Light beam deflection device and laser radar

Abstract

The invention discloses a light beam deflection device and a laser radar. The light beam deflection device comprises a light beam deflection structure, the light beam deflection structure comprises a liquid crystal variable wave plate and a liquid crystal polarization grating, the liquid crystal variable wave plate comprises a first liquid crystal layer and a first driver configured to drive the first liquid crystal layer, and the first liquid crystal layer comprises a first state and a second state. In the first state, the liquid crystal variable wave plate changes the polarization state of the light, in the second state, the liquid crystal variable wave plate does not change the polarization state of the light, the liquid crystal polarization grating comprises a second liquid crystal layer, the second liquid crystal layer comprises a third state, and in the third state, the liquid crystal polarization grating changes the polarization state of the light and changes the deflection angle of the light. The light beam deflection structure comprises first light beam deflection structures, liquid crystal polarization gratings of the first light beam deflection structures enable light to deflect in a first plane, the light beam deflection device comprises a plurality of first light beam deflection structures, and the plurality of first light beam deflection structures are arranged along a first direction, so that light with different deflection directions and deflection angles can be obtained.

Description

Beam deflection devices and lidar Technical Field

[0001] Embodiments of the present disclosure relate to a beam deflecting device and a laser radar. Background Art

[0002] Beam deflection technology dynamically and precisely controls the direction of an emitted laser beam. It has broad application prospects in a wide range of fields, including autonomous driving, intelligent robotics, automated logistics, and urban mapping.

[0003] LiDAR is a radar system that uses laser beams to detect target characteristics such as position and speed. It operates by transmitting a detection signal toward a target and then comparing the received signal reflected from the target with the transmitted signal. After appropriate processing, it can obtain relevant target information, such as target distance, direction, altitude, speed, attitude, and even shape, allowing it to detect, track, and identify the target.

[0004] Summary of the Invention

[0005] The embodiment of the present disclosure provides a light beam deflection device. By setting multiple first liquid crystal layer states, light passing through multiple first beam deflection structures can be combined into multiple different deflection directions and deflection angles, thereby obtaining light with multiple different deflection directions and deflection angles.

[0006] At least one embodiment of the present disclosure provides a light beam deflecting device having a first side and a second side opposite to each other in a first direction, including a light beam deflecting structure, the light beam deflecting structure comprising: a liquid crystal variable wave plate comprising a first liquid crystal layer and a first driver, the first liquid crystal layer comprising a first state and a second state, the first driver being configured to drive the first liquid crystal layer so that the first liquid crystal layer is in the first state or the second state, wherein in the first state, the liquid crystal variable wave plate is configured to change light in a first polarization state into light in a second polarization state or change light in the second polarization state into light in the first polarization state, and in the second state, the liquid crystal variable wave plate is configured not to change the polarization state of light; and a liquid crystal polarization grating disposed on a side of the liquid crystal variable wave plate away from the first side, comprising a second liquid crystal layer, the second liquid crystal layer comprising a third state, wherein in the third state, the liquid crystal polarization grating is configured to change light in the first polarization state into light in the second polarization state and deflect the light in a first deflection direction by a set angle, or change light in the second polarization state into light in the first polarization state. and deflecting the light toward a second deflection direction by the set angle, the first deflection direction and the second deflection direction being symmetrical with respect to the propagation direction of the light, the beam deflecting structure comprising a first beam deflecting structure, the first deflection direction and the second deflection direction of the liquid crystal polarization grating in the first beam deflecting structure being located within a first plane where the first direction and the second direction are located, and the second direction being perpendicular to the first direction; the beam deflecting device comprising a plurality of the first beam deflecting structures, the plurality of the first beam deflecting structures being arranged along the first direction;

[0007] For example, in the beam deflection device provided in an embodiment of the present disclosure, the periodic arrangement direction of the liquid crystal directors of the second liquid crystal layer of the liquid crystal polarization grating in the first beam deflection structure is the second direction;

[0008] For example, in the light beam deflection device provided in an embodiment of the present disclosure, the first deflection state is a right-handed circular polarization state, and the second polarization state is a left-handed circular polarization state;

[0009] For example, in an optical beam deflection device provided in an embodiment of the present disclosure, the liquid crystal polarization grating further includes a second driver, the second liquid crystal layer further includes a fourth state, the second driver is configured to drive the second liquid crystal layer so that the second liquid crystal layer is in the third state or the fourth state, and in the fourth state, the liquid crystal polarization grating is configured not to change the polarization state of light and the deflection angle of light;

[0010] For example, in the beam deflecting device provided in one embodiment of the present disclosure, the values ​​of the multiple setting angles of the multiple first beam deflecting structures are different;

[0011] For example, in the light beam deflection device provided in one embodiment of the present disclosure, the values ​​of the plurality of set angles are in an arithmetic progression or a geometric progression;

[0012] For example, in the beam deflecting device provided in an embodiment of the present disclosure, the plurality of first beam deflecting structures include four first beam deflecting structures, and the four setting angles of the four first beam deflecting structures are 5 degrees, 10 degrees, 15 degrees, and 20 degrees, respectively;

[0013] For example, in the beam deflection device provided in an embodiment of the present disclosure, the plurality of first beam deflection structures include four first beam deflection structures, and the setting angles of the liquid crystal polarization gratings of the four first beam deflection structures are 5 degrees, 10 degrees, 20 degrees, and 20 degrees, respectively;

[0014] For example, in the beam deflection device provided in an embodiment of the present disclosure, the beam deflection structure further includes a second beam deflection structure, wherein the first deflection direction and the second deflection direction of the liquid crystal polarization grating in the second beam deflection structure are located in a second plane where the first direction and the third direction are located, and the third direction is perpendicular to both the first direction and the second direction;

[0015] The beam deflecting device includes at least one second beam deflecting structure, and the plurality of first beam deflecting structures and the at least one second beam deflecting structure are arranged along the first direction;

[0016] For example, in the beam deflecting device provided in an embodiment of the present disclosure, the at least one second beam deflecting structure is located on a side of the plurality of first beam deflecting structures away from the first side or away from the second side;

[0017] For example, in the beam deflection device provided in an embodiment of the present disclosure, the periodic arrangement direction of the liquid crystal directors of the second liquid crystal layer in the second beam deflection structure is the third direction;

[0018] For example, in the beam deflecting device provided in an embodiment of the present disclosure, the beam deflecting device includes a plurality of second beam deflecting structures, and the plurality of second beam deflecting structures are arranged along the first direction;

[0019] For example, in an embodiment of the present disclosure, the beam deflection device includes four first beam deflection structures and two second beam deflection structures. The setting angles of the liquid crystal polarization gratings of the four first beam deflection structures are 5 degrees, 10 degrees, 20 degrees, and 20 degrees, respectively. The setting angles of the two second beam deflection structures are 10 degrees and 20 degrees, respectively.

[0020] For example, in the light beam deflection device provided in an embodiment of the present disclosure, the liquid crystal variable wave plate further includes: a first substrate; a second substrate disposed opposite to the first substrate, the first liquid crystal layer being located between the first substrate and the second substrate; a first alignment layer being located between the first liquid crystal layer and the first substrate; a second alignment layer being located between the first liquid crystal layer and the second substrate; a first transparent conductive layer being located between the first alignment layer and the first substrate; and a second transparent conductive layer being located between the second alignment layer and the second substrate; the first driver including the first transparent conductive layer and the second transparent conductive layer; when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a first voltage, the first liquid crystal layer is in the first state; and when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a second voltage, the first liquid crystal layer is in the second state;

[0021] For example, in the light beam deflecting device provided in one embodiment of the present disclosure, the first liquid crystal layer includes nematic liquid crystal or ferroelectric liquid crystal;

[0022] For example, in the light beam deflection device provided in one embodiment of the present disclosure, the liquid crystal variable wave plate further includes: a first anti-reflection and anti-reflection film located on a side of the first substrate away from the first transparent conductive layer; and a second anti-reflection and anti-reflection film located on a side of the second substrate away from the second transparent conductive layer;

[0023] For example, in the light beam deflection device provided in an embodiment of the present disclosure, the liquid crystal variable wave plate further includes: a first substrate; a second substrate disposed opposite to the first substrate, the first liquid crystal layer being located between the first substrate and the second substrate; a first alignment layer being located between the first liquid crystal layer and the first substrate; a second alignment layer being located between the first liquid crystal layer and the second substrate; a first transparent conductive layer being located between the first alignment layer and the first substrate; a second transparent conductive layer being located between the second alignment layer and the second substrate; a first quarter wave plate being located on a side of the first substrate close to the first side; and a second quarter wave plate being located on a side of the second substrate away from the first side, the first driver including the first transparent conductive layer and the second transparent conductive layer, when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a first voltage, the first liquid crystal layer is in the first state, and when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a second voltage, the first liquid crystal layer is in the second state.

[0024] For example, in the light beam deflecting device provided in one embodiment of the present disclosure, the first liquid crystal layer includes twisted phase liquid crystal;

[0025] For example, in a beam deflection device provided in an embodiment of the present disclosure, the liquid crystal polarization grating includes: a third substrate; a fourth substrate disposed opposite to the third substrate, with the second liquid crystal layer located between the third substrate and the fourth substrate; a third alignment layer located between the second liquid crystal layer and the third substrate; and a fourth alignment layer located between the second liquid crystal layer and the fourth substrate.

[0026] For example, in the beam deflecting device provided in one embodiment of the present disclosure, the second substrate is located on a side of the first substrate away from the first side, the fourth substrate is located on a side of the third substrate away from the first side, and the second substrate and the third substrate are the same substrate;

[0027] For example, in a light beam deflection device provided in an embodiment of the present disclosure, the liquid crystal polarization grating includes: a third substrate; a fourth substrate disposed opposite to the third substrate, a second liquid crystal layer located between the third substrate and the fourth substrate; a third alignment layer located between the second liquid crystal layer and the third substrate; a fourth alignment layer located between the second liquid crystal layer and the fourth substrate; a third transparent conductive layer located between the third alignment layer and the third substrate; and a fourth transparent conductive layer located between the fourth alignment layer and the fourth substrate; the second driver includes the third transparent conductive layer and the fourth transparent conductive layer; when the voltage signal between the third transparent conductive layer and the fourth transparent conductive layer is a third voltage, the second liquid crystal layer is in the third state; and when the voltage signal between the third transparent conductive layer and the fourth transparent conductive layer is a fourth voltage, the second liquid crystal layer is in the fourth state;

[0028] For example, the beam deflection device provided in one embodiment of the present disclosure further includes: a controller, communicatively connected to the plurality of first drivers of the plurality of first beam deflection structures, and configured to provide a voltage signal to the first drivers to place the first liquid crystal layer in the first state or the second state;

[0029] At least one embodiment of the present disclosure provides a laser radar, including a laser emission system, the laser emission system including a plurality of lasers and any one of the above-mentioned beam deflection devices, the plurality of lasers being arranged corresponding to the beam deflection device, the plurality of lasers being located on a first side of the beam deflection device and being configured to emit a beam toward the beam deflection device;

[0030] For example, the laser radar provided in one embodiment of the present disclosure further includes a laser receiving system, including a plurality of detectors, wherein the plurality of detectors are configured to receive light beams; and

[0031] For example, in the laser radar provided in one embodiment of the present disclosure, the laser receiving system also includes the beam deflecting device, which is arranged corresponding to the multiple detectors, and the multiple detectors are located on the first side of the beam deflecting device, and the multiple detectors are configured to receive light beams from the beam deflecting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0033] FIG1 is a side view schematic diagram of a light beam deflection device provided by one embodiment of the present disclosure;

[0034] FIG2 is a schematic front view of the light beam deflection device shown in FIG1 ;

[0035] FIG3 is a schematic diagram of the optical path of the light beam deflection device shown in FIG1 ;

[0036] FIG4 is a side view schematic diagram of another light beam deflecting device provided by an embodiment of the present disclosure;

[0037] FIG5 is a diagram showing the corresponding relationship between the state of the first liquid crystal layer and the deflection angle of the outgoing light of the light beam deflecting device shown in FIG4;

[0038] FIG6 is a side view schematic diagram of another light beam deflecting device provided by an embodiment of the present disclosure;

[0039] FIG7 is a diagram showing the corresponding relationship between the state of the first liquid crystal layer and the deflection angle of the outgoing light of the light beam deflecting device shown in FIG6;

[0040] FIG8 is a numerical diagram of the deflection angle of the outgoing light obtained by the beam deflecting device shown in FIG6 ;

[0041] FIG9 is a schematic side view of another light beam deflecting device provided by an embodiment of the present disclosure;

[0042] 10 is a diagram showing the corresponding relationship between the first liquid crystal layer state, the second liquid crystal layer state, and the deflection angle of the emitted light of the light beam deflecting device shown in FIG. 4 ;

[0043] FIG11 is a diagram showing the corresponding relationship between the first liquid crystal layer state, the second liquid crystal layer state, and the deflection angle of the emitted light of the light beam deflecting device shown in FIG6 ;

[0044] FIG12A is a schematic structural diagram of another beam deflection structure provided by an embodiment of the present disclosure;

[0045] FIG12B is a schematic front view of a liquid crystal polarization grating in the second beam deflection structure shown in FIG12A;

[0046] FIG13 is a schematic structural diagram of a liquid crystal variable wave plate provided by an embodiment of the present disclosure;

[0047] FIG14 is a schematic diagram of a liquid crystal variable wave plate provided by an embodiment of the present disclosure in a state where a first voltage is applied;

[0048] Figures 15 and 16 are simulation diagrams of the light beam in the state shown in Figure 14;

[0049] FIG17 is a schematic diagram showing a state where a second voltage is applied to the liquid crystal variable wave plate shown in FIG14 ;

[0050] 18 and 19 are simulation diagrams of the light beam in the state shown in FIG17;

[0051] FIG20 is a diagram showing a state of a first liquid crystal layer of another liquid crystal variable wave plate provided by an embodiment of the present disclosure after a first voltage is applied;

[0052] FIG21 is a diagram showing a state of the first liquid crystal layer after a second voltage is applied to the liquid crystal variable wave plate shown in FIG20 ;

[0053] FIG22 is a schematic diagram of another liquid crystal variable wave plate provided by an embodiment of the present disclosure in a state where a first voltage is applied;

[0054] FIG23 is a schematic diagram showing a state where a second voltage is applied to the liquid crystal variable wave plate shown in FIG22 ;

[0055] FIG24 is a schematic side view of a liquid crystal polarization grating provided in one embodiment of the present disclosure;

[0056] FIG25 is a schematic top view of the second liquid crystal layer of the liquid crystal polarization grating shown in FIG24 ;

[0057] FIG26 is a schematic diagram of another liquid crystal polarization grating according to an embodiment of the present disclosure in a state where a third voltage is applied;

[0058] FIG27 is a schematic diagram of a state where a fourth voltage is applied to the liquid crystal polarization grating shown in FIG26 ;

[0059] 28 to 35 are beam simulation diagrams of different grating periods under the state shown in FIG. 26 ;

[0060] FIG36 is a schematic structural diagram of a beam deflection structure provided by an embodiment of the present disclosure;

[0061] 37 and 38 are schematic diagrams of beam deflection of the beam deflection structure shown in FIG36 ;

[0062] FIG39 is a schematic structural diagram of another beam deflection structure provided by an embodiment of the present disclosure;

[0063] 40 to 42 are schematic diagrams of beam deflection of the beam deflection structure shown in FIG39 ;

[0064] FIG43 is a graph showing the voltage state of the first liquid crystal layer of the light beam deflecting device shown in FIG4 and the corresponding deflection angle of the outgoing light;

[0065] FIG44 is a graph showing the voltage state of the liquid crystal layer of the light beam deflection device shown in FIG4 and the corresponding deflection angle of the outgoing light;

[0066] FIG45 is a graph showing the voltage state of the first liquid crystal layer of the light beam deflecting device shown in FIG6 and the corresponding deflection angle of the outgoing light;

[0067] FIG46 is a diagram showing the voltage state of the liquid crystal layer of the light beam deflection device shown in FIG6 and the corresponding deflection angle of the output light;

[0068] FIG47 is a schematic diagram of another light beam deflecting device provided by an embodiment of the present disclosure;

[0069] FIG48 is a flow chart of a process for preparing a liquid crystal variable wave plate according to an embodiment of the present disclosure;

[0070] FIG49 is a flow chart of a process for preparing a passive liquid crystal polarization grating according to an embodiment of the present disclosure;

[0071] FIG50 is a flow chart of a process for preparing an active liquid crystal polarization grating according to an embodiment of the present disclosure;

[0072] FIG51 is a schematic structural diagram of a laser emission system of a laser radar provided in one embodiment of the present disclosure;

[0073] FIG52 is a schematic structural diagram of a laser receiving system provided by an embodiment of the present disclosure;

[0074] FIG53 is a schematic structural diagram of another laser receiving system provided by an embodiment of the present disclosure; and

[0075] Figure 54 is a workflow diagram of a laser radar provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0076] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0077] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0078] Unless otherwise defined, the features such as "parallel", "perpendicular" and "same" used in the embodiments of the present disclosure include the cases of "parallel", "perpendicular", "same" in a strict sense, as well as the cases of "approximately parallel", "approximately perpendicular", "approximately the same" and the like which contain certain errors. For example, the above-mentioned "approximately" may mean that the difference between the compared objects is 10% of the average value of the compared objects, or within 5%. When the number of a component or element is not specifically indicated below in the embodiments of the present disclosure, it means that the component or element may be one or more, or may be understood as at least one. "At least one" refers to one or more, and "multiple" refers to at least two. The "same-layer arrangement" in the embodiments of the present disclosure refers to the relationship between multiple film layers formed by the same material after the same step (for example, a one-step patterning process). The "same layer" here does not always mean that the thickness of multiple film layers is the same or the height of multiple film layers in the cross-sectional view is the same.

[0079] Liquid crystal polarization gratings use the periodic arrangement of liquid crystal directors to adjust the polarization state of incident light and achieve light splitting. Taking the periodic distribution of directors along the X-axis as an example, the directors of liquid crystal molecules can be described as:

[0080] Where Λ is the period of the liquid crystal polarization grating, and α0 is the initial azimuth angle of the liquid crystal.

[0081] The transmittance T of the liquid crystal polarization grating is described using the Jones matrix:

[0082] Among them, the rotation matrix is the dynamic phase of light in liquid crystal, transmittance T:

[0083] Calculate the diffraction angle using the grating equation: Where λ is the wavelength of the incident light and Λ is the period of the liquid crystal polarization grating. Therefore, by changing the period of the liquid crystal polarization grating, liquid crystal polarization gratings with different deflection angles can be prepared.

[0084] Wave plates, also known as phase retarders, create a phase shift between two mutually orthogonal polarization components passing through the wave plate, thereby adjusting the polarization state of a light beam. Wave plates are transparent plates with a specific birefringence and are typically used to control the polarization state of a light beam. For example, a half-wave plate is a plate that creates a path length difference of 1 / 2 wavelength between ordinary light (o light) and extraordinary light (e light). Left-handed circularly polarized light passing through a half-wave plate becomes right-handed circularly polarized light, and right-handed circularly polarized light passing through a half-wave plate becomes left-handed circularly polarized light.

[0085] Common wave plates in optical components are made of quartz crystals, calcite (CaCO3), magnesium fluoride (MgF2), sapphire (Al2O3), mica and some birefringent polymers, but common wave plates are fixed wave plates and cannot achieve switching between multiple polarizations.

[0086] The embodiments of the present disclosure provide a beam deflection device and a laser radar. The beam deflection device has a light input side and a light output side relative to each other in a first direction. The beam deflection device includes a beam deflection structure, and the beam deflection structure includes a liquid crystal variable wave plate and a liquid crystal polarization grating. The liquid crystal variable wave plate includes a first liquid crystal layer and a first driver. The first liquid crystal layer includes a first state and a second state. The first driver is configured to drive the first liquid crystal layer so that the first liquid crystal layer is in the first state or the second state. The first liquid crystal layer is in the first state. The liquid crystal variable wave plate is configured to change light in the first polarization state to light in the second polarization state or change light in the second polarization state to light in the first polarization state. The first liquid crystal layer is in the second state. The liquid crystal variable wave plate is configured not to change the polarization state of the light. The liquid crystal polarization grating is disposed on a side of the liquid crystal variable wave plate away from the light incident side and includes a second liquid crystal layer. The second liquid crystal layer includes a third state. In the third state, the liquid crystal polarization grating is configured to convert light in a first polarization state into light in a second polarization state and deflect the light in a first deflection direction at a set angle, or to convert light in a second polarization state into light in a first polarization state and deflect the light in a second deflection direction at a set angle. The first deflection direction and the second deflection direction are symmetrical about the propagation direction of the light. The beam deflection structure includes a first beam deflection structure. The first and second deflection directions of the liquid crystal polarization grating in the first beam deflection structure are located in a first plane where the first and second directions are located, and the second direction is perpendicular to the first direction. The beam deflection device includes multiple first beam deflection structures, and the multiple first beam deflection structures are arranged along the first direction.

[0087] In the beam deflection device provided in the embodiments of the present disclosure, light enters the beam deflection device from a first side and exits from a second side of the beam deflection device. A liquid crystal variable wave plate can change the polarization state of the light, and a liquid crystal polarization grating can change the deflection direction and angle of the light according to the polarization state of the incident light. A liquid crystal variable wave plate is disposed on the first side of the liquid crystal polarization grating. By setting the state of the first liquid crystal layer of the liquid crystal variable wave plate, the polarization state of the light entering the liquid crystal polarization grating can be set, and thus the deflection direction and angle of the light can be set. Multiple first beam deflection structures are disposed along a first direction. By setting the state of the first liquid crystal layer of the liquid crystal variable wave plate of each first beam deflection structure, the deflection direction and angle of the light within the first plane after passing through each first beam deflection structure can be set. Light passing through multiple first beam deflection structures can be combined to produce a variety of different deflection directions and angles, thereby producing light with a variety of different deflection directions and angles. For example, by setting the state of the first liquid crystal layer of the liquid crystal variable wave plate of multiple first beam deflection structures, light can be deflected along the first deflection direction or the second deflection direction within the first plane after passing through each first beam deflection structure. Thus, after passing through the multiple first beam deflection structures, light with a maximum deflection angle along the first deflection direction or a maximum deflection angle along the second deflection direction can be obtained, with the maximum deflection angle being equal to the sum of the set angles of the multiple first beam deflection structures. Therefore, this beam deflection device can not only obtain light with a maximum deflection angle, but also obtain light with multiple different deflection angles, thereby achieving beam scanning and enabling one-dimensional scanning of the beam within the first plane.

[0088] Below, the beam deflection device and laser radar provided in the embodiments of the present disclosure are described in detail with reference to the accompanying drawings.

[0089] An embodiment of the present disclosure provides a light beam deflection device. FIG1 is a side view schematic diagram of a light beam deflection device provided in an embodiment of the present disclosure; FIG2 is a front view schematic diagram of the light beam deflection device shown in FIG1; and FIG3 is a light path schematic diagram of the light beam deflection device shown in FIG1. ​​As shown in FIG1 to FIG3, the light beam deflection device 100 includes a light beam deflection structure 110, and the light beam deflection structure 110 includes a liquid crystal variable wave plate 111 and a liquid crystal polarization grating 112. The liquid crystal variable wave plate 111 includes a first liquid crystal layer 1110 and a first driver. The first liquid crystal layer 1110 includes a first state S1 and a second state S2. The first driver is configured to drive the first liquid crystal layer 1110 so that the first liquid crystal layer 1110 is in the first state S1 or the second state S2. When the first liquid crystal layer 1110 is in the first state S1, the liquid crystal variable wave plate 111 is configured to convert light in a first polarization state into light in a second polarization state or convert light in a second polarization state into light in the first polarization state. When the first liquid crystal layer 1110 is in the second state S2, the liquid crystal variable wave plate 111 is configured to not change the polarization state of light. For example, when the first liquid crystal layer 1110 is in the first state S1, the liquid crystal variable wave plate 111 functions as a half-wave plate; when the first liquid crystal layer 1110 is in the second state S2, the liquid crystal variable wave plate 111 functions as a full-wave plate. The liquid crystal polarization grating 112 is disposed on a side of the liquid crystal variable wave plate 111 away from the first side E1. The liquid crystal polarization grating 112 includes a second liquid crystal layer 1120. The second liquid crystal layer 1120 is in the third state S3. When the second liquid crystal layer 1120 is in the third state S3, the liquid crystal polarization grating 112 is configured to convert light in the first polarization state into light in the second polarization state and deflect the light in a first deflection direction by a set angle, or to convert light in the second polarization state into light in the first polarization state and deflect the light in a second deflection direction by a set angle. The first deflection direction and the second deflection direction are symmetrical about the propagation direction of light.

[0090] The beam deflection structure 110 includes a first beam deflection structure 1101. The first deflection direction and the second deflection direction of the liquid crystal polarization grating 112 in the first beam deflection structure 1101 are located in a first plane where the first direction X and the second direction Y are located. The second direction Y is perpendicular to the first direction X. The beam deflection device 100 includes a plurality of first beam deflection structures 1101, which are arranged along the first direction X.

[0091] In the light beam deflection device 100 provided in the embodiments of the present disclosure, light enters the light beam deflection device 100 from a first side E1 and exits from a second side E2 of the light beam deflection device 100. A liquid crystal variable wave plate 111 can change the polarization state of the light, and a liquid crystal polarization grating 112 can change the deflection direction and angle of the light according to the polarization state of the incident light. The liquid crystal variable wave plate 111 is disposed on the first side E1 of the liquid crystal polarization grating 112. By adjusting the state of the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111, the polarization state of the light entering the liquid crystal polarization grating 112 can be set, and thus the deflection direction and angle of the light can be set. Multiple first beam deflection structures 1101 are arranged along the first direction X. By setting the state of the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111 of each first beam deflection structure 1101, the deflection direction and deflection angle of the light in the first plane after passing through each first beam deflection structure 1101 can be set. After passing through multiple first beam deflection structures 1101, a variety of different deflection directions and deflection angles can be combined, thereby obtaining light with a variety of different deflection directions and deflection angles.

[0092] For example, by setting the state of the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111 of multiple first beam deflection structures 1101, the light can be deflected along the first deflection direction or the second deflection direction within the first plane after passing through each first beam deflection structure 1101. Therefore, after passing through multiple first beam deflection structures 1101, light with a maximum deflection angle along the first deflection direction or light with a maximum deflection angle along the second deflection direction can be obtained, and the maximum deflection angle is equal to the sum of the set angles of the multiple first beam deflection structures 1101.

[0093] For example, by setting the state of the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111 of multiple first beam deflection structures 1101, light located in the first plane and between the maximum deflection angle along the first deflection direction and the maximum deflection angle along the second deflection direction can be obtained. The deflection angle of the light can be calculated or obtained by combining the set deflection angles of multiple liquid crystal polarization gratings 112.

[0094] Therefore, the beam deflection device 100 can not only obtain light with the maximum deflection angle, but also obtain light with multiple different deflection angles, thereby achieving beam scanning and enabling the beam to be scanned in one dimension within the first plane. For example, the number of beam deflection structures 110 in the beam deflection device 100 can be 2, 3, or 4, etc., and this is not limited in the present embodiment.

[0095] In some examples, as shown in FIG1 , adjacent first beam deflecting structures 1101 in a first direction X can be bonded together using refractive index matching adhesive. For example, the thickness of the refractive index matching adhesive can range from 200 nm to 2 μm. The thickness of the refractive index matching adhesive is related to the viscosity and density of the refractive index matching adhesive, as well as the rotation speed of the glue roller, and is not limited here. Of course, the embodiments of the present disclosure do not limit the method for securing adjacent first beam deflecting structures 1101. For example, clamping and other methods can also be used.

[0096] In some examples, as shown in Figures 1 and 2, the periodic arrangement direction of the liquid crystal directors of the second liquid crystal layer 1120 of the liquid crystal polarization grating 112 in the first beam deflection structure 1101 is a second direction Y. The first direction X and the second direction Y form a first plane. For example, the first deflection direction can be a positive Y direction, where deflection toward the first deflection direction represents a positive deflection toward the Y direction; the second deflection direction can be a negative Y direction, where deflection toward the second deflection direction represents a negative deflection toward the Y direction. By setting the periodic arrangement direction of the liquid crystal directors of the liquid crystal polarization grating 112, the liquid crystal polarization grating 112 can adjust the polarization state of the incident light and change the deflection direction of the light by utilizing the periodic arrangement of the liquid crystal directors. It should be noted that Figure 2 only schematically illustrates one case of the second direction Y, and the periodic arrangement direction of the liquid crystal directors can be any direction perpendicular to the first direction X.

[0097] In some examples, as shown in Figure 1, the first polarization state may be a right circular polarization state, and the second polarization state may be a left circular polarization state. For example, the first polarization state may be a left circular polarization state, and the second polarization state may be a right circular polarization state.

[0098] For example, when the liquid crystal polarization grating 112 includes the second liquid crystal layer 1120 and the second liquid crystal layer 1120 only includes the third state S3, the liquid crystal polarization grating 112 may be referred to as a passive liquid crystal polarization grating.

[0099] FIG4 is a side view schematic diagram of another light beam deflection device provided in an embodiment of the present disclosure; FIG5 is a diagram illustrating the correspondence between the state of the first liquid crystal layer of the light beam deflection device shown in FIG4 and the deflection angle of the outgoing light. As shown in FIG4 , the light beam deflection device 100 includes two first light beam deflection structures 1101, the two first light beam deflection structures 1101 being a first-stage first light beam deflection structure 1101a and a second-stage first light beam deflection structure 1101b. The liquid crystal polarization grating 112 of the first-stage first light beam deflection structure 1101a is set to deflect at an angle of θ1, and the liquid crystal polarization grating 112 of the second-stage first light beam deflection structure 1101b is set to deflect at an angle of θ2. For example, the liquid crystal polarization gratings 112 of the two first light beam deflection structures 1101 can be passive liquid crystal polarization gratings.

[0100] For example, as shown in Figures 4 and 5, when the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111 of the first-stage first beam deflecting structure 1101a is in the second state S2 and the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111 of the second-stage first beam deflecting structure 1101b is in the first state S1, assuming that light incident on the beam deflecting device is in a first polarization state, the light in the first polarization state does not change its polarization state after passing through the liquid crystal variable wave plate 111 of the first-stage first beam deflecting structure 1101a. After passing through the liquid crystal polarization grating 112 of the first-stage first beam deflecting structure 1101a, the light is deflected by θ1 in the first plane in the first deflection direction and becomes light in the second polarization state. The light in the second polarization state returns to the first polarization state after passing through the liquid crystal variable wave plate 111 of the second-stage first beam deflecting structure 1101b. After further passing through the liquid crystal polarization grating 112 of the second-stage first beam deflecting structure 1101b, the light is deflected by θ2 in the first plane in the first deflection direction and becomes light in the second polarization state. Therefore, after passing through the beam deflecting device 100 , the light in the first polarization state is deflected in the first deflection direction within the first plane by an angle of θ1+θ2.

[0101] For example, as shown in Figures 4 and 5, when the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111 of the first-stage first beam deflecting structure 1101a is in the first state S1 and the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111 of the second-stage first beam deflecting structure 1101b is in the second state S2, light in a first polarization state changes to light in a second deflection state after passing through the liquid crystal variable wave plate 111 of the first-stage first beam deflecting structure 1101a. After passing through the liquid crystal polarization grating 112 of the first-stage first beam deflecting structure 1101a, the light is deflected by θ1 in the first plane toward the second deflection direction and changes to light in the first polarization state. The light in the first polarization state does not change its polarization state after passing through the liquid crystal variable wave plate 111 of the second-stage first beam deflecting structure 1101b. After continuing to pass through the liquid crystal polarization grating 112 of the second-stage first beam deflecting structure 1101b, the light is deflected by θ2 in the first plane toward the first deflection direction and changes to light in the second polarization state. Thus, after passing through the beam deflecting device 100, the light in the first polarization state is deflected in the first deflection direction within the first plane by an angle of -θ1+θ2. It should be noted that the negative sign preceding θ1 indicates that the deflection direction is the second deflection direction, and the positive sign preceding θ1 indicates that the deflection direction is the first deflection direction. If the result of -θ1+θ2 is a negative value, the light is deflected in the second deflection direction. If the result of -θ1+θ2 is a positive value, the light is deflected in the first deflection direction.

[0102] By analogy, the corresponding relationship shown in Figure 5 can be obtained, which will not be repeated here. After the light beam passes through the beam deflection device 100, the maximum angle it can be deflected is ±(θ1+θ2), and the field of view of the beam deflection device 100 is 2(θ1+θ2). A positive sign indicates that the deflection direction is a first deflection direction within the first plane, and a negative sign indicates that the deflection direction is a second deflection direction within the first plane. By separately setting the states of the two first liquid crystal layers 1110 of the beam deflection device 100, light with four different deflection angles can be obtained.

[0103] FIG6 is a side view schematic diagram of another light beam deflection device provided by an embodiment of the present disclosure; FIG7 is a diagram showing the corresponding relationship between the state of the first liquid crystal layer of the light beam deflection device shown in FIG6 and the deflection angle of the output light. As shown in FIG6 and FIG7 , the beam deflecting device 100 includes four first beam deflecting structures 1101, namely a first-stage first beam deflecting structure 1101a, a second-stage first beam deflecting structure 1101b, a third-stage first beam deflecting structure 1101c, and a fourth-stage first beam deflecting structure 1101d. The liquid crystal polarization grating 112 of the first-stage first beam deflecting structure 1101a is deflected at a set angle of θ1, the liquid crystal polarization grating 112 of the second-stage first beam deflecting structure 1101b is deflected at a set angle of θ2, the liquid crystal polarization grating 112 of the third-stage first beam deflecting structure 1101c is deflected at a set angle of θ3, and the liquid crystal polarization grating 112 of the fourth-stage first beam deflecting structure 1101d is deflected at a set angle of θ4. For example, the liquid crystal polarization gratings 112 of the four first beam deflecting structures 1101 may be passive liquid crystal polarization gratings.

[0104] For example, as shown in Figures 6 and 7, when the states of the first liquid crystal layer 1110 of the four first beam deflection structures 1101 are the second state S2, the first state S1, the first state S1 and the first state S1, respectively, assuming that the light incident on the beam deflection device 100 is in the first polarization state, the light in the first polarization state does not change its polarization state after passing through the liquid crystal variable wave plate 111 of the first-stage first beam deflection structure 1101a, and after passing through the liquid crystal polarization grating 112 of the first-stage first beam deflection structure 1101a, the light is deflected by θ1 in the first plane toward the first deflection direction and becomes light in the second polarization state. The light in the second polarization state changes into light in the first polarization state after passing through the liquid crystal variable wave plate 111 of the second-stage first beam deflecting structure 1101b. After passing through the liquid crystal polarization grating 112 of the second-stage first beam deflecting structure 1101b, the light in the second polarization state is deflected by θ2 toward the first deflection direction in the first plane and changes into light in the second polarization state. The light in the second polarization state changes into light in the first polarization state after passing through the liquid crystal variable wave plate 111 of the third-stage first beam deflecting structure 1101c. After passing through the liquid crystal polarization grating 112 of the third-stage first beam deflecting structure 1101c, the light in the first polarization state is deflected by θ3 toward the first deflection direction in the first plane and changes into light in the second polarization state. The light in the second polarization state changes into light in the first polarization state after passing through the liquid crystal variable wave plate 111 of the fourth-stage first beam deflecting structure 1101d. After passing through the liquid crystal polarization grating 112 of the fourth-stage first beam deflecting structure 1101d, the light in the second polarization state is deflected by θ4 toward the first deflection direction in the first plane and changes into light in the second polarization state. Therefore, after passing through the beam deflecting device 100 , the light in the first polarization state is deflected in the first deflection direction within the first plane by an angle of θ1+θ2+θ3+θ4.

[0105] By analogy, the corresponding relationship shown in Figure 7 can be obtained, which will not be repeated here. After the light beam passes through the beam deflecting device 100, the maximum angle that can be deflected is ±(θ1+θ2+θ3+θ4), and the field of view of the beam deflecting device 100 is 2(θ1+θ2+θ3+θ4). The positive sign indicates that the deflection direction is the first deflection direction within the first plane, and the negative sign indicates that the deflection direction is the second deflection direction within the first plane. By setting the states of the four first liquid crystal layers 1110 of the beam deflecting device 100 respectively, light with multiple different deflection angles as shown in Figure 7 can be obtained. It should be noted that the state of the first liquid crystal layer 1110 shown in Figure 7 is not unique, and the same deflection angle of the light emitted from the beam deflecting device 100 can correspond to different states, which is not limited here.

[0106] Figure 8 is a numerical diagram of the deflection angle of the outgoing light obtained by the light beam deflection device shown in Figure 6. As shown in Figure 8, by setting the state of the first liquid crystal layer 1110 of the liquid crystal variable wave plate 111, the polarization state of the light entering the liquid crystal polarization grating 112 can be set, and thus the deflection direction and angle of the light can be set. The deflection angles of the four liquid crystal polarization gratings 112 are ±θ1, ±θ2, ±θ3, and ±θ4, respectively. According to the permutation and combination calculation formula, by combining the possible situations of the four liquid crystal polarization gratings 112, 2*2*2*2=16 situations can be obtained. For example, in some of the 16 situations, the deflection angle of the light obtained may be the same.

[0107] In some examples, when the multiple set angles of the beam deflection device 100 using a passive liquid crystal polarization grating are all different, the beam deflection device 100 can obtain more deflection angles. As shown in Figure 5, when θ1 and θ2 are different, the beam deflection device 100 can obtain four different deflection angles. However, when θ1 and θ2 are the same, the beam deflection device 100 can only obtain two different deflection angles. As shown in Figure 8, when θ1, θ2, θ3, and θ4 are all different, the beam deflection device 100 can obtain up to 16 different deflection angles. When at least any two of the angles are the same, the beam deflection device 100 can obtain fewer angles than when all four set angles are different.

[0108] In some examples, the values ​​of the multiple setting angles of the beam deflection device 100 using a passive liquid crystal polarization grating can be in an arithmetic progression or a geometric progression. Of course, the embodiment of the present disclosure does not limit the relationship between the values ​​of the multiple setting angles.

[0109] For example, as shown in FIG8 , using four set angles, which can be θ, 2θ, 3θ, and 4θ, as an example, by substituting the four set angles into the formula in the figure for calculation, 11 different deflection angles can be obtained, namely ±10θ, ±8θ, ±6θ, ±4θ, ±2θ, and 0, and these 11 different deflection angles are evenly distributed. Thus, when multiple angles are in an arithmetic progression, not only can more deflection angles be obtained, but the obtained multiple deflection angles are also evenly distributed between the maximum deflection angles (±10θ) of two different deflection directions. For example, the beam deflection device 100 can be used in products that require a uniform distribution of deflection angles.

[0110] For example, as shown in Figure 8, taking the four set angles of θ, 2θ, 4θ, and 8θ as an example, by substituting the four set angles into the figure, 14 different deflection angles can be obtained, namely ±15θ, ±13θ, ±11θ, ±9θ, ±7θ, ±5θ, ±3θ, and ±θ. Therefore, when multiple angles are in a geometric progression, not only can more deflection angles be obtained, but the obtained multiple deflection angles are also evenly distributed between the maximum deflection angles (±10θ) of two different deflection directions.

[0111] Figure 9 is a schematic side view of another light beam deflection device according to an embodiment of the present disclosure. As shown in Figure 9, the liquid crystal polarization grating 112 further includes a second driver, and the second liquid crystal layer 1120 further includes a fourth state S4. The second driver is configured to drive the second liquid crystal layer 1120 to be in the third state S3 or the fourth state S4. In the fourth state S4, the liquid crystal polarization grating 112 is configured to maintain the polarization state and deflection angle of the light.

[0112] In this example, the second liquid crystal layer 1120 of the liquid crystal polarization grating 112 has two states, which can be adjusted by a second driver. Thus, when the beam deflection device 100 has the same number of first beam deflecting structures 1101, compared to when the second liquid crystal layer 1120 of the liquid crystal polarization grating 112 only has the third state S3, by adjusting the state of the second liquid crystal layer 1120 of the liquid crystal polarization grating 112, light passing through the same number of first beam deflecting structures 1101 can be combined to produce light with more different deflection directions and angles, thereby producing light with more different deflection directions and angles. Furthermore, because the second liquid crystal layer 1120 of the liquid crystal polarization grating 112 has the fourth state S4, the setting angles of the multiple liquid crystal polarization gratings 112 of the multiple first beam deflecting structures 1101 can have a wider range of values.

[0113] For example, when the liquid crystal polarization grating 112 includes a second liquid crystal layer 1120 and a second driver, and the second liquid crystal layer 1120 includes a third state S3 and a fourth state S4, the liquid crystal polarization grating 112 may be referred to as an active liquid crystal polarization grating 112b.

[0114] FIG10 illustrates the corresponding relationship between the states of the first and second liquid crystal layers of the light beam deflection device shown in FIG4 and the deflection angle of the emitted light. As shown in FIG4 and FIG10 , the light beam deflection device 100 includes two first beam deflection structures 1101. For example, the liquid crystal polarization gratings 112 of the two first beam deflection structures 1101 may be active liquid crystal polarization gratings.

[0115] For example, as shown in Figures 4 and 10, when the first liquid crystal layer 1110 of the first-stage first beam deflection structure 1101a is in the second state S2 and the second liquid crystal layer 1120 is in the first state S1, and the first liquid crystal layer 1110 of the second-stage first beam deflection structure 1101b is in the first state S1 and the second liquid crystal layer 1120 is in the first state S1, assuming that the light incident on the beam deflection device is in a first polarization state, the polarization state of the light of the first polarization state does not change after passing through the liquid crystal variable wave plate 111 of the first-stage first beam deflection structure 1101a, and after passing through the liquid crystal polarization grating 112 of the first-stage first beam deflection structure 1101a, the light is deflected by θ1 in the first plane toward the first deflection direction and becomes light of the second polarization state. After passing through the liquid crystal variable wave plate 111 of the second-stage first beam deflection structure 1101b, the light in the second polarization state is converted to the first polarization state. After passing through the liquid crystal polarization grating 112 of the second-stage first beam deflection structure 1101b, the light is deflected by θ2 in the first plane in the first deflection direction and converted to the second polarization state. Thus, after passing through the beam deflection device 100, the light in the first polarization state is deflected by an angle of θ1 + θ2 in the first plane in the first deflection direction.

[0116] For example, as shown in Figures 4 and 10, when the first liquid crystal layer 1110 of the first-stage first beam deflecting structure 1101a is in the second state S2 and the second liquid crystal layer 1120 is in the second state S2, and the first liquid crystal layer 1110 of the second-stage first beam deflecting structure 1101b is in the second state S2 and the second liquid crystal layer 1120 of the liquid crystal polarization grating 112 is in the first state S1, light with a first polarization state does not change its polarization state after passing through the liquid crystal variable wave plate 111 of the first-stage first beam deflecting structure 1101a, and does not change its polarization state or deflection angle after passing through the liquid crystal polarization grating 112 of the first-stage first beam deflecting structure 1101a. Light with a first polarization state does not change its polarization state after passing through the liquid crystal variable wave plate 111 of the second-stage first beam deflecting structure 1101b, but is deflected by θ2 in the first plane toward the first deflection direction after passing through the liquid crystal polarization grating 112 of the second-stage first beam deflecting structure 1101b and becomes light with a second polarization state. Therefore, after passing through the beam deflecting device 100 , the light in the first polarization state is deflected in the first deflection direction within the first plane by an angle of θ2.

[0117] By analogy, the corresponding relationship shown in Figure 10 can be obtained, which will not be repeated here. After the light beam passes through the light beam deflecting device 100, the maximum angle that can be deflected is ±(θ1+θ2), and the field of view of the light beam deflecting device 100 is 2(θ1+θ2). The positive sign indicates that the deflection direction is the first deflection direction within the first plane, and the negative sign indicates that the deflection direction is the second deflection direction within the first plane. By setting the states of the first liquid crystal layer 1110 and the second liquid crystal layer 1120 of the light beam deflecting device 100 respectively, light with multiple deflection angles as shown in Figure 10 can be obtained. It should be noted that the states of the first liquid crystal layer 1110 and the second liquid crystal layer 1120 shown in Figure 10 are not unique. The same deflection angle of the light emitted from the light beam deflecting device 100 can correspond to different states, which is not limited here.

[0118] For example, as shown in FIG4 , when the second liquid crystal layers 1120 of both active liquid crystal polarization gratings are in the third state S3, the light beam deflection device 100 using active liquid crystal polarization gratings is equivalent to the light beam deflection device 100 using passive liquid crystal polarization gratings. Furthermore, the light beam deflection device 100 using active liquid crystal polarization gratings 112b can also achieve the deflection angles shown in FIG10 . That is, the light beam deflection device 100 using active liquid crystal polarization gratings can achieve all the deflection angles shown in FIG5 and FIG10 . Therefore, the light beam deflection device 100 using active liquid crystal polarization gratings can achieve more deflection angles than the light beam deflection device 100 using passive liquid crystal polarization gratings.

[0119] For example, when the beam deflecting device 100 has two first beam deflecting structures 1101 , the beam deflecting device 100 using an active liquid crystal polarization grating can obtain up to five more deflection angles than the beam deflecting device 100 using a passive liquid crystal polarization grating.

[0120] FIG11 illustrates the corresponding relationship between the states of the first and second liquid crystal layers and the deflection angle of the emitted light in the light beam deflection device shown in FIG6 . As shown in FIG6 , the light beam deflection device 100 includes four first beam deflection structures 1101 . For example, the liquid crystal polarization gratings 112 of the four first beam deflection structures 1101 may be active liquid crystal polarization gratings 112 b.

[0121] For example, as shown in Figures 6 and 11, when the states of the first liquid crystal layer 1110 of the four first beam deflection structures 1101 are the second state S2, the first state S1, the first state S1 and the first state S1, and the states of the second liquid crystal layer 1120 are all the first state S1, assuming that the light incident on the beam deflection device is in the first polarization state, the polarization state of the light of the first polarization state does not change after passing through the liquid crystal variable wave plate 111 of the first-stage first beam deflection structure 1101a, and after passing through the liquid crystal polarization grating 112 of the first-stage first beam deflection structure 1101a, the light is deflected by θ1 in the first plane toward the first deflection direction and becomes light of the second polarization state. The light in the second polarization state changes into light in the first polarization state after passing through the liquid crystal variable wave plate 111 of the second-stage first beam deflection structure 1101b. After passing through the liquid crystal polarization grating 112 of the second-stage first beam deflection structure 1101b, the light in the second polarization state is deflected by θ2 toward the first deflection direction in the first plane and changes into light in the second polarization state. The light in the second polarization state changes into light in the first polarization state after passing through the liquid crystal variable wave plate 111 of the third-stage first beam deflection structure 1101c. After passing through the liquid crystal polarization grating 112 of the third-stage first beam deflection structure 1101c, the light in the first polarization state is deflected by θ3 toward the first deflection direction in the first plane and changes into light in the second polarization state. The light in the second polarization state changes into light in the first polarization state after passing through the liquid crystal variable wave plate 111 of the fourth-stage first beam deflection structure 1101d. After passing through the liquid crystal polarization grating 112 of the fourth-stage first beam deflection structure 1101d, the light in the second polarization state is deflected by θ4 toward the first deflection direction in the first plane and changes into light in the second polarization state. Therefore, after passing through the beam deflecting device 100 , the light in the first polarization state is deflected in the first deflection direction within the first plane by an angle of θ1+θ2+θ3+θ4.

[0122] By analogy, the corresponding relationship shown in Figure 11 can be obtained, which will not be repeated here. After the light beam passes through the beam deflection device 100, the maximum angle that can be deflected is ±(θ1+θ2+θ3+θ4). The field of view of the beam deflection device 100 is 2(θ1+θ2+θ3+θ4). The positive sign indicates that the deflection direction is the first deflection direction within the first plane, and the negative sign indicates that the deflection direction is the second deflection direction within the first plane. By setting the states of the four first liquid crystal layers 1110 and the four second liquid crystal layers 1120 of the beam deflection device 100 respectively, light with multiple different deflection angles as shown in the figure can be obtained. It should be noted that the states of the first liquid crystal layer 1110 and the second liquid crystal layer 1120 shown in the figure are not unique. The same deflection angle of the light emitted from the beam deflection device 100 can correspond to different states, which is not limited here.

[0123] In some examples, by setting the state of the second liquid crystal layer 1120 , the active liquid crystal polarization grating 112 b can be made not to change the polarization state and deflection angle of light, so that the beam deflection device 100 including the four first beam deflection structures 1101 can achieve multiple deflection angles.

[0124] For example, when the states of the four second liquid crystal layers 1120 of the beam deflection device 100 are all in the third state S3, the deflection angle of the output light that can be obtained by the beam deflection device 100 is equivalent to that of the beam deflection device 100 comprising four first beam deflection structures 1101, and the liquid crystal polarization gratings 112 of the four first beam deflection structures 1101 are all passive liquid crystal polarization gratings. For example, the beam deflection device 100 can obtain the deflection angle shown in Figure 8.

[0125] For example, when one of the four second liquid crystal layers 1120 of the beam deflection device 100 is in the fourth state S4, the deflection angle of the outgoing light that can be obtained by the beam deflection device 100 is equivalent to that of a beam deflection device 100 comprising three first beam deflection structures 1101, wherein the liquid crystal polarization gratings 112 of the three first beam deflection structures 1101 are all passive liquid crystal polarization gratings.

[0126] For example, when two of the four second liquid crystal layers 1120 of the beam deflection device 100 are in the fourth state S4, the deflection angle of the outgoing light that can be obtained by the beam deflection device 100 is equivalent to that of a beam deflection device 100 comprising two first beam deflection structures 1101, wherein the liquid crystal polarization gratings 112 of the two first beam deflection structures 1101 are both passive liquid crystal polarization gratings. For example, the deflection angle shown in Figure 5 can be obtained.

[0127] For example, when three of the four second liquid crystal layers 1120 of the beam deflection device 100 are in the fourth state S4, the deflection angle of the outgoing light that can be obtained by the beam deflection device 100 is equivalent to that of a beam deflection device 100 including a first beam deflection structure 1101, and the liquid crystal polarization grating 112 of the first beam deflection structure 1101 is a passive liquid crystal polarization grating.

[0128] For example, when four of the four second liquid crystal layers 1120 of the light beam deflecting device 100 are in the fourth state S4 , the light beam deflecting device 100 does not deflect light.

[0129] Thus, a beam deflection device 100 comprising four first beam deflection structures 1101, wherein the liquid crystal polarization gratings 112 of the four first beam deflection structures 1101 are active liquid crystal polarization gratings, can achieve the above five situations and obtain all the deflection angles obtained in the above five situations. FIG11 only illustrates the deflection angles of a portion of the emitted light and the corresponding states of the first liquid crystal layer 1110 and the second liquid crystal layer 1120, and does not illustrate all of them one by one.

[0130] In some examples, the multiple setting angles of the light beam deflection device 100 using an active liquid crystal polarization grating can be the same or different, and the embodiments of the present disclosure are not limited thereto. Because the light beam deflection device 100 using an active liquid crystal polarization grating can obtain a plurality of deflection angles by adjusting the states of the first liquid crystal layer 1110 and the second liquid crystal layer 1120, the light beam deflection device 100 using an active liquid crystal polarization grating has a lower requirement for the setting angles and can have a wider range of values.

[0131] For example, the multiple setting angles of the beam deflection device 100 using an active liquid crystal polarization grating can be in an arithmetic progression or a geometric progression, or at least two setting angles can be the same.

[0132] For example, as shown in FIG11 , taking the four set angles of θ, 2θ, 3θ, and 4θ as an example, by setting the first liquid crystal layer 1110 and the second liquid crystal layer 1120 to be in different states, the light beam deflection device 100 using the active liquid crystal polarization grating 112b can obtain 21 different deflection angles, namely ±10θ, ±9θ, ±8θ, ±7θ, ±6θ, ±5θ, ±4θ, ±3θ, ±2θ, θ, and 0.

[0133] For example, as shown in the figure, taking the four set angles of θ, 2θ, 4θ, and 8θ as an example, by setting the first liquid crystal layer 1110 and the second liquid crystal layer 1120 to be in different states, the light beam deflection device 100 using the active liquid crystal polarization grating 112b can obtain ±15θ, ±14θ, ±13θ, ±12θ, ±11θ, ±10θ, ±9θ, ±8θ, ±7θ, ±6θ, ±5θ, ±4θ, ±3θ, ±2θ, ±θ and 0, a total of 31 different deflection angles.

[0134] For example, as shown in the figure, taking the four set angles of θ, 2θ, 4θ, and 4θ as an example, by setting the first liquid crystal layer 1110 and the second liquid crystal layer 1120 to be in different states, the light beam deflection device 100 using the active liquid crystal polarization grating 112b can obtain ±11θ, ±10θ, ±9θ, ±8θ, ±7θ, ±6θ, ±5θ, ±4θ, ±3θ, ±2θ, ±1θ and 0, a total of 23 different deflection angles.

[0135] In some examples, as shown in Figures 1, 4 and 6, the setting angles of the liquid crystal polarization gratings 112 of the multiple first beam deflection structures 1101 are arranged in order from small to large along the direction from the first side E1 to the second side E2 of the beam deflection device 100, thereby reducing the impact of the liquid crystal polarization gratings 112 on the reduction of diffraction efficiency.

[0136] FIG12A is a schematic diagram of the structure of another beam deflection structure provided in an embodiment of the present disclosure. As shown in FIG12A , the beam deflection structure 110 includes a first beam deflection structure 1101 and a second beam deflection structure 1102. The first deflection direction and the second deflection direction of the liquid crystal polarization grating 112 in the second beam deflection structure 1102 are located in a second plane where the first direction X and the third direction Z are located. The third direction Z is perpendicular to both the first direction X and the second direction Y. The beam deflection device 100 includes at least one second beam deflection structure 1102. Multiple first beam deflection structures 1101 and at least one second beam deflection structure 1102 are arranged along the first direction X. The beam deflection device 100 can deflect light in the first plane through multiple first beam deflection structures 1101, and can also deflect light in the second plane through at least one second beam deflection structure 1102. Thus, the beam deflection device 100 can scan the light beam in two planes, achieving two-dimensional scanning of the light beam.

[0137] In some examples, as shown in FIG12A , the at least one second beam deflecting structure 1102 of the beam deflecting device 100 is located on a side of the plurality of first beam deflecting structures 1101 away from the first side E1. Of course, the present disclosure is not limited thereto, and the at least one second beam deflecting structure 1102 of the beam deflecting device 100 may also be located on a side of the plurality of first beam deflecting structures 1101 away from the second side E2.

[0138] In some examples, as shown in FIG. 12A , the periodic arrangement direction of the liquid crystal directors of the second liquid crystal layer 1120 in the second beam deflecting structure 1102 is the third direction Z.

[0139] In some examples, as shown in FIG12A , the beam deflection device 100 may include multiple second beam deflection structures 1102 , which are arranged along the first direction X. Multiple second beam deflection structures 1102 can achieve a greater angle of deflection, and by setting the state of the first liquid crystal layer 1110 or the second liquid crystal layer 1120 , multiple different deflection angles can be achieved. FIG12A schematically illustrates that the beam deflection structure 110 includes two first beam deflection structures 1101 and two second beam deflection structures 1102 , but the disclosed embodiments are not limited thereto.

[0140] In some examples, the angle deflection and polarization state change of the light beam by the second light beam deflecting structure 1102 of the light beam deflecting device 100 refer to the first light beam deflecting structure 1101 described above, and are not described again here.

[0141] Figure 12B is a schematic front view of a liquid crystal polarization grating in the second beam deflection structure shown in Figure 12A. As shown in Figures 12A and 12B, the periodic arrangement direction of the liquid crystal directors in the second liquid crystal layer 1120 of the liquid crystal polarization grating 112 in the second beam deflection structure 1102 is in a third direction Z. The first direction X and the third direction Z form a second plane. For example, the periodic arrangement direction of the liquid crystal directors in the second liquid crystal layer 1120 of the liquid crystal polarization grating 112 in the first beam deflection structure 1101 shown in Figure 12A is in a second direction Y. For details, please refer to Figure 2.

[0142] FIG13 is a schematic diagram of the structure of a liquid crystal variable wave plate provided in one embodiment of the present disclosure. As shown in FIG13 , the liquid crystal variable wave plate 111 includes a first substrate 1112, a second substrate 1117, a first orientation layer 1114, a second orientation layer 1115, a first transparent conductive layer 1113, a second transparent conductive layer 1116, and a first liquid crystal layer 1110. The second substrate 1117 is disposed opposite the first substrate 1112, with the first liquid crystal layer 1110 located between the first and second substrates 1112, 1117; the first orientation layer 1114 is located between the first liquid crystal layer 1110 and the first substrate 1112, and the second orientation layer 1115 is located between the first liquid crystal layer 1110 and the second substrate 1117; the first transparent conductive layer 1113 is located between the first orientation layer 1114 and the first substrate 1112, and the second transparent conductive layer 1116 is located between the second orientation layer 1115 and the second substrate 1117.

[0143] The first driver includes a first transparent conductive layer 1113 and a second transparent conductive layer 1116. When the voltage signal between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 is a first voltage V1, the first liquid crystal layer 1110 is in a first state S1. When the voltage signal between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 is a second voltage V2, the first liquid crystal layer 1110 is in a second state S2. Thus, by applying different voltage signals, the first liquid crystal layer 1110 can be switched between the first state S1 and the second state S2, thereby switching the liquid crystal variable wave plate 111 between a full-wave plate and a half-wave plate, thereby changing or maintaining the polarization state of a light beam.

[0144] In some examples, the liquid crystal molecules of the first liquid crystal layer 1110 are aligned, and the thickness of the first liquid crystal layer 1110 may be in the range of 2 um to 5 um.

[0145] In some examples, the first alignment layer 1114 and the second alignment layer 1115 can be formed using a rubbing alignment process or a photo-controlled alignment process. For example, polyimide (PI) is commonly used for rubbing alignment, while azobenzene (SD1), polyethylene 4-methoxycinnamate (PVMC), or photosensitive polyimide is commonly used for photo-controlled alignment. The thickness of the first alignment layer 1114 and the second alignment layer 1115 can range from 100 nm to 500 nm.

[0146] In some examples, the thickness of the first transparent conductive layer 1113 and the second transparent conductive layer 1116 may be in the range of 500 nm to 2 μm. For example, the material of the first transparent conductive layer 1113 and the second transparent conductive layer 1116 may be indium tin oxide (ITO).

[0147] In some examples, the first substrate 1112 and the second substrate 1117 may be high-transmittance glass. For example, the high-transmittance glass may have a transmittance greater than or equal to 95% for light with a wavelength in the range of 850 nm to 1550 nm. This can increase the transmittance of light incident on the liquid crystal variable wave plate 111. For example, the thickness of the first substrate 1112 and the second substrate 1117 may range from 100 μm to 700 μm.

[0148] In some examples, as shown in FIG13 , the liquid crystal variable wave plate 111 may further include a first anti-reflection (AR) film 1118 and a second AR film 1119. The first AR film 1118 is located on a side of the first substrate 1112 away from the first transparent conductive layer 1113, and the second AR film 1119 is located on a side of the second substrate 1117 away from the second transparent conductive layer 1116. The first AR film 1118 and the second AR film 1119 can increase the reflection and transmittance of light beams, thereby increasing the transmittance of light incident on the liquid crystal variable wave plate 111. For example, the thickness of the first AR film 1118 and the second AR film 1119 can range from 200 nm to 1 μm.

[0149] In some examples, as shown in FIG13 , the liquid crystal variable wave plate 111 may further include a plurality of spacers PS, which are located between the first substrate 1112 and the second substrate 1117 to support the first substrate 1112 and the second substrate 1117 and seal the first liquid crystal layer 1110. For example, the spacers PS may be small polystyrene balls mixed with a sealant, and the diameter of the spacers PS is consistent with the thickness of the liquid crystal cell, thereby providing support and uniformizing the cell thickness.

[0150] Figure 14 is a schematic diagram of a liquid crystal variable wave plate according to an embodiment of the present disclosure, with a first voltage applied. Figures 15 and 16 are simulated diagrams of a light beam in the state shown in Figure 14. As shown in Figure 14, when the first liquid crystal layer 1110 utilizes nematic liquid crystal, the liquid crystal variable wave plate 111 is referred to as a nematic liquid crystal variable wave plate. The thickness of the first liquid crystal layer 1110 of the nematic liquid crystal variable wave plate is d = λ / 2Δn, where λ is the wavelength of the incident light and Δn is the refractive index difference of the liquid crystal.

[0151] For example, as shown in FIG14 , when the first voltage V1 applied between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 of the nematic liquid crystal variable wave plate is 0 V, the liquid crystal of the first liquid crystal layer 1110 does not deflect, and the first liquid crystal layer 1110 is in the first state S1. At this time, the nematic liquid crystal variable wave plate is a half-wave plate.

[0152] For example, as shown in FIG15 , when the incident light incident on the nematic liquid crystal variable wave plate is left-handed circularly polarized light, the light emitted from the nematic liquid crystal variable wave plate is right-handed circularly polarized light. As shown in FIG16 , when the incident light incident on the nematic liquid crystal variable wave plate is right-handed circularly polarized light, the light emitted from the nematic liquid crystal variable wave plate is left-handed circularly polarized light. Ex in FIG15 and FIG16 represents the electric field in the X direction, and Ez represents the electric field in the Z direction. The light propagates in the Y direction. During the propagation in the Y direction, the light has electric fields along the X and Z directions, and the light is circularly polarized light. Ex and Ez in the light beam simulation diagram in the present disclosure are the same as those in FIG15 and FIG16 and will not be repeated here.

[0153] Figure 17 is a schematic diagram of the liquid crystal variable wave plate shown in Figure 14 with a second voltage applied; Figures 18 and 19 are simulated diagrams of the light beam in the state shown in Figure 17. As shown in Figure 17, when the second voltage V2 applied between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 of the nematic liquid crystal variable wave plate is a saturation voltage, the liquid crystal molecules in the first liquid crystal layer 1110 are rearranged under the action of the electric field, with the long axis of the liquid crystals oriented in the direction of the electric field. The first liquid crystal layer 1110 is in the second state S2. At this point, the nematic liquid crystal variable wave plate 111 functions as a full-wave plate, and the deflection state of light does not change.

[0154] For example, as shown in Figure 18, when the incident light entering the nematic liquid crystal variable wave plate is left-handed circularly polarized light, the light exiting the nematic liquid crystal variable wave plate is still left-handed circularly polarized light. As shown in Figure 19, when the incident light entering the nematic liquid crystal variable wave plate is right-handed circularly polarized light, the light exiting the nematic liquid crystal variable wave plate is still right-handed circularly polarized light.

[0155] Figure 20 is a diagram illustrating the state of the first liquid crystal layer of another liquid crystal variable wave plate provided by an embodiment of the present disclosure after a first voltage is applied; Figure 21 is a diagram illustrating the state of the first liquid crystal layer of the liquid crystal variable wave plate shown in Figure 20 after a second voltage is applied. As shown in Figures 20 and 21, when the first liquid crystal layer 1110 uses ferroelectric liquid crystal, the liquid crystal variable wave plate 111 is called a ferroelectric liquid crystal variable wave plate. Ferroelectric liquid crystal molecules are in a helical state when no voltage is applied. When a voltage is applied, they untwist and become nematic liquid crystal. When negative and positive voltages are applied to the ferroelectric liquid crystal molecules, the long axis of the liquid crystal deflects in different directions, with a deflection angle of approximately 45 degrees. Ferroelectric liquid crystals are characterized by electro-induced untwisting, which offers the advantage of fast response speed.

[0156] For example, as shown in FIG19 , FIG19 (a) is a side view schematic diagram of the first liquid crystal layer 1110, and FIG19 (b) is a top view schematic diagram of the first liquid crystal side. When a first voltage V1 applied to the ferroelectric liquid crystal variable wave plate is a positive voltage, the liquid crystal in the first liquid crystal layer 1110 unwinds in one direction under the action of the electric field, and the first liquid crystal layer 1110 is in a first state S1. At this time, the ferroelectric liquid crystal variable wave plate is a half-wave plate. For example, when the incident light entering the ferroelectric liquid crystal variable wave plate is left-handed circularly polarized light, the outgoing light is right-handed circularly polarized light; when the incident light entering the ferroelectric liquid crystal variable wave plate is right-handed circularly polarized light, the outgoing light is left-handed circularly polarized light.

[0157] For example, as shown in FIG21 , FIG21 (a) is a side view schematic diagram of the first liquid crystal layer 1110, and FIG21 (b) is a top view schematic diagram of the first liquid crystal side. When the second voltage V2 applied between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 of the ferroelectric liquid crystal variable wave plate 111 is a negative voltage, the liquid crystal in the first liquid crystal layer 1110 unwinds in the other direction under the action of the electric field, and the first liquid crystal layer 1110 is in the second state S2. At this time, the ferroelectric liquid crystal variable wave plate is a full-wave plate, and the deflection state of light does not change. For example, when the incident light entering the ferroelectric liquid crystal variable wave plate is left-handed circularly polarized light, the outgoing light remains left-handed circularly polarized light; when the incident light entering the ferroelectric liquid crystal variable wave plate is right-handed circularly polarized light, the outgoing light remains right-handed circularly polarized light.

[0158] Figure 22 is a schematic diagram of another liquid crystal variable wave plate according to an embodiment of the present disclosure, with a first voltage applied; Figure 23 is a schematic diagram of the liquid crystal variable wave plate shown in Figure 22, with a second voltage applied. As shown in Figures 22 and 23, the liquid crystal variable wave plate 111 includes a first substrate 1112, a second substrate 1117, a first alignment layer 1114, a second alignment layer 1115, a first transparent conductive layer 1113, a second transparent conductive layer 1116, a first liquid crystal layer 1110, a first quarter-wave plate 112a, and a second quarter-wave plate 112b. The second substrate 1117 is arranged opposite to the first substrate 1112, and the first liquid crystal layer 1110 is located between the first substrate 1112 and the second substrate 1117; the first alignment layer 1114 is located between the first liquid crystal layer 1110 and the first substrate 1112, and the second alignment layer 1115 is located between the first liquid crystal layer 1110 and the second substrate 1117; the first transparent conductive layer 1113 is located between the first alignment layer 1114 and the first substrate 1112, and the second transparent conductive layer 1116 is located between the second alignment layer 1115 and the second substrate 1117; the first quarter-wave plate 112a is located on the side of the first substrate 1112 close to the first side E1, and the second quarter-wave plate 112b is located on the side of the second substrate 1117 away from the first side E1.

[0159] The first driver includes a first transparent conductive layer 1113 and a second transparent conductive layer 1116. When the voltage signal between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 is a first voltage V1, the first liquid crystal layer 1110 is in a first state S1. When the voltage signal between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 is a second voltage V2, the first liquid crystal layer 1110 is in a second state S2. Thus, by applying a voltage signal, the first liquid crystal layer 1110 can be switched between the first state S1 and the second state S2, thereby switching the liquid crystal variable wave plate 111 between a full-wave plate and a half-wave plate, thereby changing or maintaining the polarization state of a light beam.

[0160] For example, when the first liquid crystal layer 1110 uses twisted nematic (TN) liquid crystal, the liquid crystal variable wave plate 111 is called a twisted nematic liquid crystal variable wave plate 111 .

[0161] For example, as shown in FIG22 , when a first voltage V1 applied between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 of the twisted nematic liquid crystal variable wave plate is 0V, the liquid crystal in the first liquid crystal layer 1110 does not deflect, and the first liquid crystal layer 1110 is in a first state S1. After linearly polarized light passes through the twisted nematic liquid crystal, its polarization direction is deflected by 90 degrees. For example, left-handed circularly polarized light passes through the first quarter-wave plate 112a and becomes linearly polarized light with a polarization direction of EH. After linearly polarized light EH passes through the twisted nematic liquid crystal, its polarization direction is deflected by 90 degrees to EV. Linearly polarized light EV passes through the second quarter-wave plate 112b and becomes right-handed circularly polarized light. Thus, left-handed circularly polarized light passes through the twisted nematic liquid crystal variable wave plate 111 and becomes right-handed circularly polarized light, and vice versa. This is not further described here.

[0162] For example, as shown in FIG23 , when a first voltage V1 applied between the first transparent conductive layer 1113 and the second transparent conductive layer 1116 of the twisted nematic liquid crystal variable wave plate is a saturation voltage, the liquid crystals in the first liquid crystal layer 1110 rearrange themselves under the action of the electric field, with the long axis of the liquid crystals oriented in the direction of the electric field. The first liquid crystal layer 1110 is in a second state S2, and the polarization direction of linearly polarized light remains unchanged after passing through the twisted nematic liquid crystals. For example, left-handed circularly polarized light passes through the first quarter-wave plate 112a and becomes linearly polarized light with a polarization direction of EH. After the linearly polarized light EH passes through the twisted nematic liquid crystals, its polarization direction remains unchanged. The linearly polarized light EH passes through the second quarter-wave plate 112b and becomes left-handed circularly polarized light. Consequently, the left-handed circularly polarized light remains left-handed circularly polarized light after passing through the twisted nematic liquid crystal variable wave plate, and vice versa. This will not be further described here.

[0163] Figure 24 is a side view schematic diagram of a liquid crystal polarization grating provided in one embodiment of the present disclosure; Figure 25 is a top view schematic diagram of the second liquid crystal layer of the liquid crystal polarization grating shown in Figure 24. As shown in Figures 24 and 25, the liquid crystal polarization grating 112 includes a third substrate 1122, a fourth substrate 1127, a third alignment layer 1124, a fourth alignment layer 1125, and a second liquid crystal layer 1120. The fourth substrate 1127 is disposed opposite the third substrate 1122, the second liquid crystal layer 1120 is located between the third and fourth substrates 1122, the third alignment layer 1124 is located between the second and third substrates 1122, and the fourth alignment layer 1125 is located between the second and fourth substrates 1120, 1127. This liquid crystal polarization grating 112 can also be referred to as a passive liquid crystal polarization grating 112a. This passive liquid crystal polarization grating 112a can change the polarization state and deflection angle of incident light.

[0164] In some examples, the passive liquid crystal polarization grating 112a can be made of liquid crystal polymer, which is subjected to a spin coating process, with multiple layers of spin coating controlling the thickness of the liquid crystal cell, and finally cured by ultraviolet light.

[0165] In some examples, the liquid crystal director of the second liquid crystal layer 1120 of the passive liquid crystal polarization grating 112 a changes periodically, and the thickness of the second liquid crystal layer 1120 may be in the range of 2 μm to 5 μm.

[0166] In some examples, the third substrate 1122 may be an encapsulation layer, typically made of silicon dioxide, carbon tetrachloride, polymethyl methacrylate (PMMA), etc. For example, the fourth substrate 1127 may be high-transmittance glass. For example, the thickness of the third substrate 1122 may range from 100 μm to 700 μm.

[0167] In some examples, due to the periodic deflection of the liquid crystal orientation of the passive liquid crystal polarization grating 112a, the third alignment layer 1124 and the fourth alignment layer 1125 are often aligned using a photo-controlled process. Materials used for photo-controlled alignment include azobenzene (SD1), polyethylene 4-methoxycinnamate (PVMC), and photosensitive polyimide. For example, the thickness of the third alignment layer 1124 and the fourth alignment layer 1125 can range from 100 nm to 500 nm.

[0168] In some examples, as shown in FIG24 , the passive liquid crystal polarization grating 112a may further include a third anti-reflection (AR) film 1128 and a fourth AR film 1129. The third AR film 1128 is located on a side of the third substrate 1122 away from the second liquid crystal layer 1120, and the fourth AR film 1129 is located on a side of the fourth substrate 1127 away from the second liquid crystal layer 1120. The third AR film 1128 and the fourth AR film 1129 may increase the reflection and transmission of light beams, thereby increasing the transmittance of light incident on the liquid crystal variable wave plate 111. For example, the thickness of the third AR film 1128 and the fourth AR film 1129 may range from 200 nm to 1 μm.

[0169] In some examples, as shown in FIG. 24 , the passive liquid crystal polarization grating 112 a may further include a plurality of isolation columns PS, which are located between the third substrate 1122 and the fourth substrate 1127 to support the third substrate 1122 and the fourth substrate 1127 and seal the second liquid crystal layer 1120 .

[0170] Figure 26 is a schematic diagram of another liquid crystal polarization grating according to an embodiment of the present disclosure, wherein a third voltage is applied to the liquid crystal polarization grating; and Figure 27 is a schematic diagram of the liquid crystal polarization grating shown in Figure 26, wherein a fourth voltage is applied to the liquid crystal polarization grating. As shown in Figures 26 and 27, the liquid crystal polarization grating 112 includes a third substrate 1122, a fourth substrate 1127, a third alignment layer 1124, a fourth alignment layer 1125, a third transparent conductive layer 1123, a fourth transparent conductive layer 1126, and a second liquid crystal layer 1120. The fourth substrate 1127 is arranged opposite to the third substrate 1122, and the second liquid crystal layer 1120 is located between the third substrate 1122 and the fourth substrate 1127; the third orientation layer 1124 is located between the second liquid crystal layer 1120 and the third substrate 1122, the fourth orientation layer 1125 is located between the second liquid crystal layer 1120 and the fourth substrate 1127, the third transparent conductive layer 1123 is located between the third orientation layer 1124 and the third substrate 1122, and the fourth transparent conductive layer 1126 is located between the fourth orientation layer 1125 and the fourth substrate 1127. The second driver includes the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126.

[0171] As shown in Figure 26, when the voltage signal between the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126 is a third voltage V3, the second liquid crystal layer 1120 is in a third state S3. The third state S3 of the second liquid crystal layer 1120 shown in Figure 26 is consistent with the third state S3 shown in Figures 24 and 26. As shown in Figure 27, when the voltage signal between the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126 is a fourth voltage V4, the second liquid crystal layer 1120 is in a fourth state S4. This liquid crystal polarization grating 112 may also be referred to as an active liquid crystal polarization grating 112b. By applying different voltage signals, the third state S3 and the fourth state S4 of the second liquid crystal layer 1120 can be changed, thereby changing the polarization state and deflection angle of the incident light or not changing the polarization state and deflection angle of the incident light.

[0172] For example, as shown in FIG26 , when the third voltage V3 applied between the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126 of the active liquid crystal polarization grating 112 b is 0 V, the liquid crystal in the second liquid crystal layer 1120 does not deflect, the liquid crystal director of the second liquid crystal layer changes periodically, and the second liquid crystal layer 1120 is in a third state S3. At this time, the active liquid crystal polarization grating 112 b deflects the incident light, and the set angle θ of the deflection is related to the period Λ of the liquid crystal polarization grating 112 (see FIG25 ). The smaller the grating period Λ, the larger the set angle θ of the deflection. The set angle θ of the deflection and the period Λ of the liquid crystal polarization grating 112 satisfy the formula:

[0173] For example, as shown in FIG27 , when the fourth voltage V4 applied between the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126 of the active liquid crystal polarization grating 112 b is a saturation voltage, the liquid crystal molecules of the second liquid crystal layer 1120 are rearranged under the action of the electric field, and the long axis of the liquid crystal turns toward the direction of the electric field. The second liquid crystal layer 1120 is in the fourth state S4. At this time, the active liquid crystal polarization grating 112 b has no deflection effect on the incident light.

[0174] In some examples, in the third state S3 , the liquid crystal director of the second liquid crystal layer 1120 changes periodically, and the thickness of the second liquid crystal layer 1120 may be in the range of 2 um to 5 um.

[0175] In some examples, the third alignment layer 1124 and the fourth alignment layer 1125 may be formed using a rubbing alignment process or a photo-controlled alignment process. For example, the thickness of the third alignment layer 1124 and the fourth alignment layer 1125 may be in the range of 100 nm to 500 nm.

[0176] In some examples, the thickness of the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126 may be in the range of 500 nm to 2 μm. For example, the material of the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126 may be indium tin oxide (ITO).

[0177] In some examples, the third substrate 1122 and the fourth substrate 1127 may be made of high-transmittance glass. For example, the thickness of the third substrate 1122 and the fourth substrate 1127 may range from 100 μm to 700 μm.

[0178] In some examples, as shown in Figures 26 and 27, the active liquid crystal polarization grating 112b may further include a third anti-reflection and anti-reflection film 1128 and a fourth anti-reflection and anti-reflection film 1129. The third anti-reflection and anti-reflection film 1128 is located on a side of the third substrate 1122 away from the second liquid crystal layer 1120, and the fourth anti-reflection and anti-reflection film 1129 is located on a side of the fourth substrate 1127 away from the second liquid crystal layer 1120. The third anti-reflection and anti-reflection film 1128 and the fourth anti-reflection and anti-reflection film 1129 can increase the reflection and transmission of the light beam, thereby increasing the transmittance of the light incident on the liquid crystal variable wave plate 111. For example, the thickness of the third anti-reflection and anti-reflection film 1128 and the fourth anti-reflection and anti-reflection film 1129 can range from 200 nm to 1 μm.

[0179] In some examples, as shown in Figures 26 and 27, the active liquid crystal polarization grating 112b can also include a plurality of isolation columns PS, which are located between the third substrate 1122 and the fourth substrate 1127 to support the third substrate 1122 and the fourth substrate 1127 and seal the second liquid crystal layer 1120.

[0180] Figures 28 to 35 are simulated diagrams of light beams with different grating periods under the state shown in Figure 26. As shown in Figures 28 to 35, taking 940nm incident light as an example, when no voltage is applied to either side of the active liquid crystal polarization grating 112b, that is, when the third voltage V3 is 0V, left-handed circularly polarized light is incident vertically from above, and right-handed circularly polarized light is emitted obliquely from the lower left; when right-handed circularly polarized light is incident vertically from above, left-handed circularly polarized light is emitted obliquely from the lower right.

[0181] For example, when the grating period is 1.9 um, according to the formula in the previous article, the set angle θ of the deflection of the liquid crystal polarization grating 112 is 30 degrees. As shown in FIG28 , left-handed circularly polarized light is incident vertically from above, and right-handed circularly polarized light is emitted at an angle from the lower left. As shown in FIG29 , right-handed circularly polarized light is incident vertically from above, and left-handed circularly polarized light is emitted at an angle from the lower right.

[0182] For example, when the grating period is 2.8um, the set angle θ of the deflection of the liquid crystal polarization grating 112 is 20 degrees; as shown in Figure 30, left-handed circularly polarized light is incident vertically from above, and right-handed circularly polarized light is emitted obliquely from the lower left; as shown in Figure 31, right-handed circularly polarized light is incident vertically from above, and left-handed circularly polarized light is emitted obliquely from the lower right.

[0183] For example, when the grating period is 5.4 um, the set angle θ of the deflection of the liquid crystal polarization grating 112 is 10 degrees; as shown in FIG32 , left-handed circularly polarized light is incident vertically from above, and right-handed circularly polarized light is emitted obliquely from the lower left; as shown in FIG33 , right-handed circularly polarized light is incident vertically from above, and left-handed circularly polarized light is emitted obliquely from the lower right.

[0184] For example, when the grating period is 10.8um, the set angle θ of the deflection of the liquid crystal polarization grating 112 is 5 degrees; as shown in Figure 34, left-handed circularly polarized light is incident vertically from above, and right-handed circularly polarized light is emitted obliquely from the lower left; as shown in Figure 35, right-handed circularly polarized light is incident vertically from above, and left-handed circularly polarized light is emitted obliquely from the lower right.

[0185] FIG36 is a schematic diagram of a beam deflection structure provided by an embodiment of the present disclosure. As shown in FIG36 , the beam deflection structure 110 includes a passive liquid crystal polarization grating 112a and a liquid crystal variable wave plate 111. The liquid crystal variable wave plate 111 can be a nematic liquid crystal variable wave plate, a ferroelectric liquid crystal variable wave plate, or a twisted nematic liquid crystal variable wave plate.

[0186] As shown in FIG36 , the liquid crystal variable wave plate 111 of the beam deflection structure 110 includes a first substrate 1112, a second substrate 1117, a first alignment layer 1114, a second alignment layer 1115, a first transparent conductive layer 1113, a second transparent conductive layer 1116, and a first liquid crystal layer 1110. The passive liquid crystal polarization grating 112a of the beam deflection structure 110 includes a second substrate 1117, a fourth substrate 1127, a third alignment layer 1124, a fourth alignment layer 1125, and a second liquid crystal layer 1120, which are shared with the liquid crystal variable wave plate 111. For example, the first substrate 1112, the second substrate 1117, and the fourth substrate 1127 may be made of high-transmittance glass.

[0187] In some examples, as shown in Figure 36, the beam deflection structure 110 can also include a first anti-reflection and anti-reflection film 1118 close to the first side E1 and a fourth anti-reflection and anti-reflection film 1129 close to the second side E2, and a plurality of isolation columns PS arranged between the first substrate 1112 and the second substrate 1117, and between the second substrate 1117 and the fourth substrate 1127.

[0188] Figures 37 and 38 are schematic diagrams of the beam deflection structure shown in Figure 36. As shown in Figure 37, when a first voltage V1 is applied to the liquid crystal variable wave plate 111 (e.g., the voltage state is "0"), the first liquid crystal layer 1110 is in the first state S1, and the liquid crystal variable wave plate 111 converts the right-handed circular polarization of the incident light into left-handed circular polarization. The left-handed circularly polarized light then becomes right-handed circularly polarized light after passing through the passive liquid crystal polarization grating 112a. The light beam is then deflected downward and leftward by a set angle θ, the value of which depends on the period Λ of the liquid crystal polarization grating 112.

[0189] As shown in FIG38 , when a second voltage V2 is applied to the liquid crystal variable wave plate 111, for example, the voltage state is recorded as “1”, the first liquid crystal layer 1110 is in the second state S2, the liquid crystal variable wave plate 111 does not change the polarization state of the incident light, and the right-handed circularly polarized light is deflected to the lower right by a set angle θ after passing through the passive liquid crystal polarization grating 112a. The size of the set angle θ depends on the period Λ of the liquid crystal polarization grating 112.

[0190] FIG39 is a schematic diagram of another beam deflection structure provided by an embodiment of the present disclosure. As shown in FIG39 , the beam deflection structure 110 includes an active liquid crystal polarization grating 112b and a liquid crystal variable wave plate 111. The liquid crystal variable wave plate 111 can be a nematic liquid crystal variable wave plate, a ferroelectric liquid crystal variable wave plate, or a twisted nematic liquid crystal variable wave plate.

[0191] As shown in FIG39 , the liquid crystal variable wave plate 111 of the beam deflection structure 110 includes a first substrate 1112, a second substrate 1117, a first alignment layer 1114, a second alignment layer 1115, a first transparent conductive layer 1113, a second transparent conductive layer 1116, and a first liquid crystal layer 1110. The active liquid crystal polarization grating 112b of the beam deflection structure 110 includes a second substrate 1117, a fourth substrate 1127, a third alignment layer 1124, a fourth alignment layer 1125, a third transparent conductive layer 1123, a fourth transparent conductive layer 1126, and a second liquid crystal layer 1120, which are shared with the liquid crystal variable wave plate 111. For example, the first substrate 1112, the second substrate 1117, and the fourth substrate 1127 may be made of high-transmittance glass.

[0192] In some examples, as shown in Figure 39, the beam deflection structure 110 also includes a first anti-reflection and anti-reflection film 1118 close to the first side E1 and a fourth anti-reflection and anti-reflection film 1129 close to the second side E2, and a plurality of isolation columns PS arranged between the first substrate 1112 and the second substrate 1117, and between the second substrate 1117 and the fourth substrate 1127.

[0193] Figures 40 to 42 are schematic diagrams of the beam deflection structure shown in Figure 39. As shown in Figure 40, when a first voltage V1 is applied to the liquid crystal variable wave plate 111 (e.g., the voltage state is recorded as "0"), the first liquid crystal layer 1110 is in the first state S1, and the liquid crystal variable wave plate 111 converts the right-handed circular polarization of the incident light into left-handed circular polarization. When a fourth voltage V4 is applied to the active liquid crystal polarization grating 112b (e.g., the voltage state is recorded as "1"), the second liquid crystal layer 1120 is in the fourth state S4, and the left-handed circularly polarized light remains unchanged after passing through the active liquid crystal polarization grating 112b, and the beam is not deflected.

[0194] As shown in Figure 41, when a first voltage V1 is applied to the liquid crystal variable wave plate 111, for example, the voltage state is recorded as "0", the first liquid crystal layer 1110 is in the first state S1, and the liquid crystal variable wave plate 111 converts the right-handed circular polarization of the incident light into left-handed circular polarization; when a third voltage V3 is applied to the active liquid crystal polarization grating 112b, for example, the voltage state is recorded as "0", the second liquid crystal layer 1120 is in the third state S3, and the left-handed circular polarized light is converted into right-handed circular polarized light after passing through the active liquid crystal polarization grating 112b, and the light beam is deflected to the lower left by a set angle θ, and the size of the set angle θ depends on the period Λ of the liquid crystal polarization grating 112.

[0195] As shown in Figure 42, when a second voltage V2 is applied to the liquid crystal variable wave plate 111, for example, the voltage state is recorded as "1", the first liquid crystal layer 1110 is in the second state S2, and the liquid crystal variable wave plate 111 has no effect on the polarization state of the incident light; when a third voltage V3 is applied to the active liquid crystal polarization grating 112b, for example, the voltage state is recorded as "0", the second liquid crystal layer 1120 is in the third state S3, and the right-handed circularly polarized light becomes left-handed circularly polarized light after passing through the active liquid crystal polarization grating 112b, and the light beam is deflected to the lower right by a set angle θ, and the size of the set angle θ depends on the period Λ of the liquid crystal polarization grating 112.

[0196] FIG43 is a graph showing the voltage state of the first liquid crystal layer of the beam deflection device shown in FIG4 and the corresponding deflection angle of the output light. As shown in FIG4 and FIG43 , the beam deflection device 100 includes two beam deflection structures 110, which are arranged along a first side E1 and in a direction pointing toward a second side E2. The liquid crystal polarization gratings 112 of the two beam deflection structures 110 can both be passive liquid crystal polarization gratings 112a. For example, the passive liquid crystal polarization grating 112a of the beam deflection structure 110 near the first side E1 can have a set deflection angle θ of 10 degrees, while the passive liquid crystal polarization grating 112a of the beam deflection structure 110 near the second side E2 can have a set deflection angle θ of 20 degrees. Taking a nematic liquid crystal variable wave plate 111 as an example, by applying the voltages shown in FIG43 to the two liquid crystal variable wave plates 111 of the beam deflection device 100, the beam deflection device 100 can achieve the deflection angles shown in FIG43 . Thus, the beam deflecting device 100 can achieve beam deflection between -30 degrees and 30 degrees. In the figure, the number "1" represents the saturation voltage, which is the second voltage V2 mentioned above, and the number "0" represents the shutdown voltage, which is the first voltage V1 mentioned above.

[0197] FIG44 is a graph showing the voltage state of the liquid crystal layer and the deflection angle of the emitted light of the beam deflection device shown in FIG4. As shown in FIG4 and FIG44, the beam deflection device 100 includes two beam deflection structures 110, which are arranged in a direction from the first side E1 to the second side E2. The liquid crystal polarization gratings 112 of the two beam deflecting structures 110 are both active liquid crystal polarization gratings 112b. For example, the active liquid crystal polarization grating 112b of the beam deflecting structure 110 near the first side E1 has a set deflection angle θ of 10 degrees, while the active liquid crystal polarization grating 112b of the beam deflecting structure 110 near the second side E2 has a set deflection angle θ of 20 degrees. Taking a nematic liquid crystal variable wave plate 111 as an example, by applying the voltages shown in FIG44 to the two liquid crystal variable wave plates 111 and the two active liquid crystal polarization gratings 112b of the beam deflecting device 100, the beam deflecting device 100 can achieve the deflection angles shown in FIG44. Thus, the beam deflecting device 100 can achieve a beam deflection between -30 degrees and 30 degrees.

[0198] FIG45 is a graph showing the voltage state of the first liquid crystal layer of the light beam deflection device shown in FIG6 and the corresponding deflection angle of the outgoing light. As shown in FIG6 and FIG45 , the light beam deflection device 100 includes four light beam deflection structures 110, which are arranged along a direction from the first side E1 to the second side E2. The liquid crystal polarization gratings 112 of the four light beam deflection structures 110 are all passive liquid crystal polarization gratings 112a. For example, the four passive liquid crystal polarization gratings 112a arranged along the direction from the first side E1 to the second side E2 have set deflection angles θ of 5 degrees, 10 degrees, 15 degrees, and 20 degrees, respectively. Taking a nematic liquid crystal variable wave plate 111 as an example, by applying the voltages shown in FIG45 to the four liquid crystal variable wave plates 111 of the light beam deflection device 100, the light beam deflection device 100 can achieve the deflection angles shown in FIG45 . Consequently, the light beam deflection device 100 can achieve a light beam deflection between -50 degrees and 50 degrees.

[0199] FIG46 is a graph showing the voltage state of the liquid crystal layer of the light beam deflection device shown in FIG6 and the corresponding deflection angle of the outgoing light. As shown in FIG6 and FIG46 , the light beam deflection device 100 includes four light beam deflection structures 110, which are arranged in a direction from a first side E1 to a second side E2. The liquid crystal polarization gratings 112 of the four light beam deflection structures 110 are all active liquid crystal polarization gratings 112b. For example, the four active liquid crystal polarization gratings 112b arranged in a direction from the first side E1 to the second side E2 have set deflection angles θ of 5 degrees, 10 degrees, 20 degrees, and 20 degrees, respectively. Taking a nematic liquid crystal variable wave plate 111 as an example, by applying the voltages shown in FIG46 to the four liquid crystal variable wave plates 111 and the four active liquid crystal polarization gratings 112b of the light beam deflection device 100, the light beam deflection device 100 can achieve the deflection angles shown in FIG46 . Therefore, the beam deflecting device 100 can achieve beam deflection between -55 degrees and 55 degrees.

[0200] In some examples, the four beam deflection structures 110 in the beam deflection device 100 shown in FIG6 can all be first beam deflection structures 1101, and the two beam deflection structures 110 in the beam deflection device 100 shown in FIG4 can both be second beam deflection structures 1102. The four first beam deflection structures 1101 in FIG6 and the two second beam deflection structures 1102 in FIG4 are arranged in a direction from the first side E1 to the second side E2 to form a beam deflection device. Thus, the beam deflection device can achieve deflection of the light beam in two planes, thereby achieving two-dimensional scanning of the light beam. For example, the beam deflection device 100 composed of FIG6 and FIG4 can achieve deflection between -55 degrees and 55 degrees in the first plane, and simultaneously achieve deflection between -30 degrees and 30 degrees in the second plane. Of course, the embodiments of the present disclosure are not limited to this, and beam deflection structures 110 of other numbers and set angles can also be arranged in a direction from the incident light to the second side E2, thereby achieving other scanning angles.

[0201] FIG47 is a schematic diagram of another beam deflection device provided in an embodiment of the present disclosure. As shown in FIG47 , the beam deflection device 100 further includes a controller 120. The controller 120 is communicatively coupled to each of the first drivers 1111 of the first beam deflection structures 1101 and is configured to provide voltage signals to the first drivers 1111 to place the first liquid crystal layer 1110 in the first state S1 or the second state S2. For example, the controller 120 may be communicatively coupled to the first transparent conductive layer 1113 and the second transparent conductive layer 1116 of the first beam deflection structures 1101 to provide voltage signals thereto.

[0202] In some examples, as shown in FIG47 , the controller 120 of the beam deflecting device 100 can also be communicatively connected to each of the plurality of second drivers 1121 of the plurality of first beam deflecting structures 1101, and configured to provide voltage signals to the second drivers 1121 to place the second liquid crystal layer 1120 in the third state S3 or the fourth state S4. For example, the controller 120 can be communicatively connected to the third transparent conductive layer 1123 and the fourth transparent conductive layer 1126 of the plurality of first beam deflecting structures 1101 to provide voltage signals thereto.

[0203] In some examples, the controller 120 of the beam deflecting device 100 may also be communicatively connected to multiple drivers of multiple second beam deflecting structures 1102 , which will not be described in detail here.

[0204] It should be noted that FIG47 schematically shows a first driver 1111 and a second driver 1121 of a first beam deflecting structure 1101, which is only used to illustrate the communication connection relationship between the controller and the driver, and is not a limitation to the beam deflecting device 100.

[0205] FIG48 is a flow chart of a process for preparing a liquid crystal variable wave plate according to an embodiment of the present disclosure. As shown in FIG48 , (1) the glass is first cleaned with deionized water and then dried. (2) indium tin oxide (ITO) is then deposited by magnetron sputtering to prepare a transparent electrode. (3) A polyimide (PI) layer is then spin-coated. (4) The glass is dried. (5) The glass is oriented by rubbing with a flannel cloth. (6) The structure prepared above is aligned with a high-transmittance glass coated with indium tin oxide (ITO) so that the indium tin oxide (ITO) faces each other. A sealant mixed with polystyrene beads is used to determine the thickness of the liquid crystal cell. (7) The liquid crystal cell is finally vacuum-filled and then packaged. The liquid crystal cell is then manufactured. This liquid crystal cell can be used for the liquid crystal variable wave plate 111 of the present disclosure.

[0206] FIG49 is a flow chart of a process for preparing a passive liquid crystal polarization grating provided in one embodiment of the present disclosure. As shown in FIG49 , (1) the glass is first cleaned with deionized water and then dried. (2) an azobenzene photo-alignment material is then coated. (3) Drying is performed. (4) After patterned orientation is achieved using polarized light, (5) liquid crystal and polymer intermediates are applied by multiple spin coatings. (6) After reaching the desired thickness, the polymer is cured using ultraviolet light. (7) Finally, an encapsulation layer is applied to isolate water and oxygen, and the liquid crystal box is prepared. This liquid crystal box can be used for the passive liquid crystal polarization grating 112a of the present disclosure.

[0207] Figure 50 is a flow chart of the preparation process for an active liquid crystal polarization grating provided by one embodiment of the present disclosure. As shown in Figure 50, the glass is first cleaned with deionized water and then dried. Then, indium tin oxide (ITO) is deposited by magnetron sputtering to prepare a transparent electrode. An azobenzene photo-alignment material is then applied, dried, and patterned orientation is achieved using polarized light. The structure prepared above is aligned with high-transmittance glass coated with indium tin oxide (ITO), with the indium tin oxide (ITO) facing each other. A sealant mixed with polystyrene beads is used to determine the thickness of the liquid crystal box. Finally, vacuum filling and packaging are performed to complete the liquid crystal box. This liquid crystal box can be used for the active liquid crystal polarization grating 112b of the present disclosure.

[0208] An embodiment of the present disclosure also provides a laser radar. Figure 51 is a schematic structural diagram of a laser emission system of a laser radar provided by an embodiment of the present disclosure. As shown in Figure 51, the laser radar includes a laser emission system 210, which includes multiple lasers 211 and any of the above-mentioned beam deflection devices 100. The multiple lasers 211 are arranged corresponding to the beam deflection devices 100. The multiple lasers 211 are located on the first side E1 of the beam deflection device 100 and are configured to emit light beams toward the beam deflection device 100. Thus, the laser radar has the same beneficial effects as the beam deflection device 100. The beam deflection device 100 can deflect the light beam emitted by the laser 211 to achieve a large field of view. It can also achieve beam scanning by changing the state of the liquid crystal layer in the beam deflection device 100. Therefore, the number of lasers 211 can be reduced, reducing the size and cost of the laser emission system 210. The fan-shaped area in the figure represents the light beam emitted from the laser emission system 210.

[0209] For example, when the beam deflection device 100 includes multiple first beam deflection structures 1101, the laser radar can achieve one-dimensional beam scanning. For example, when the beam deflection device 100 includes multiple first beam deflection structures 1101 and at least one second beam deflection structure 1102, the laser radar can achieve two-dimensional scanning.

[0210] In some examples, as shown in Figure 51, the laser emission system 210 also includes a first driver chip 212, the first driver chip 212 includes a laser driver chip and a beam deflection device driver chip, the laser driver chip is configured to drive the laser 211 to emit a light beam, and the beam deflection device driver chip is configured to drive the beam deflection device to deflect the light beam emitted by the laser 211.

[0211] In some examples, when the first deflection state is a right-handed circular polarization state and the second polarization state is a left-handed circular polarization state, the laser 211 can emit linearly polarized light and unpolarized light. For example, when the light emitted by the laser 211 is linearly polarized light, a quarter-wave plate can be added to the light output side of the laser 211 to convert the linearly polarized light into circularly polarized light. For example, when the light emitted by the laser 211 is unpolarized light, a polarizer and a quarter-wave plate can be added to the light output side of the laser 211. The polarizer can convert the unpolarized light into linearly polarized light, and the quarter-wave plate can convert the linearly polarized light into circularly polarized light.

[0212] Figure 52 is a schematic diagram of the structure of a laser receiving system provided in accordance with an embodiment of the present disclosure. As shown in Figure 52 , the laser radar further includes a laser receiving system 220, which includes multiple detectors 221 configured to receive light beams. These detectors 221 can receive light beams reflected from a target, thereby obtaining relevant information about the target. The fan-shaped area in the figure represents the reflected light beams received by the laser receiving system 220.

[0213] In some examples, as shown in FIG. 52 , the laser receiving system 220 further includes a second driver chip 222 , which includes a detector driver chip configured to drive the detector 221 to receive the light beam reflected from the target.

[0214] In some examples, the laser receiving system 220 further includes a holographic lens, which can converge the light beam reflected from the target and can converge the reflected light in all directions into a centrally incident light beam. The detector 221 receives the converged light beam.

[0215] FIG53 is a schematic diagram of the structure of another laser receiving system provided by an embodiment of the present disclosure. As shown in FIG53 , the laser receiving system 220 includes multiple detectors 221 and a beam deflection device 100. The beam deflection device 100 is arranged corresponding to the multiple detectors 221. The multiple detectors 221 are located on the first side E1 of the beam deflection device 100. The multiple detectors 221 are configured to receive light beams from the beam deflection device 100. After the light beam reflected from the target passes through the beam deflection device 100, it can converge the radiated light in various directions into a centrally incident light beam, and the detector 221 receives the converged light beam. Thus, the beam deflection device 100 can replace the holographic lens, reduce the number of detectors 221, and reduce the size and cost of the laser receiving system 220.

[0216] In some examples, as shown in Figure 53, the laser receiving system 220 also includes a second driver chip 222, which includes a detector driver chip and a beam deflection device driver chip. The detector driver chip is configured to drive the detector 221 to receive the light beam, and the beam deflection device driver chip is configured to drive the beam deflection device 100 to deflect the light beam reflected back from the target to converge the light beam.

[0217] Figure 54 is a flowchart of a laser radar system according to an embodiment of the present disclosure. As shown in Figure 54 , the laser driver chip 2120 of the laser emission system 210 drives the laser 211 to emit a beam toward the beam deflection device 100. The beam deflection device driver chip 2121 then drives the beam deflection device 100 to deflect the beam emitted by the laser 211 toward the target.

[0218] The holographic lens 223 of the laser receiving system 220 converges the light beam reflected from the target into a centrally incident light beam, and the detector driving chip 2220 drives the detector 221. The detector 221 receives the converged centrally incident light beam. For example, relevant information about the target can be obtained through the time of flight (ToF) method.

[0219] In some examples, the laser radar may be a FLASH laser radar. The laser 211 may be a vertical-cavity surface-emitting laser (VCSEL). The detector 221 may be a photodetector (PIN-PD). Of course, the embodiments of the present disclosure are not limited to this.

[0220] For example, the lidar can be used in fields such as autonomous driving, intelligent robots, automatic logistics, or urban mapping.

[0221] There are a few points to note:

[0222] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to conventional designs.

[0223] (2) Unless there is any conflict, the features of the same embodiment and different embodiments of the present disclosure may be combined with each other.

[0224] The above are only specific embodiments of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A beam deflecting device having a first side and a second side opposite to each other in a first direction, comprising a beam deflecting structure, wherein the beam deflecting structure comprises: A liquid crystal variable wave plate, comprising a first liquid crystal layer and a first driver, wherein the first liquid crystal layer comprises a first state and a second state, wherein the first driver is configured to drive the first liquid crystal layer to be in the first state or the second state, wherein in the first state, the liquid crystal variable wave plate is configured to change light in a first polarization state into light in a second polarization state or change light in the second polarization state into light in the first polarization state, and in the second state, the liquid crystal variable wave plate is configured not to change the polarization state of light; as well as a liquid crystal polarization grating, arranged on a side of the liquid crystal variable wave plate away from the first side, comprising a second liquid crystal layer, wherein the second liquid crystal layer comprises a third state, wherein in the third state, the liquid crystal polarization grating is configured to change the light of the first polarization state into the light of the second polarization state and deflect the light by a set angle toward a first deflection direction, or to change the light of the second polarization state into the light of the first polarization state and deflect the light by the set angle toward a second deflection direction, wherein the first deflection direction and the second deflection direction are symmetrical with respect to a propagation direction of the light, The beam deflection structure comprises a first beam deflection structure, the first deflection direction and the second deflection direction of the liquid crystal polarization grating in the first beam deflection structure are located in a first plane where the first direction and the second direction are located, and the second direction is perpendicular to the first direction; The beam deflecting device includes a plurality of the first beam deflecting structures, and the plurality of the first beam deflecting structures are arranged along the first direction.

2. The beam deflection device according to claim 1, wherein: The periodic arrangement direction of the liquid crystal directors of the second liquid crystal layer of the liquid crystal polarization grating in the first beam deflecting structure is the second direction.

3. The beam deflection device according to claim 1, wherein: The first deflection state is a right-handed circular polarization state, and the second polarization state is a left-handed circular polarization state.

4. The beam deflection device according to claim 1, wherein: The liquid crystal polarization grating also includes a second driver, and the second liquid crystal layer also includes a fourth state. The second driver is configured to drive the second liquid crystal layer so that the second liquid crystal layer is in the third state or the fourth state. In the fourth state, the liquid crystal polarization grating is configured not to change the polarization state of light and the deflection angle of light.

5. The beam deflecting device according to claim 1, wherein: The values ​​of the multiple setting angles of the multiple first beam deflecting structures are different.

6. The beam deflection state according to claim 5, wherein: The values ​​of the multiple set angles are in an arithmetic progression or a geometric progression.

7. The beam deflecting device according to claim 5, wherein: The multiple first beam deflecting structures include four first beam deflecting structures, and four setting angles of the four first beam deflecting structures are 5 degrees, 10 degrees, 15 degrees and 20 degrees respectively.

8. The beam deflecting device according to claim 4, wherein: The plurality of first beam deflection structures include four first beam deflection structures, and setting angles of the liquid crystal polarization gratings of the four first beam deflection structures are 5 degrees, 10 degrees, 20 degrees and 20 degrees respectively.

9. The beam deflection device according to any one of claims 1 to 8, wherein: The beam deflection structure further includes a second beam deflection structure, wherein the first deflection direction and the second deflection direction of the liquid crystal polarization grating in the second beam deflection structure are located in a second plane where the first direction and the third direction are located, and the third direction is perpendicular to both the first direction and the second direction; The beam deflecting device includes at least one second beam deflecting structure, and the plurality of first beam deflecting structures and the at least one second beam deflecting structure are arranged along the first direction.

10. The beam deflecting device according to claim 9, wherein: The at least one second beam deflecting structure is located on a side of the plurality of first beam deflecting structures away from the first side or away from the second side.

11. The beam deflecting device according to claim 9, wherein: The periodic arrangement direction of the liquid crystal directors of the second liquid crystal layer in the second light beam deflecting structure is the third direction.

12. The beam deflecting device according to claim 8, wherein: The beam deflecting device includes a plurality of second beam deflecting structures, and the plurality of second beam deflecting structures are arranged along the first direction.

13. The beam deflecting device according to claim 12, wherein: The beam deflection device includes four first beam deflection structures and two second beam deflection structures, the setting angles of the liquid crystal polarization gratings of the four first beam deflection structures are 5 degrees, 10 degrees, 20 degrees and 20 degrees respectively, and the setting angles of the two second beam deflection structures are 10 degrees and 20 degrees respectively.

14. The beam deflecting device according to claim 1, wherein: The liquid crystal variable wave plate also includes: a first substrate; A second substrate is disposed opposite to the first substrate, and the first liquid crystal layer is located on the first substrate and between the second substrate; a first alignment layer, located between the first liquid crystal layer and the first substrate; a second alignment layer, located between the first liquid crystal layer and the second substrate; a first transparent conductive layer, located between the first alignment layer and the first substrate; and a second transparent conductive layer, located between the second alignment layer and the second substrate, Among them, the first driver includes the first transparent conductive layer and the second transparent conductive layer, when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a first voltage, the first liquid crystal layer is in the first state, and when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a second voltage, the first liquid crystal layer is in the second state.

15. The beam deflecting device according to claim 14, wherein: The first liquid crystal layer includes nematic liquid crystal or ferroelectric liquid crystal.

16. The beam deflecting device according to claim 14, wherein: The liquid crystal variable wave plate also includes: a first anti-reflection and anti-reflection film, located on a side of the first substrate away from the first transparent conductive layer; and The second anti-reflection and anti-reflection film is located on a side of the second substrate away from the second transparent conductive layer.

17. The beam deflecting device according to claim 1, wherein: The liquid crystal variable wave plate also includes: a first substrate; a second substrate, disposed opposite to the first substrate, wherein the first liquid crystal layer is located between the first substrate and the second substrate; a first alignment layer, located between the first liquid crystal layer and the first substrate; a second alignment layer, located between the first liquid crystal layer and the second substrate; A first transparent conductive layer, located between the first alignment layer and the first substrate; a second transparent conductive layer, located between the second alignment layer and the second substrate; a first quarter wave plate, located on a side of the first substrate close to the first side; and a second quarter wave plate, located on a side of the second substrate away from the first side, Among them, the first driver includes the first transparent conductive layer and the second transparent conductive layer, when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a first voltage, the first liquid crystal layer is in the first state, and when the voltage signal between the first transparent conductive layer and the second transparent conductive layer is a second voltage, the first liquid crystal layer is in the second state.

18. The beam deflecting device according to claim 17, wherein: The first liquid crystal layer includes twisted phase liquid crystal.

19. The beam deflecting device according to claim 14, wherein: The liquid crystal polarization grating comprises: a third substrate; a fourth substrate, arranged opposite to the third substrate, wherein the second liquid crystal layer is located between the third substrate and the fourth substrate; a third alignment layer, located between the second liquid crystal layer and the third substrate; and The fourth alignment layer is located between the second liquid crystal layer and the fourth substrate.

20. The beam deflecting device according to claim 19, wherein: The second substrate is located on a side of the first substrate away from the first side, the fourth substrate is located on a side of the third substrate away from the first side, and the second substrate and the third substrate are the same substrate.

21. The beam deflecting device according to claim 4, wherein: The liquid crystal polarization grating comprises: a third substrate; a fourth substrate, arranged opposite to the third substrate, wherein the second liquid crystal layer is located between the third substrate and the fourth substrate; a third alignment layer, located between the second liquid crystal layer and the third substrate; a fourth alignment layer, located between the second liquid crystal layer and the fourth substrate; a third transparent conductive layer, located between the third alignment layer and the third substrate; and a fourth transparent conductive layer, located between the fourth orientation layer and the fourth substrate, Wherein, the second driver includes the third transparent conductive layer and the fourth transparent conductive layer, when the voltage signal between the third transparent conductive layer and the fourth transparent conductive layer is the third voltage, the second liquid crystal layer is in the third state, and when the voltage signal between the third transparent conductive layer and the fourth transparent conductive layer is the fourth voltage, the second liquid crystal layer is in the fourth state.

22. The light beam deflecting device according to any one of claims 1 to 8, further comprising: The controller is communicatively connected to the plurality of first drivers of the plurality of first beam deflecting structures, and is configured to provide a voltage signal to the first drivers to put the first liquid crystal layer in a first state or a second state.

23. A laser radar, comprising a laser emission system, wherein: The laser emission system comprises a plurality of lasers and a beam deflection device according to any one of claims 1 to 22, wherein the plurality of lasers are arranged corresponding to the beam deflection device. The plurality of lasers are located on a first side of the beam deflecting device and are configured to emit beams toward the beam deflecting device.

24. The laser radar according to claim 23 further includes a laser receiving system, including a plurality of detectors, wherein the plurality of detectors are configured to receive the light beam.

25. The laser radar according to claim 24, wherein: The laser receiving system also includes the beam deflecting device, which is arranged corresponding to the multiple detectors. The multiple detectors are located on a first side of the beam deflecting device, and the multiple detectors are configured to receive light beams from the beam deflecting device.

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