CN220709345U - Laser radar based on liquid crystal geometric phase - Google Patents

Abstract

The utility model discloses a laser radar based on a liquid crystal geometric phase. In the technical scheme of the utility model, the laser reflection and reflection light collimation focusing module comprises a light-transmitting carrier, a liquid crystal selective reflection device for changing the laser emergent direction is arranged on the first side of the light-transmitting carrier, a liquid crystal diffraction lens for collimation and focusing of reflected light is arranged on the second side of the light-transmitting carrier, and the reflection, collimation and focusing of laser are completed through the liquid crystal selective reflection device and the liquid crystal diffraction lens.

Description

Laser radar based on liquid crystal geometric phase

Technical Field

The utility model relates to the field of laser radars, in particular to a laser radar based on liquid crystal geometric phase.

Background

Lidar has been widely used in the fields of autopilot, land mapping, robotics, and the like. There are different types of lidar, wherein the optical module is an important component of the lidar.

At present, in the related art, when the laser radar reflects and focuses laser light, the prism and the refraction lens in the optical device are used for completing, and for the laser radar with high performance, the corresponding size of the required prism and the refraction lens is increased.

Accordingly, the prior art is still in need of improvement and development.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present utility model aims to provide a laser radar based on liquid crystal geometric phase, so as to solve the problems of the prior art that the laser radar is large in size and weight, light and high in production cost.

The utility model provides a laser radar based on liquid crystal geometric phase, which comprises: the device comprises a laser emission module, an optical signal receiving module, a laser reflection and reflected light collimation focusing module and a phase adjusting module for changing the emergent direction of reflected light;

the laser reflection and reflection light collimation focusing module comprises a light-transmitting carrier, wherein the light-transmitting carrier comprises a first side and a second side opposite to the first side, the first side is provided with a liquid crystal selective reflection device for changing the laser emergent direction, and the second side is provided with a liquid crystal diffraction lens for collimation focusing of reflection light;

the laser emission module is arranged on the side surface of the laser reflection and reflection light collimation focusing module according to a preset angle;

the laser emitted by the laser emitting module irradiates onto the liquid crystal selective reflecting device, the liquid crystal selective reflecting device reflects the laser emitted by the laser emitting module to form first reflected light, the first reflected light irradiates to a target object through the phase adjusting module, the target object reflects the first reflected light to form second reflected light, and the second reflected light is collimated and focused to the optical signal receiving module through the phase adjusting module and the liquid crystal diffraction lens.

The utility model is further provided that the liquid crystal selective reflective device comprises: and the spiral axis of the cholesteric liquid crystal is vertically encapsulated on the first side of the light-transmitting carrier.

The utility model further provides that the light-transmitting carrier is a glass substrate or a silicon substrate.

The utility model further provides that the light receiving signal module is an avalanche photodetector, and the second reflected light is collimated and focused to the avalanche photodetector after passing through the liquid crystal diffraction lens.

The utility model further provides that the laser emitting module comprises an edge emitting laser.

The utility model further provides that the phase adjustment module comprises: the liquid crystal display device comprises a plurality of strip electrodes arranged at intervals and a strip electrode power supply circuit for outputting power supply voltage to the strip electrodes, wherein the strip electrode power supply circuit is connected with the strip electrodes, and liquid crystal molecules or semiconductors are packaged between the strip electrodes.

The utility model further provides that the strip electrode is a metal strip electrode, a nonmetal strip electrode or a semiconductor strip electrode.

The utility model further provides that the thickness of the strip-shaped electrode along the Z-axis direction is 50nm-150nm, and the gap between the adjacent strip-shaped electrodes is 100nm-300nm.

The utility model further provides that the strip electrode power supply circuit comprises: the external capacitor is used for outputting power supply voltage to the strip-shaped electrode;

the kernel is connected with the pre-storage register through the protocol conversion module;

the pre-storage register is connected with the signal register;

the switch is respectively connected with the potentiometer, the strip-shaped electrode and the signal register;

the external capacitor is connected with the switch through the potentiometer.

The utility model further provides that the strip electrode is arranged in the middle of the strip electrode power supply circuit.

The utility model provides a laser radar based on a liquid crystal geometric phase, a laser emitting module emits laser to a laser reflection and reflection light collimation focusing module, wherein the laser reflection and reflection light collimation focusing module comprises a light-transmitting carrier, a liquid crystal selective reflecting device for changing the emergent direction of the laser is arranged on a first side of the light-transmitting carrier, a liquid crystal diffraction lens for collimating and focusing the reflected light is arranged on a second side of the light-transmitting carrier, and the reflection, collimation and focusing of the laser are completed through the liquid crystal selective reflecting device and the liquid crystal diffraction lens.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained from the structures shown in these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a lidar based on liquid crystal geometric phase in the present utility model.

Fig. 2 is a structural view of a liquid crystal selective reflection device in the present utility model.

Fig. 3 is a structural diagram of a liquid crystal diffraction lens in the present utility model.

Fig. 4 is a diagram showing a simulation of the laser deflection effect of the phase adjustment module according to the present utility model.

Fig. 5 is a phase control effect simulation diagram of the phase control module in the present utility model.

Fig. 6 is a block diagram of a phase adjustment module in the present utility model.

FIG. 7 is a schematic diagram of the structure of the stripe electrodes and the liquid crystal molecules in the present utility model.

Fig. 8 is a graph showing the relationship between the gap between the stripe electrodes and the exit phase in the present utility model.

Fig. 9 is a graph showing the relationship between the phase angle and the emission phase of the liquid crystal molecules in the present utility model.

FIG. 10 is a diagram showing a connection structure between a power supply circuit for a strip electrode and the strip electrode according to the present utility model.

The marks in the drawings are as follows: 1. a laser emitting module; 2. an optical signal receiving module; 3. the laser reflection and reflected light collimation focusing module; 31. a first side; 311. a liquid crystal selective reflection device; 32. a second side; 321. a liquid crystal diffraction lens; 33. a light-transmitting carrier; 4. a phase adjustment module; 41. a strip electrode power supply circuit; 411. a kernel; 412. a protocol conversion module; 413. a pre-storage register; 414. a signal register; 415. a switch; 416. a potentiometer; 417. an external capacitor; 42. a strip electrode; 421. liquid crystal molecules; 422. a gap; 5. a target object.

Detailed Description

For a clearer understanding of technical features, objects and effects of the present utility model, a detailed description of embodiments of the present utility model will be made with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "rear", "upper", "lower", "left", "right", "longitudinal", "transverse", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", etc. are configured and operated in specific directions based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model, and do not indicate that the apparatus or element to be referred to must have specific directions, and thus should not be construed as limiting the present utility model. Among the existing lidars, lidars are classified into different types of lidars, for example, time of Flight (ToF) lidars, solid-state lidars, and the like, according to the operation principle. Wherein, in Time of Flight (ToF) lidar, after alignment of the matrix of pulsed laser diodes (Pulse Laser Diode, PLD) and the matrix of avalanche photodetectors (Avalanche Photodetector, APD) by the optical system, as the emitters and detectors of Time of Flight (ToF) lidar, in operation, the light rotates along the vertical axis of the lidar, detecting objects along the line of sight at all azimuth angles; in the Time of Flight (ToF) lidar, the resolution of the lidar is determined by the number, density, etc. of the emitters and detectors, and when it is required to align a plurality of emitters and detectors for high accuracy (for an optimal detection distance), a large spatial span (for a large vertical Field angle (FoV)), the difficulty of hardware integration is great, and thus, solid-state lidar has become a trend.

The prior art solid state lidar is mainly based on microelectromechanical systems (Micro Electro Mechanical System, MEMS) and single photon avalanche detectors (Single Photon Avalanche Diode, SPAD), both methods being based on silicon-based semiconductor fabrication. In the existing laser radar, when the laser is reflected and focused, the laser is completed based on a prism and a refractive lens in an optical device, in addition, when the laser is reflected, collimated and focused based on the prism and the refractive lens in the optical device, a mechanical structure is needed to be matched with the optical device, and therefore the size and the weight of the laser radar are increased, the laser radar is not light enough, and meanwhile, the problem of high production cost exists.

Based on the above, the utility model provides a laser radar based on liquid crystal geometric phase. As shown in fig. 1-3, the liquid crystal geometric phase-based laser radar may include a laser emitting module 1, an optical signal receiving module 2, a laser reflection and reflection light collimation focusing module 3, and a phase adjusting module 4; the laser emission module 1 is arranged on the side surface of the laser reflection and reflection light collimation focusing module 3 according to a preset angle, the laser emission module 1 is used for emitting laser to irradiate the laser reflection and reflection light collimation focusing module 3, wherein the preset angle refers to the angle at which the laser emitted by the laser emission module 1 can irradiate the laser reflection and reflection light collimation focusing module 3 and the laser reflection and reflection light collimation focusing module 3 can reflect the laser emitted by the laser emission module 1; the laser reflection and reflection light collimation focusing module 3 may include a light-transmitting carrier 33, where the light-transmitting carrier 33 includes a first side 31 and a second side 32 opposite to the first side 31, the first side 31 is provided with a liquid crystal selective reflection device 311 for changing the outgoing direction of the laser light, the second side 32 is provided with a liquid crystal diffraction lens 321 for collimation focusing of the reflected light, the liquid crystal selective reflection device 311 reflects the laser light emitted by the laser emitting module 1 to form a first reflected light, the first reflected light irradiates the target object 5 through the phase adjusting module 4, and the target object 5 reflects the first reflected light to form a second reflected light; the phase adjusting module 4 is used for changing the emergent direction of the first reflected light and the incident direction of the second reflected light; the optical signal receiving module 2 is configured to receive the reflected light collimated and focused by the liquid crystal diffraction lens 321.

In a specific application, the laser emitted by the laser emitting module 1 irradiates onto the liquid crystal selective reflecting device 311, the liquid crystal selective reflecting device 311 reflects the laser emitted by the laser emitting module 1 to form a first reflected light, the first reflected light irradiates to the target 5 through the phase adjusting module 4, the target 5 reflects the first reflected light to form a second reflected light, and the second reflected light is collimated and focused to the optical signal receiving module 2 through the phase adjusting module 4 and the liquid crystal diffraction lens 321. In this embodiment, the liquid crystal selective reflection device 311 and the liquid crystal diffraction lens 321 are used for completing the reflection, collimation and focusing of the laser, and the liquid crystal selective reflection device 311 and the liquid crystal diffraction lens 321 have the characteristics of high working efficiency, low manufacturing cost and easy integration, so that the liquid crystal selective reflection device 311 and the liquid crystal diffraction lens 321 replace the mode of reflecting, collimation and focusing of the laser by matching a prism, a refraction lens and a mechanical structure in the prior art, the volume and the weight of the laser radar are reduced, the laser radar is light and handy, and the production cost is reduced.

In addition, the resolution can reach the diffraction limit due to the characteristics of the liquid crystal diffraction lens 321, so the application of the liquid crystal diffraction lens 321 lays a foundation for multi-line scanning.

In the present embodiment, the laser emitting module 1 may include, but is not limited to, an edge emitting laser. In particular, the edge-emitting laser may be a laser emitting at a wavelength of 905 nm.

In some embodiments, as shown in FIG. 2, the liquid crystal selective reflective device 311 may comprise cholesteric liquid crystal having a helical axis vertically encapsulated in the first side 31 of the light transmissive carrier 33.

In some embodiments, the transparent carrier 33 may be a glass substrate, but of course, may be a carrier capable of transmitting light made of other materials, for example, the transparent carrier 33 may also be a silicon substrate.

Specifically, the glass substrate may be a cubic substrate, where a surface perpendicular to the thickness direction on the glass substrate may be a first side 31, and cholesteric liquid crystal is encapsulated on the surface of the first side 31, and reflection of laser emitted by the laser emitting module 1 by the cholesteric liquid crystal is completed to form first emission light; the other surface perpendicular to the thickness direction may be a second side 32, and a liquid crystal diffraction lens 321 is mounted on the surface of the second side 32, and collimation and focusing of second reflected light formed by reflecting the first reflected light by the target object 5 are performed by the liquid crystal diffraction lens 321. In this embodiment, the cholesteric liquid crystal reflecting mode and the liquid crystal diffraction lens 321 perform collimation and focusing of the second reflected light formed by the reflection of the target object 5, so that the laser radar has smaller volume and weight, is lighter, and has reduced production cost.

In order to further describe the lcd selective reflection device 311, in this embodiment, a simulation test is performed on the lcd selective reflection device 311 by using a FDTD module of simulation software lumical, and specific simulation details are as follows: the liquid crystal selective reflection device 311 includes cholesteric liquid crystal, and the light-transmitting carrier 33 is a glass substrate, and the cholesteric liquid crystal is perpendicular to a surface (first side 31) of the glass substrate. As shown in fig. 4 and 5, in conjunction with fig. 4 and 5, the device in fig. 4 is a cholesteric liquid crystal film (Cholesteric liquid crystal thin film, CLC layer), and the angle of incidence is such that the cholesteric liquid crystal film reflects incident light within an angle range that allows the cholesteric liquid crystal film to operate in a reflective mode, e.g., the angle of incidence isWhen in use; the angle value of the incident angle is such that the cholesteric liquid crystal film transmits incident light to the liquid crystal diffraction lens 321 when the cholesteric liquid crystal film is not operated in the angle range of the reflection mode, for example, the incident angle is +>When the incident angle is around 45 °, the liquid crystal selective reflection device 311 will operate in the reflection mode to diffract the incident light to a specific angle and the diffraction efficiency is as high as 100%; when the incident angle is not in the vicinity of 45 °, the liquid crystal selective reflection device 311 will operate in the transmissive mode as a uniform phase retardation wave plate. The working angle and the range of the working angle of the liquid crystal selective reflecting device 311 can be accurately adjusted by the liquid crystal parameters and the period of the cholesteric liquid crystal, so that the adjustment of the emergent direction of the irradiation laser can be realized by the liquid crystal selective reflecting device 311.

In some embodiments, the optical signal receiving module 2 may be an avalanche photodetector, the second reflected light is collimated and focused by the liquid crystal diffraction lens 321 to the avalanche photodetector, and the second reflected light collimated and focused by the liquid crystal diffraction lens 321 is detected by the avalanche photodetector.

In some embodiments, as shown in fig. 6 and 7, the phase adjustment module 4 may include a plurality of strip electrodes 42 disposed at intervals and a strip electrode power supply circuit 41 for outputting a power supply voltage to the strip electrodes 42, wherein the strip electrode power supply circuit 41 is connected to the strip electrodes 42, and liquid crystal molecules 421 or semiconductors are encapsulated between the strip electrodes 42, and the strip electrodes 42 may be metal strip electrodes, nonmetal strip electrodes or semiconductor strip electrodes. The bar electrode 42 can be determined by a person skilled in the art according to the requirements, for example, the bar electrode 42 can be an aluminum bar electrode made of aluminum; for another example, the stripe electrode 42 may be a silicon stripe electrode made of silicon.

When the embodiment is specifically applied, the power supply voltage is output to the strip electrodes 42 through the strip electrode power supply circuit 41, different power supply voltages are applied to the adjacent strip electrodes 42 to generate an electric field, the electric field changes the orientation of liquid crystal molecules 421 between the strip electrodes 42, or the carrier concentration of the indium tin oxide is changed through the electric field when the indium tin oxide is filled between the strip electrodes 42, so that the phase of the emergent electromagnetic wave between the strip electrodes 42 is changed, the propagation direction of the laser is modulated by using the phase gradient, the propagation direction of the emergent light of the first reflected light is changed, the optical device is replaced, the large-angle deflection and response of the laser are realized, and the volume and the weight of the laser radar are further reduced. Specifically, the modulation effect of the phase gradient on the propagation direction of the laser light can be determined by the following calculation formula:

。

wherein,refers to the refractive index of the medium at the incident ray; />Is the refractive index of the medium at the position of emergent light; />Is the vacuum wavelength of the incident beam; />Is the phase of the outgoing laser; />Is the angle of incidence of the light; />Is the exit angle of the light.

In one embodiment, as shown in fig. 7, three stripe electrodes 42 are provided, and liquid crystal molecules 421 are filled between any two adjacent stripe electrodes 42. As shown in fig. 7, the arrangement of three stripe electrodes 42 and the filling of the liquid crystal molecules 421 between the adjacent stripe electrodes 42 are shown, the three stripe electrodes 42 and the liquid crystal molecules 421 are in an AL-liquid crystal-AL (aluminum stripe electrode-liquid crystal-aluminum stripe electrode) liquid crystal array structure, the AL represents the stripe electrode 42 made of aluminum, and the liquid crystal represents the liquid crystal molecules 421. When the potentials on the two adjacent strip electrodes 42 are equal, at this time, there is no electric field between the two adjacent strip electrodes 42, and correspondingly, the liquid crystal molecules 421 between them are not affected by the electric field, so that the liquid crystal molecules 421 are arranged to follow the direction of surface alignment; when the electric potentials on the two adjacent strip electrodes 42 are unequal, an electric field is arranged between the two adjacent strip electrodes 42, and the liquid crystal molecules 421 between the two adjacent strip electrodes rotate along with the electric field, so that the dielectric constant between the strip electrodes 42 is changed, and the emergent phase of the liquid crystal molecules 421 is also changed along with the dielectric constant, so that the large-angle deflection and response of laser are realized.

Here, it should be noted that the rotation angle of the liquid crystal molecule 421 is proportional to the potential difference between the stripe electrodes 42, and the final direction of the liquid crystal molecule 421 after rotation is related to the kind of the material of the liquid crystal molecule 421, for example, the director of the liquid crystal molecule 421 in the positive direction will be parallel to the electric field, and the director of the liquid crystal molecule 421 in the negative direction will be perpendicular to the electric field.

In some embodiments, the strip electrode 42 has a thickness in the Z-axis direction of 50nm to 150nm, preferably 100nm. The gap 422 between adjacent stripe electrodes 42 in the x-axis direction is 100nm to 300nm, preferably 200nm. Further, a simulation software of a finite FDTD (Finite Difference Time Domain, finite difference time domain algorithm) module is adopted to simulate the two-dimensional condition of the AL-liquid crystal-AL liquid crystal array structure, and specific simulation details are as follows: one beam of incident light polarized along the x-direction vertically strikes the liquid crystal array structure of AL-liquid crystal-AL along the Z-direction, and the phase distribution of the emergent light along the x-direction is collected, wherein the thickness of each strip electrode 42 along the Z-axis direction is 100nm, and the gap 422 between the adjacent strip electrodes 42 along the x-axis direction is 200nm in width. As shown in fig. 8 and 9, fig. 8 is a graph of the gap between the stripe electrodes and the emission phase, fig. 9 is a graph of the phase angle of the liquid crystal molecules and the emission phase, in which a1 is a graph of the gap 422 between the stripe electrodes 42 and the emission phase in the x-axis direction when the plane orientation of the liquid crystal molecules 421 is 90 °, a2 is a graph of the gap 422 between the stripe electrodes 42 and the emission phase in the x-axis direction when the plane orientation of the liquid crystal molecules 421 is 80 °, a3 is a graph of the gap 422 between the stripe electrodes 42 and the emission phase in the x-axis direction when the plane orientation of the liquid crystal molecules 421 is 70 °, a4 is a graph of the gap 422 between the stripe electrodes 42 and the emission phase in the x-axis direction when the plane orientation of the liquid crystal molecules 421 is 65%, a5 is a relationship between the gap 422 between the stripe electrodes 42 in the x-axis direction and the emission phase when the orientation of the liquid crystal molecule 421 in the plane is 60 °, a6 is a relationship between the gap 422 between the stripe electrodes 42 in the x-axis direction and the emission phase when the orientation of the liquid crystal molecule 421 in the plane is 50 °, a7 is a relationship between the gap 422 between the stripe electrodes 42 in the x-axis direction and the emission phase when the orientation of the liquid crystal molecule 421 in the plane is 40 °, a8 is a relationship between the gap 422 between the stripe electrodes 42 in the x-axis direction and the emission phase when the orientation of the liquid crystal molecule 421 in the plane is 30 °, a9 is a relationship between the gap 422 between the stripe electrodes 42 in the x-axis direction and the emission phase when the orientation of the liquid crystal molecule 421 in the plane is 20 °, a10 is a relationship between the gap 422 between the stripe electrodes 42 in the x-axis direction and the emission phase, a11 is a relationship curve between the phase angle and the emission phase of the liquid crystal molecules when the gap 422 between the stripe electrodes 42 in the x-axis direction is 0.25 μm, a12 is a relationship curve between the phase angle and the emission phase of the liquid crystal molecules when the gap 422 between the stripe electrodes 42 in the x-axis direction is 0.20 μm, and a13 is a relationship curve between the phase angle and the emission phase of the liquid crystal molecules when the gap 422 between the stripe electrodes 42 in the x-axis direction is 0.15 μm. As can be seen from fig. 8 and 9, by changing the orientation of the liquid crystal molecules 421 in the plane (0-90 ° and can be controlled by the electric field intensity of the strip electrodes 42), a change of 200 ° of the emission phase can be achieved, and if the gap 422 between the adjacent strip electrodes 42 along the X-axis direction is changed, there will be a certain effect on the emission phase, but the maximum emission phase will remain around 200 °. The gap 422 between the adjacent stripe electrodes 42 along the X-axis direction is filled with liquid crystal molecules 421.

In some embodiments, as shown in fig. 10, the strip electrode power supply circuit 41 may include a core 411 for receiving an external input signal, a protocol conversion module 412, a pre-storage register 413, a signal register 414, a switch 415, a potentiometer 416, and an external capacitor 417 for outputting a power supply voltage to the strip electrode 42; wherein, the kernel 411 is connected with a pre-storage register 413 through a protocol conversion module 412; the pre-storage register 413 is connected to the signal register 414; the switch 415 is respectively connected with the potentiometer 416, the strip electrode 42 and the signal register 414; the external capacitor 417 is connected to the switch 415 via the potentiometer 416.

In this embodiment, when the orientation of the liquid crystal molecules 421 between the strip electrodes 42 needs to be changed, an external input signal for changing the orientation of the liquid crystal molecules 421 between the strip electrodes 42 may be transmitted to the protocol conversion module 412 through the core 411, the protocol conversion module 412 analyzes, converts, etc. the received external input signal, and outputs potential information matched with the protocol of the pre-storage register 413, where the potential information is stored in the pre-storage register 413, and at the same time, the pre-stored potential information of each frame is transmitted to the signal register 414, so as to control the working condition of the switch 415, so that the external capacitor 417 may supply power to the strip electrodes 42, where the working condition of the switch 415 includes both open and close conditions, and when the switch 415 is open, the external capacitor 417 does not output the power supply voltage to the strip electrodes 42; when the switch 415 is closed, the external capacitor 417 outputs a supply voltage to the strip electrode 42, and when the switch 415 is closed, the potentiometer 416 can be adjusted at the same time, so that a potential difference exists between the strip electrodes 42, and the orientation of liquid crystal molecules 421 between the strip electrodes 42 or the carrier concentration of indium tin oxide are changed, wherein the inner core 411 is connected with the outside through a USB interface.

Further, when the strip electrode 42 is mounted, it may be integrated on the same substrate as the strip electrode power supply circuit 41. Specifically, a silicon substrate or a glass substrate may be used as the mounting carrier for the strip electrode 42, and the strip electrode 42 may be disposed at the intermediate position of the strip electrode power supply circuit 41 by using the silicon substrate or the glass substrate as the mounting carrier for the strip electrode 42. When the strip electrode 42 is connected to the switch 415, the upper and lower directions of the strip electrode 42 are led out through conductors, and are connected to the switch 415 through conductors, so that the switch 415 is connected to the strip electrode 42.

In this embodiment, the strip electrode 42 is disposed in the middle of the strip electrode power supply circuit 41, which facilitates the connection between the device in the strip electrode power supply circuit 41 and the strip electrode 42.

In this embodiment, in the structure of the phase adjustment module 4, the incident first reflected light is in the waveguide before exiting, so that interference of adjacent wavebands is reduced or even avoided; through the structure of combining the super surface and the liquid crystal molecule 421, the resolution of the adjacent structural units can reach 300nm, the high resolution greatly improves the polarization efficiency, and meanwhile, the phase adjusting module 4 can reach large transmission efficiency based on the super-transmission phenomenon of the super surface.

In calculating the response time of the liquid crystal molecule 421, the calculation formula is as follows:

。

wherein,is the response time of the liquid crystal molecules; />The thickness of the liquid crystal layer is the thickness of the liquid crystal molecules; />Is the splay elastic coefficient of the liquid crystal molecules; />Is the sticking coefficient of the liquid crystal molecules.

From the above formula of liquid crystal molecule response time, it can be determined that the response speed of liquid crystal molecules is proportional to the square of the thickness of the strip-shaped electrode. When the thickness of the strip electrode along the Z axis is less than 200nm in the test, the thickness is 1/30 times of the thickness of LCOS liquid crystal (liquid crystal on silicon), and the response time is 1/900 of the LCOS liquid crystal and is about 20 mu s, so that the ultrafast response of the phase adjusting module is demonstrated.

In this embodiment, the potentiometer 416 may be a 256-stage potentiometer.

In order to better understand the lidar based on the geometric phase of liquid crystal, the application procedure of the lidar based on the geometric phase of liquid crystal in fig. 1 will be described again here: the laser emission module 1 emits laser to the laser reflection and reflection light collimation focusing module 3, the liquid crystal selective reflection device 311 in the laser reflection and reflection light collimation focusing module 3 reflects the laser to form first reflection light, the emergent direction of the first reflection light is changed by adjusting the period of the liquid crystal selective reflection device 311 on the laser reflection and reflection light collimation focusing module 3, the first reflection light is enabled to be parallel to the thickness direction of the glass substrate and irradiates to the phase adjustment module 4, the emergent direction of the first reflection light is changed again through the phase adjustment module 4, dynamic scanning is carried out on the outside, in the scanning process, after the first reflection light hits the target object 5, the second reflection light is formed by reflecting the target object 5, the second reflection light irradiates to the phase adjustment module 4, the emergent direction of the second reflection light is changed by the phase adjustment module 4, the second reflection light is enabled to be parallel to the thickness direction of the glass substrate and irradiates to the laser reflection and reflection light collimation focusing module 3, and the liquid crystal diffraction lens 321 on the laser reflection and reflection light collimation focusing module 3 collimates the second reflection light and irradiates to the optical signal receiving module 2 after focusing.

In summary, the laser radar based on the liquid crystal geometric phase provided by the utility model can be applied to application scenes such as vehicle-mounted vision cameras, vehicle-mounted infrared cameras and the like. The laser radar based on the liquid crystal geometric phase has the following effects:

the laser emission module 1 emits laser to the laser reflection and reflection light collimation focusing module 3, wherein the laser reflection and reflection light collimation focusing module 3 comprises a light-transmitting carrier 33, a liquid crystal selective reflecting device 311 for changing the outgoing direction of the laser is arranged on a first side 31 of the light-transmitting carrier 33, a liquid crystal diffraction lens 321 for collimation focusing of the reflected light is arranged on a second side 32 of the light-transmitting carrier 33, and the reflection, collimation and focusing of the laser are completed through the liquid crystal selective reflecting device 311 and the liquid crystal diffraction lens 321, so that the mode of reflecting, collimation and focusing of the laser through the cooperation of a prism, a refraction lens and a mechanical structure in the prior art is replaced, the volume and the weight of the laser radar are reduced, the laser radar is light and handy, and meanwhile, the production cost is reduced.

It is to be understood that the above examples only represent preferred embodiments of the present utility model, which are described in more detail and are not to be construed as limiting the scope of the utility model; it should be noted that, for a person skilled in the art, the above technical features can be freely combined, and several variations and modifications can be made without departing from the scope of the utility model; therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (10)

1. A liquid crystal geometric phase-based lidar comprising: the device comprises a laser emission module, an optical signal receiving module, a laser reflection and reflected light collimation focusing module and a phase adjusting module for changing the emergent direction of reflected light;

the laser reflection and reflection light collimation focusing module comprises a light-transmitting carrier, wherein the light-transmitting carrier comprises a first side and a second side opposite to the first side, the first side is provided with a liquid crystal selective reflection device for changing the laser emergent direction, and the second side is provided with a liquid crystal diffraction lens for collimation focusing of reflection light;

the laser emission module is arranged on the side surface of the laser reflection and reflection light collimation focusing module according to a preset angle;

the laser emitted by the laser emitting module irradiates onto the liquid crystal selective reflecting device, the liquid crystal selective reflecting device reflects the laser emitted by the laser emitting module to form first reflected light, the first reflected light irradiates to a target object through the phase adjusting module, the target object reflects the first reflected light to form second reflected light, and the second reflected light is collimated and focused to the optical signal receiving module through the phase adjusting module and the liquid crystal diffraction lens.

2. The liquid crystal geometric phase-based lidar of claim 1, wherein the liquid crystal selective reflection device comprises: and the spiral axis of the cholesteric liquid crystal is vertically encapsulated on the first side of the light-transmitting carrier.

3. The liquid crystal geometric phase-based lidar of claim 1, wherein the light-transmitting carrier is a glass substrate or a silicon substrate.

4. A liquid crystal geometric phase based lidar according to any of claims 1 to 3, wherein the light receiving signal module is an avalanche photodetector, and the second reflected light is collimated and focused to the avalanche photodetector after passing through the liquid crystal diffraction lens.

5. A liquid crystal geometric phase based lidar according to any of claims 1 to 3, wherein the laser emitting module comprises an edge emitting laser.

6. The liquid crystal geometric phase-based lidar of claim 1, wherein the phase adjustment module comprises: the liquid crystal display device comprises a plurality of strip electrodes arranged at intervals and a strip electrode power supply circuit for outputting power supply voltage to the strip electrodes, wherein the strip electrode power supply circuit is connected with the strip electrodes, and liquid crystal molecules or semiconductors are packaged between the strip electrodes.

7. The liquid crystal geometry phase based lidar of claim 6, wherein the strip electrode is a metal strip electrode, a non-metal strip electrode, or a semiconductor strip electrode.

8. The liquid crystal geometry phase based lidar of claim 7, wherein the strip electrode has a thickness of 50nm to 150nm along the Z-axis direction, and a gap between adjacent strip electrodes is 100nm to 300nm.

9. The liquid crystal geometric phase based lidar of any of claims 6 to 8, wherein the strip electrode power supply circuit comprises: the external capacitor is used for outputting power supply voltage to the strip-shaped electrode;

the kernel is connected with the pre-storage register through the protocol conversion module;

the pre-storage register is connected with the signal register;

the switch is respectively connected with the potentiometer, the strip-shaped electrode and the signal register;

the external capacitor is connected with the switch through the potentiometer.

10. The liquid crystal geometry phase based lidar of claim 9, wherein the strip electrode is positioned in a middle position of the strip electrode power supply circuit.