) surrounding the effective area (220A1), the light collection efficiency of the effective area (220A1) can be improved and the loss of the optical signal can be reduced.

[0065] Meanwhile, the peripheral region (220A3) may be arranged to surround the buffer region (220A2) around the buffer region (220A2). At this time, the peripheral region (220A3) may be a flat surface. Accordingly, the micro lens array (220) may be attached to a structure within the image sensor (210) or the light receiving unit (200) through the peripheral region (220A3).

[0066] Referring to FIG. 6, a lens group (230), a filter (240), and a window (250) are sequentially arranged on an image sensor (210) and a micro lens array (220). Here, the lens group (230) may include a plurality of lenses. For example, the lens group (230) may include two lenses arranged to be spaced apart from each other, but is not limited thereto. The filter (240) arranged on the lens group (230) may be a bandpass filter. For example, it may be a bandpass filter that transmits only IR light signals among the light signals input to the receiver (200). Although not illustrated, the lens group (230) and the filter (240) may be arranged on a lens barrel. Although the image sensor (210), micro lens array (220), lens group (230), and filter (240) are shown to be arranged sequentially, this is not limited thereto, and the image sensor (210), micro lens array (220), filter (240), and lens group (230) may be arranged in that order.

[0067] The window (250) is positioned outside the lens barrel, and the light signal reflected from the object passes through the window (250) and is sequentially incident on the filter (240), lens group (230), micro lens array (220), and image sensor (210). Accordingly, the window (250) may be referred to as a glass window or an external window. The light signal output from the light emitting unit (100) may also be output to the outside through the window (250).

[0068] Referring again to FIGS. 4 and 5, the micro lens array (220) may be a transparent member. For example, the micro lens array (220) may include a transparent material such as gallium phosphide (GaP), which may increase the efficiency of the image sensor (210). However, stray light may enter through the buffer area (220A2) and the peripheral area (220A3), which are areas outside the effective area (220A1) of the micro lens array (220), and this may cause a ghost phenomenon due to a virtual point cloud.

[0069] According to an embodiment of the present invention, a light blocking layer is placed in a part of a micro lens array (220), thereby minimizing the ghost phenomenon.

[0070] Referring to FIGS. 4 and 5, the micro lens array (220) includes a first surface (220A) arranged to face the image sensor (210) and a second surface (220B) opposite the first surface (220A), and a light blocking layer (225) is arranged on a portion of the second surface (220B). Accordingly, ghosting due to stray light can be minimized.

[0071] Here, the light-blocking layer (225) may mean a layer having a light transmittance of 1% or less, preferably 0.5% or less, and more preferably 0.1% or less. That is, since the light-blocking layer (225) is a layer through which light is not transmitted, light incident on the light-blocking layer (225) does not pass through the micro lens array (220), and thus cannot be incident on the image sensor (210), thereby minimizing the ghost phenomenon caused by stray light.

[0072] Here, the light-blocking layer (225) may include a black material, and the black material may be coated or deposited on a portion of the second surface (220B) of the micro lens array (220). Here, the black material may include, but is not limited to, black chrome, black epoxy resin, black painting, etc.

[0073] According to an embodiment of the present invention, the light blocking layer (225) may be disposed in an area opposite to the buffer area (220A2) and the peripheral area (220A3) of the first surface (220A) of the second surface (220B) of the micro lens array (220). Accordingly, light incident on the area opposite to the buffer area (220A2) and the peripheral area (220A3) of the first surface (220A) of the second surface (220B) of the micro lens array (220) is blocked by the light blocking layer (225) and thus cannot be incident on the image sensor (210), and only light incident on the effective area (220A1) of the first surface (220A) of the second surface (220B) of the micro lens array (220) can pass through the micro lens array (220) and be incident on the image sensor (210). According to this, the possibility of ghost images being generated due to stray light entering the image sensor (210) can be reduced.

[0074] According to an embodiment of the present invention, the thickness (T) of the light-blocking layer (225) may be 0.05 to 0.2 times, preferably 0.05 to 0.15 times, and more preferably 0.075 to 0.125 times, the average sag value of the plurality of micro lenses arranged in the effective area (220A1) of the micro lens array (220). Here, the sag value may mean the sagittal depth of the micro lenses. For example, when the average sag value of the plurality of micro lenses arranged in the effective area (220A1) of the micro lens array (220) is 3 µm, the thickness of the light-blocking layer (225) may be 150 nm to 600 nm, preferably 150 nm to 450 nm, and more preferably 225 nm to 375 nm. If the thickness (T) of the light-blocking layer (225) is less than the lower limit of this numerical range, the light-blocking effect is low, so that stray light may enter the image sensor (210). If the thickness (T) of the light-blocking layer (225) exceeds this numerical range, the amount of light incident on the effective area (220A1) of the micro-lens array (220) is reduced, so that the object recognition accuracy of the image sensor (210) may be lowered.

[0075] Fig. 7 is a cross-sectional view along a first direction of an image sensor and a microlens array according to another embodiment of the present invention, and Fig. 8 is a cross-sectional view along a second direction of an image sensor and a microlens array according to another embodiment of the present invention. Contents overlapping with those described with reference to Figs. 1 to 6 are omitted for convenience of explanation.

[0076] Referring to FIGS. 7 and 8, the light-blocking layer (225) may be disposed in an area opposite to the buffer area (220A2) and the peripheral area (220A3) of the first surface (220A) of the second surface (220B) of the micro lens array (220). At this time, the thickness of the light-blocking layer (225) disposed in a part of the area opposite to the buffer area (220A2) may be different from the thickness of the light-blocking layer (225) disposed in a part of the area opposite to the peripheral area (220A3). For example, the thickness of the light-blocking layer (225) disposed in a part of the area opposite to the buffer area (220A2) may be thinner than the thickness of the light-blocking layer (225) disposed in a part of the area opposite to the peripheral area (220A3). As illustrated, the light-blocking layer (225) disposed in an area opposite to the buffer area (220A2) may include an area whose thickness becomes thinner as it approaches the boundary between the buffer area (220A2) and the effective area (220A1). Accordingly, the problem of the amount of light incident on the effective area (220A1) of the micro lens array (220) being reduced due to the height of the light-blocking layer (225) can be prevented, and the object recognition accuracy of the image sensor (210) can be improved.

[0077] FIG. 9 and Table 1 are simulation results comparing the amount of light absorbed by an image sensor when a light blocking layer is disposed and when it is not disposed according to an embodiment of the present invention.

[0078] Light blocking layer Matte blocking layer Total light per pixel 0.4682 0.4582 Ghost light per pixel 0.0287 0.0194 Ghost light to total light ratio 6.13% 4.23%

[0079] Referring to FIG. 9 and Table 1, for an image sensor including a 4*2 pixel array, each pixel having a size of 8㎛*8㎛, the total light quantity and ghost light quantity were compared depending on the presence or absence of a light-blocking layer. Here, when the light-blocking layer is not arranged on the micro-lens array, the total light quantity incident on one pixel is 0.4682, of which the ghost light quantity is 0.0287, and accordingly, the ratio of the ghost light quantity to the total light quantity is 6.13%. Here, the ghost light quantity may also be referred to as an unwanted light quantity.

[0080] In contrast, when a light blocking layer is placed on a micro lens array, the total amount of light incident on one pixel is 0.4582, of which the amount of ghost light is 0.0194, and accordingly, the ratio of the amount of ghost light to the total amount of light is 4.23%.

[0081] In this way, it can be seen that when a light blocking layer is arranged on a micro lens array according to an embodiment of the present invention, the ratio of ghost light to total light is significantly reduced.

[0082] FIG. 10 is a perspective view of a lidar system according to an embodiment of the present invention, FIG. 11 is an exploded view of a lidar system according to an embodiment of the present invention, and FIG. 12 is an exploded view of a lidar device according to an embodiment of the present invention.

[0083] Referring to FIGS. 10 to 12, the light emitting unit (100) and the light receiving unit (200) may be accommodated within a housing (50) of a lidar system (1200). As illustrated, one lidar system (1200) may include a plurality of lidar devices (1000). For example, each lidar device (1000) included within one lidar system (1200) may include a light emitting unit (100) and a light receiving unit (200), and the two lidar devices (1000) may be arranged to face opposite directions. One of the two lidar devices may be a mid-range lidar device, and the other may be a long-range lidar device.

[0084] A plurality of openings may be formed in the housing (50). Among the plurality of openings, a first opening (51) may be arranged to correspond to a window (250) of a lidar device (1000) and may serve as a passage for light emission and light reception. Among the plurality of openings, a second opening (52) may serve as a passage for dissipating heat generated from a lidar device (1000) housed within the housing (50).

[0085] The number of first openings (51) may be less than the number of second openings (52), and the diameter of the first opening (51) may be greater than the diameter of the second opening (52). Since the first openings (51) are arranged to correspond to the windows (250) of the lidar device (1000), the number of first openings (51) formed in the housing (50) may be equal to the number of lidar devices (1000) accommodated in the housing (50).

[0086] Each lidar device (1000) includes a light emitting unit (100) and a light receiving unit (200), and for this purpose, each lidar device (1000) may further include a mount (600) on which the light emitting unit (100) and the light receiving unit (200) are mounted. The light emitting unit (100) is placed on the side of the light receiving unit (200), and both light emitted from the light emitting unit (100) and light reflected from an object and then incident on the light receiving unit (200) can pass through the window (250).

[0087] Although not specifically illustrated, the light emitting unit may include a substrate, a light source, an optical member, a shield member, and a diffusion member. The substrate may include a printed circuit board (PCB). The substrate may also be connected to a connector via an FPCB. The light source is disposed on the substrate, and the substrate may include a terminal. The light source may correspond to the light source of the light emitting unit (200) described above. That is, the light source may include a plurality of emitters arranged in an array shape. The plurality of emitters may be arranged in an m*n matrix so that the light receiving unit (200) may correspond to a pixel array of the image sensor (210), but is not limited thereto. The driving of the plurality of emitters may be individually controlled or integratedly controlled. The optical member may collect light emitted from the light source or convert an optical path of light emitted from the light source. For example, when the light source is not arranged to face the window (250), the optical member can change the optical path so that the light emitted from the light source is emitted through the window (250). Alternatively, the light source may be an edge emitting laser diode (EEL). The shield member surrounds the substrate and the light source, may be referred to as a cover can, may be non-magnetic, and thus may block electromagnetic interference (EMI). The diffusion member may be a diffuser lens or a homogenizer. The diffusion member may be arranged on the optical path of the light emitted from the light source.

[0088] The light receiving unit (200) may include a sensor unit and a lens unit. The sensor unit may include a substrate, an image sensor (210) disposed on the substrate, and a micro lens array disposed on the image sensor (210). The image sensor (210) may detect infrared or near-infrared light. The image sensor (210) may detect light of a specific wavelength among infrared or near-infrared light. The lens unit may include a lens barrel, a plurality of lenses, a filter, and a lens hood. The image sensor (210) may detect light passing through the filter. The image sensor (210) may detect light in the wavelength band of the light source. Through this, the image sensor (210) may detect light emitted from the light source and reflected on the subject, thereby sensing 3D image information of the subject.

[0089] As described above, the lidar device according to an embodiment of the present invention may be a mechanical lidar device. Accordingly, the lidar device according to an embodiment of the present invention may be designed to rotate 360 ​​degrees by a motor.

[0090] Although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be construed as being included within the scope of the present invention defined in the appended claims.

Claims

1. A light emitting part that irradiates a light signal to an object, and Includes a light receiving unit that receives a light signal reflected from the object, The above light receiving unit, Image sensor, and A micro lens array disposed on the image sensor, The above micro lens array, It includes a first surface arranged to face the image sensor and a second surface opposite to the first surface, A lidar device having a light-blocking layer disposed on a portion of the second surface.

2. In paragraph 1, The image sensor includes a pixel array, The first surface of the above micro lens array is, An effective area including a plurality of micro lenses corresponding to the above pixel array, A buffer region comprising a plurality of micro lenses arranged to surround the effective area, and Includes a peripheral area arranged to surround the above buffer area, A lidar device in which the above light-blocking layer is disposed in an area opposite to the buffer area and the peripheral area among the second surfaces.

3. In paragraph 2, A lidar device wherein the pixel array includes an m*n pixel array, and a ratio of m to n is 8 or more.

4. In paragraph 3, The first surface of the microlens array includes (m+2a)*(n+2b) microlenses, The above a and the above b are each integers greater than or equal to 1, A lidar device having an effective area including m*n micro lenses and one-to-one matching with the m*n pixel array.

5. In paragraph 2, A lidar device wherein the pixel array includes a 16*2 pixel array, a 32*2 pixel array, a 64*2 pixel array, a 128*2 pixel array, a 256*2 pixel array, a 512*2 pixel array or a 1024*2 pixel array.

6. In paragraph 2, The above second surface is a flat surface lidar device.

7. In paragraph 2, A lidar device in which the thickness of the above light-blocking layer is 0.05 to 0.2 times the average sag value of a plurality of micro lenses in the effective area.

8. In paragraph 1, A lidar device having the above light-blocking layer having a light transmittance of 1% or less.

9. In paragraph 1, A lidar device wherein the above light-blocking layer comprises chromium.

10. In paragraph 1, A plate mounting the light emitting unit and the light receiving unit, and A lidar device further comprising a motor for rotating the above plate.

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