CN109444848A - Scanning means and its scan method, laser radar - Google Patents
Scanning means and its scan method, laser radar Download PDFInfo
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- CN109444848A CN109444848A CN201811254267.8A CN201811254267A CN109444848A CN 109444848 A CN109444848 A CN 109444848A CN 201811254267 A CN201811254267 A CN 201811254267A CN 109444848 A CN109444848 A CN 109444848A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4817—Constructional features, e.g. arrangements of optical elements relating to scanning
Abstract
A kind of scanning means and its scan method, laser radar, the scanning means includes: the first scanning element, first scanning element is adapted so that the direction of propagation of incident beam occurs the first deflection and forms outgoing beam, and first scanning element changes the deflection angle size of first deflection by way of rotating or swinging；Second scanning element, second scanning element is located in the optical path of at least one in the incident beam and the outgoing beam, when the incident beam or the outgoing beam transmit second scanning element, second scanning element makes the second deflection of direction of propagation generation of the light beam of transmission based on electrooptic effect.The scanning means can not only realize delay angle compensation, additionally it is possible to the time of the single that effectively shortens detection, effectively improve scan frequency, be advantageously implemented taking into account for high scan frequency and high relevant efficiency.
Description
Technical field
The present invention relates to laser acquisition fields, in particular to a kind of scanning means and its scan method, laser radar.
Background technique
Laser radar is a kind of common distance measuring sensor, has remote detection range, high resolution, little interference by environment etc.
Feature is widely used in the fields such as intelligent robot, unmanned plane, unmanned.In recent years, automatic Pilot technology is quickly grown,
Core sensor of the laser radar as its perceived distance, it is indispensable.
Major part laser radar realizes the scanning of outgoing beam continuous rotation or by way of swinging back and forth at present.It is receiving
In the laser radar on the road Fa Gong, scanning means not only needs to realize the scanning of outgoing beam, also needs to realize anti-through target to be detected
Penetrate the collection of formed echo beam.Due to the lasting rotation of scanning means, after target reflects, scanning means is received back light beam
Angle when angle when glistening light of waves beam is emitted with scanning light beam has certain difference, i.e. scanning means generates delay angle.
The size of delay angle is related at a distance from object to be measured.Particularly, in the laser radar based on coherent detection, laser
The coherent detection of radar be reflect the coherent signal realization between formed echo light based on local oscillator light and through object to be measured, and
The signal-to-noise ratio of coherent signal is proportional to the wavefront matching degree between local oscillator light and echo light.Therefore in order to improve local oscillator light and return
Relevant efficiency between the glistening light of waves is to guarantee the signal-to-noise ratio of coherent signal, it is necessary to carry out angle compensation, inhibit phase caused by delay angle
Dry efficiency decline.
But in the prior art, the laser radar system that can be realized angle compensation often has that scan frequency is too low to ask
Topic.
Summary of the invention
Problems solved by the invention is to provide a kind of scanning means and its scan method, laser radar, is guaranteeing that angle mends
While repaying effect, the scan frequency of laser radar is improved.
To solve the above problems, the present invention provides a kind of scanning means, comprising:
First scanning element, first scanning element are adapted so that the first deflection shape occurs for the direction of propagation of incident beam
At outgoing beam, the deflection angle that first scanning element changes first deflection by way of rotating or swinging is big
It is small；Second scanning element, second scanning element are located at the light of at least one in the incident beam and the outgoing beam
When Lu Zhong, the incident beam or the outgoing beam transmit second scanning element, second scanning element is based on electricity
Luminous effect makes the direction of propagation of the light beam of transmission that the second deflection occur.
Optionally, second scanning element includes electro-optic crystal, and the electro-optic crystal is linear electrooptic crystal and non-thread
At least one of property electro-optic crystal.
Optionally, the electro-optic crystal is nonlinear electrooptical crystal；The quantity of the quadratic electro-optic coefficient of the electro-optic crystal
Grade is 10-14m2/V2To 10-15m2/V2In range.
Optionally, the electro-optic crystal includes: in potassium tantalate-niobate crystal, potassium tantalate-niobate crystalline lithium and potassium tantalate-niobate sodium crystal
At least one.
Optionally, first scanning element changes the direction of propagation of the outgoing beam by way of swing, described
First scanning element includes: at least one of galvanometer and pendulum mirror；First scanning element changes institute by way of rotation
The direction of propagation of outgoing beam is stated, first scanning element includes: tilting mirror.
Optionally, first scanning element has the first reflecting surface swung around the first scan axis；Second scanning
Unit includes: the first electro-optic crystal, and second deflection includes that the first electro-optic crystal revolves the light beam of transmission around the first yawing axis
Turn；First yawing axis is parallel with first scan axis.
Optionally, first scanning element is with the first reflecting surface swung around the first scan axis and around the second scanning
The second reflecting surface that axis is swung, first scan axis and second scan axis are not parallel；The swing of first reflecting surface
The ratio of frequency and the hunting frequency of second reflecting surface is less than or equal to preset value；Second scanning element includes: edge
The first electro-optic crystal and the second electro-optic crystal that optical path is set gradually, second deflection include that the first electro-optic crystal makes transmission
Light beam is rotated around the first yawing axis；Second electro-optic crystal rotates the light beam of transmission around the second yawing axis；Described first partially
Shaft and second yawing axis are not parallel；First yawing axis is parallel to first scan axis；Second yawing axis
It is parallel to second scan axis.
Optionally, first scanning element is with the first reflecting surface swung around the first scan axis and around the second scanning
The second reflecting surface that axis is swung, first scan axis are mutually perpendicular to second scan axis；The pendulum of first reflecting surface
The ratio of the hunting frequency of dynamic frequency and second reflecting surface is greater than preset value；Second scanning element includes: the first electricity
Luminescent crystal, second deflection include that the first electro-optic crystal rotates the light beam of transmission around the first yawing axis；First deflection
Axis is parallel to first scan axis.
Optionally, second scanning element has the input face for receiving light beam incidence；Beam orthogonal is projected to described defeated
Enter face.
Optionally, second scanning element includes electro-optic crystal；The electro-optic crystal receives modulation voltage to realize
State the second deflection；The modulation voltage is less than 100V.
Optionally, the outgoing beam is suitable for forming the scanning light beam being emitted from the scanning means, the scanning light
Beam reflects to form echo beam through target to be detected；Light beam is collected in the acquired formation of echo beam；The collection light beam warp
First scanning element and second scanning element deflection are to form signal beams；The collection light beam and the incident light
Shu Gonglu.
Optionally, first scanning element changes the deflection angle of first deflection by continuous rotation or swing
Size.
Correspondingly, the scanning means is scanning of the invention the present invention also provides a kind of scan method of scanning means
Device, the scan method include:
Make the incident beam that the first deflection occur to form outgoing beam using first scanning element；Make described
One scanning unit rotational is swung to change the deflection angle size of first deflection；Tune is provided to second scanning element
Voltage processed makes the direction of propagation for the light beam for transmiting second scanning element be based on the second deflection of electrooptic effect generation and is prolonged with compensating
Delay angle.
Optionally, the deflection angle of second deflection is in cyclically-varying；The variation of the second deflection deflection angle
Period is the electro-optical deflection period；In the electro-optical deflection period, the deflection angle of second deflection is changed linearly.
Optionally, the deflection angle of second deflection is in cyclically-varying；The variation of the second deflection deflection angle
Period is the electro-optical deflection period；Second scanning element includes electro-optic crystal；In the electro-optical deflection period, the modulation electricity
Pressure changes linearly the refractive index of the electro-optic crystal at any time.
Optionally, second scanning element includes secondary electro-optic crystal；In the electro-optical deflection period, the modulation electricity
Pressure square changes linearly at any time.
Optionally, first scanning element occurs continuous rotation or swings；The deflection angle of first deflection
Consecutive variations.
In addition, the present invention also provides a kind of laser radars, comprising: scanning means of the invention.
Optionally, the laser radar is coherent laser radar.
Compared with prior art, technical solution of the present invention has the advantage that
In technical solution of the present invention, first scanning element makes the direction of propagation of the incident beam that the first deflection occur
And change the direction of propagation of the outgoing beam by way of rotating or swinging；Second scanning element is based on electrooptic effect
Make the direction of propagation of the light beam of transmission that the second deflection occur to compensate delay angle.The deflection angle size and list of second deflection
Produced delay angle is equal in magnitude in secondary detection process, and deflection is contrary, therefore the second deflection of light beam can be in single
It is compensated delay angle in detection process, so first deflection and second deflection can make the incident beam inclined
The optical path for going to the outgoing beam remains unchanged, and then guarantees that the optical path of the received light beam of scanning means is swept with described in
The optical path of the light beam of imaging apparatus outgoing remains unchanged；Moreover, because electrooptic effect is to the variation of electric signal response with higher
Rate, therefore in second deflection, the change of direction of beam propagation is to the electric signal speed of response with higher, and described second
Scanning element can realize delay angle compensation at faster speed.So technical solution of the present invention can be mended guaranteeing delay angle
It repays under the premise of effect maintains optical path constant, the time of the single that effectively shortens detection is conducive to improve scan frequency, be conducive to
Realize taking into account for high scan frequency and high relevant efficiency.
In optinal plan of the present invention, the electro-optic crystal is nonlinear electrooptical crystal；The secondary electric light of the electro-optic crystal
The order of magnitude of coefficient is 10-14m2/V2To 10-15m2/V2In range；For example, potassium tantalate-niobate crystal, potassium tantalate-niobate crystalline lithium and tantalum
At least one of potassium-sodium niobate crystal.The electro-optic coefficient of the electro-optic crystal is larger, and the electro-optic coefficient of electro-optic crystal is bigger, phase
With under voltage, the variations in refractive index of electro-optic crystal is bigger, therefore setting electro-optic coefficient is biggish in second scanning element
Electro-optic crystal can be realized biggish variations in refractive index, be kept the deflection angle of the second deflection larger with lesser voltage, so
The use of big electro-optic coefficient electro-optic crystal, can be effectively reduced the modulation voltage for realizing electrooptic effect, thus guaranteeing delay angle
Under the premise of compensation, achieve the purpose that low-voltage high-frequency.
In optinal plan of the present invention, be rationally arranged according to the scanning direction of first scanning element and scanning speed described in
The position of electro-optic crystal in second scanning element can make the deflection direction of the second deflection and the deflection direction of first deflection
Match, keeps the deflection direction of second deflection and the deflection direction of first deflection parallel to each other, can effectively enhance
Influence of second deflection to the outgoing beam direction of propagation, expands the deflection angle of the formed scanning light beam direction of propagation
Degree, can be formed the scanning light beam of larger deflection angle, can be effectively reduced and be applied to the electro-optic crystal with lesser voltage
On modulation voltage, be advantageously implemented low-voltage high-frequency scanning purpose.
In optinal plan of the present invention, the modulation voltage is less than 100V.The size for controlling modulation voltage, can be effectively reduced
The control voltage of the scanning means is advantageously implemented the purpose of low-voltage high-frequency scanning, is conducive to meet mobile lidar
Technical need.
In optinal plan of the present invention, first scanning element makes the incident beam that reflection occur to form the outgoing
Light beam；Second scanning element is located in the optical path of the incident beam, i.e., described first scanning element is to through the second deflection
The incident beam carry out first deflection form the outgoing beam, deflection of the incident beam in the second deflection process
Angle can be amplified in first deflection process, so as to be formed more with the deflection angle of lesser second deflection
The outgoing beam of large deflection angle degree, and then the scanning light beam of larger deflection angle can be obtained, it can be effectively reduced and cause electric light
Voltage needed for effect is advantageously implemented the purpose of low-voltage high-frequency scanning, is conducive to the technical need for meeting mobile lidar.
Detailed description of the invention
Fig. 1 is the light channel structure schematic diagram of scanning means first embodiment of the present invention；
Fig. 2 is the light channel structure schematic diagram of scanning means second embodiment of the present invention；
Fig. 3 is the time diagram of signal employed in one embodiment of scan method of the present invention；
Fig. 4 be in scan method embodiment shown in Fig. 3 first deflection deflection angle, second deflection deflection angle and
The relational graph of scanning angle and time.
Specific embodiment
It can be seen from background technology that can be realized the laser radar system of angle compensation in the prior art, there are scan frequency mistakes
Low problem.The reason of analyzing its scan frequency too low problem now in conjunction with the method that laser radar system realizes angle compensation:
At present in laser radar, the method for delay angle is inhibited to be broadly divided into two classes: step-scan and local angle compensation.Its
In, step-scan refers to that, using discrete scanning mode, scanning means remains unchanged in single detection process, until next
Secondary detection.Specifically, existing laser radar by means of the realization of the electro-optical devices such as stepper motor or liquid crystal optical waveguide by sweeping
It retouches.
Local angle compensation refers to while scanning means scanning, adjusts local oscillator light in real time using another reflection unit
Direction, with guarantee local oscillator light and signal light wavefront matching；And the way that reflection unit adjusts local oscillator light direction in real time is usual
It is realized by means of servo motor.
The either mode of step-scan, or the mode of local angle compensation, in the skill for taking into account angle compensation and scanning
In art scheme, the frequency of scanning can all be limited by existing electric machine frequency, so that it is longer single detection time occur, be mostly
The shortcomings that millisecond magnitude.
Especially in automatic Pilot field, the frame frequency of laser radar and the technical requirements of spatial resolution are higher, single
Detection time is very short, is mostly several microseconds, therefore traditional stepper motor or servo motor has been unable to satisfy demand, thus
There is the problem that scan frequency is too low, single detection time is too long.
To solve the technical problem, the present invention provides a kind of scanning means, comprising:
First scanning element, first scanning element are adapted so that the first deflection shape occurs for the direction of propagation of incident beam
At outgoing beam, first scanning element changes the direction of propagation of the outgoing beam by way of rotating or swinging；
Second scanning element, second scanning element are located at the optical path of at least one in the incident beam and the outgoing beam
In, when the incident beam or the outgoing beam transmit second scanning element, second scanning element is based on electric light
Effect makes the direction of propagation of the light beam of transmission that the second deflection occur.The scanning means can not only be realized in single detection process
Delay angle compensation, additionally it is possible to the time of the single that effectively shortens detection, effectively improve scan frequency, be advantageously implemented high scanning frequency
Rate is taken into account with high relevant efficiency.
To make the above purposes, features and advantages of the invention more obvious and understandable, with reference to the accompanying drawing to the present invention
Specific embodiment be described in detail.
With reference to Fig. 1, the light channel structure schematic diagram of scanning means first embodiment of the present invention is shown.
The scanning means 100 includes:
First scanning element 110, first scanning element 110 are adapted so that the direction of propagation of incident beam 121 occurs
First deflection forms outgoing beam 119, and first scanning element 110 changes the outgoing by way of rotating or swinging
The direction of propagation of light beam 119；Second scanning element 120, second scanning element 120 are located at the incident beam 121 and institute
In the optical path for stating at least one in outgoing beam 119, the incident beam 121 or the outgoing beam 119 transmit described second
When scanning element 120, second scanning element 120 occurs second partially based on the direction of propagation for the light beam that electrooptic effect makes to transmit
Turn.
The deflection angle size of second deflection is equal with delay angle generated in detection process, deflects direction phase
Instead, thus light beam second deflection delay angle can be made to be compensated in single detection process, so it is described first deflection and
The optical path that second deflection can make the incident beam 121 deflect to the outgoing beam 119 remains unchanged, and then guarantees
The optical path of the received light beam of the scanning means 100 and the optical path for the light beam being emitted from the scanning means 100 remain unchanged.
Moreover, because electrooptic effect is to the variation of the electric signal speed of response with higher, therefore in second deflection,
To the electric signal speed of response with higher, second scanning element 120 can be with faster for the change of direction of beam propagation
Velocity interpolation postpones angle compensation.
So the scanning means 100 can have under the premise of guaranteeing that delay angle compensation effect maintains optical path constant
The time of effect shortening single detection, be conducive to improve scan frequency, be advantageously implemented high scan frequency and high the simultaneous of efficiency of being concerned with
It cares for.
As shown in Figure 1, the scanning means 100 receives the incipient beam of light 138 that R-T unit 130 generates in the present embodiment,
To form the incident beam 121.
In the present embodiment, the R-T unit 130 and the scanning means 100 are the R-T unit in coherent laser radar
And scanning means, therefore the R-T unit 130 is relevant R-T unit, to obtain fine angular resolution, High Range Resolution, strong
The advantages such as anti-interference ability.So from the optical path between the light source (not shown) and the scanning means 100 for generating light beam
In be additionally provided with light-dividing device (not shown), the light-dividing device is used to form local beam to carry out coherent detection.Tool
Body, the present invention does not limit the formation of the local beam.
It should be noted that the scanning means 100 can also include the diaphragm not showed that in Fig. 1, lens or saturating
Other optical components such as microscope group form the incident beam 121 to receive the incipient beam of light 138.
First scanning element 110 makes the first deflection of direction of propagation generation of the incident beam 121 form emergent light
Beam 119, and change the described first deflection angle size deflected by way of rotating or swinging, to form the direction of propagation not
Same outgoing beam 119.
In the present embodiment, first scanning element 110 changes the propagation of the outgoing beam 119 by way of swing
Direction, first scanning element 110 include: at least one of galvanometer and pendulum mirror.
Specifically, first scanning element 110 includes: galvanometer.Galvanometer has high-precision, high speed and high integration
The characteristics of, therefore galvanometer is set by first scanning element 110, the scanning means 100 can not only be effectively improved
Scan frequency, additionally it is possible to the integrated level and optical path precision of active control unit.
First scanning element 110 makes the incident beam 121 that reflection occur to form the outgoing beam 119.Tool
Body, as shown in Figure 1, first scanning element 110 includes one-dimensional galvanometer.First scanning element 110 has around first
The first reflecting surface (not indicated in figure) that scan axis 117 is swung.The incident beam 121 occurs instead on first reflecting surface
It penetrates to form the outgoing beam 119.
It should be noted that it is only one real that the way that first scanning element 110 is galvanometer, which is arranged, in the present embodiment
Example.In other embodiments of the invention, first scanning element may be arranged as pendulum mirror.In addition, other implementations of the present invention
In example, first scanning element changes the direction of propagation of the outgoing beam by way of rotation, and first scanning is single
Member includes: tilting mirror.
With the swing of first reflecting surface, the incident beam 121 is projected to the incidence angle of first reflecting surface
Size can change therewith, and the angle of reflection size of formed outgoing beam 119 also changes therewith, i.e., the deflection angle of described first deflection
Degree size can change with the swing of first reflecting surface, to make the direction of propagation of formed outgoing beam 119
Change therewith.
In the present embodiment, first scanning element 110 is by continuous rotation or swings change first deflection
Deflection angle size.Make 110 continuous rotation of the first scanning element or swings to change the deflection angle of first deflection
Size is spent, the rotation of the first scanning element 110 is avoided or swings the limitation by electric machine frequency, thus to shorten single detection
Time, raising scan frequency create conditions.
Specifically, as shown in Figure 1, first reflecting surface is around the continuously swing of the first scan axis 117, the incident light
Continuous cyclically-varying can be presented in the incidence angle size that beam 121 is projected to first reflecting surface, the outgoing beam 119
Periodic consecutive variations can be also presented in angle of reflection size.
Second scanning element 120 is located at the light of at least one in the incident beam 121 and the outgoing beam 119
On the road, second scanning element 120 is suitable for transmiting the incident beam 121 or the outgoing beam 119, and is based on electric light
Effect makes the direction of propagation of the light beam of transmission that the second deflection occur to compensate delay angle.
The deflection angle size and delay angle of second deflection are equal in magnitude, contrary, so as to visit in single
Delay angle is compensated during survey；In single detection process, first deflection and second deflection can make institute
It states incident beam 121 and deflects to the optical path of the outgoing beam 119 and remain unchanged, and then guarantee that the scanning means 100 receives
The optical path of light beam and the optical path for the light beam being emitted from the scanning means 100 remain unchanged.
Although it can be seen that the deflection angle size of first deflection can turn with first scanning element 110
Dynamic or swing changes, and the deflection angle size of second polarization can be based on the electrooptic effect in second scanning element 120
And change, but in single detection process, the angle of first deflection and the second deflection synthesis remains constant, i.e. institute
It states incident beam 121 to the deflection angle between the outgoing beam 119 and remains constant, that is to say, that the scanning means 100
Equivalent light path remain unchanged；Therefore, in single detection process, from the optical path of the received light beam of the scanning means 100 with
The optical path for the light beam being emitted from the scanning means 100 remains unchanged, the propagation side for the light beam being emitted from the scanning means 100
It is constant to maintenance.
As shown in Figure 1, in single detection process, first deflection and second deflection can in the present embodiment
It maintains between the incipient beam of light 138 and scanning light beam 190 that optical path is constant, guarantees that 190 direction of propagation of scanning light beam is constant.
Moreover, it is described second deflection be occurred based on electrooptic effect, therefore second deflection in, direction of beam propagation
Change to the electric signal speed of response with higher, second scanning element 120 can realize delay angle at faster speed
Compensation.Quickly delay angle compensation makes it possible to shorten the time for maintaining 100 equivalent light path of scanning means constant, make
Maintain 100 equivalent light path of scanning means it is constant get rid of electric machine frequency limitation be possibly realized, thus be conducive to shorten single detection
Time is conducive to improve scan frequency, is advantageously implemented taking into account for high scan frequency and high relevant efficiency.
In the present embodiment, first scanning element 110 is by continuous rotation or swings change first deflection
Deflection angle size.Therefore the scanning means 100 can get rid of the electric machine frequencies such as servo motor, stepper motor to scan frequency
Limitation, be advantageously implemented taking into account for high scan frequency and high relevant efficiency.
Specifically, electrooptic effect refers to the phenomenon that refractive index of substance changes because of extra electric field, electrooptic effect packet
Include Pockels effect (Pockels Effect) and Kerr effect (Kerr Effect).Wherein, refractive index and extra electric field are strong
The first power of degree is directly proportional and is Pockels effect or linear electro-optic effect the phenomenon that change；Refractive index and electric field strength
Quadratic power it is directly proportional and be Kerr effect or quadratic electro-optical effect the phenomenon that change.
Electrooptic effect is to the variation of the electric signal speed of response with higher, therefore the deflection angle pair of second deflection
The electric signal speed of response with higher, so second scanning element 120 can realize that delay angle is mended at faster speed
It repays；So the scanning means 100 can effectively contract under the premise of guaranteeing that delay angle compensation effect maintains optical path constant
The time of short single detection is advantageously implemented high scan frequency and high the simultaneous of efficiency of being concerned with to be conducive to improve scan frequency
It cares for.
Wherein, second scanning element 120 includes electro-optic crystal, and the electro-optic crystal is linear electrooptic crystal and non-thread
At least one of property electro-optic crystal.Specifically, the incident beam 121 occurs during transmiting the electro-optic crystal
Two deflections.
It should be noted that second scanning element 120 has the input face for receiving light beam incidence；Beam orthogonal projection
To the input face.Keep beam orthogonal incident, can effectively simplify the optical path of the scanning means 100, advantageously reduce optical path
Adjustment difficulty.
In the present embodiment, the electro-optic crystal is nonlinear electrooptical crystal；The quadratic electro-optic coefficient of the electro-optic crystal
The order of magnitude is 10-14m2/V2To 10-15m2/V2In range.Wherein, the electro-optic crystal includes: potassium tantalate-niobate crystal, potassium tantalate-niobate
At least one of crystalline lithium and potassium tantalate-niobate sodium crystal.
The electro-optic coefficient of the electro-optic crystal is larger, and the electro-optic coefficient of electro-optic crystal is bigger, under identical voltage, electro-optic crystal
Variations in refractive index it is bigger, therefore the biggish electro-optic crystal of electro-optic coefficient is set in second scanning element 120, can be with
Lesser voltage realizes biggish variations in refractive index, keeps the deflection angle of the second deflection larger, that is to say, that realize identical
The deflection of angle, voltage required for the electro-optic crystal of larger electro-optic coefficient is smaller, so the use of big electro-optic coefficient electro-optic crystal,
It can be effectively reduced and guarantee that delay angle compensation effect maintains the constant required voltage of optical path, to reach the mesh of low-voltage high-frequency
's.
In the present embodiment, the electro-optic crystal is potassium tantalate-niobate.Potassium tantalate-niobate crystal is currently known with maximum two
The crystal of secondary electro-optic coefficient.The potassium tantalate-niobate crystal is set by the electro-optic crystal, in the feelings for generating equal deflection angle
Under condition, required voltage can be effectively reduced, to reach the scanning effect of low-voltage high-frequency.
In the present embodiment, second scanning element 120 is located in the optical path of the incident beam 121, and described first sweeps
It retouches 110 pairs of incident beams 121 through the second deflection of unit and carries out the first deflection to form the outgoing beam 119.
In the present embodiment, second scanning element 120 is set to way in the optical path of the incident beam 121 only
For an example.In other embodiments of the invention, second scanning element also be can be set in the optical path of the outgoing beam.
The incident beam forms the outgoing beam after by the first deflection, and outgoing beam transmission second scanning is single
Member；During transmiting second scanning element, the outgoing beam is by the second deflection to form the scanning light beam
And realize delay angle compensation.
As shown in Figure 1, first scanning element 110 includes one-dimensional galvanometer, first scanning element 110 passes through around the
Incident beam 121 described in the first reflective surface that one scan axis 117 is swung forms the outgoing beam 119.Therefore, described
Two scanning elements 120 include: the first electro-optic crystal 129, and second deflection includes the light beam that the first electro-optic crystal 129 makes transmission
It is rotated around the first yawing axis；First yawing axis is parallel with first scan axis 117.
First yawing axis is parallel with first scan axis 117, and first scan axis 117 is sent out perpendicular to light beam
The plane of incidence (plane of incidence refers to the plane that normal is constituted at incident light and incidence point) in raw second deflection process can make institute
The deflection direction in the deflection direction and second deflection of stating the first deflection matches, and the incident beam 121 is deflected through second
The incident beam 121 and the outgoing beam 119 it is coplanar.This way can effectively enhance second deflection to described
The influence of 119 direction of propagation of outgoing beam can obtain the outgoing beam 119 of larger angle variation, energy by lesser voltage
Required voltage is enough effectively reduced, the purpose of low-voltage high-frequency scanning is advantageously implemented.
Specifically, first electro-optic crystal 129 is wedge shaped, there is orthogonal first right-angle surface (not indicating in figure)
Directly with the second right-angle surface (not indicated in figure) and connection first right-angle surface and second right-angle surface and with described first
Opposite the first inclined-plane (not indicated in figure) of edged surface.First right-angle surface is towards the R-T unit 130, the incident beam
121 perpendicular projections are to first right-angle surface；The incident beam 121 is arranged second right-angle surface in parallel；The incident light
Beam 121 reflects on first inclined-plane, and the second deflection occurs, is emitted from first electro-optic crystal 129.
As shown in Figure 1, the scanning means 100 receives the incipient beam of light 138 that the R-T unit 130 generates, to be formed
The incident beam 121；The incident beam 121 transmits the first electro-optic crystal 129 in second scanning element 120, warp
First scanning element 110 is projected to after second deflection.So second scanning element 120 is located at described first
In optical path between scanning element 110 and the R-T unit 130.
It should be noted that second scanning element 120 makes the light beam of transmission that the second deflection occur based on electrooptic effect,
Second scanning element 120 includes electro-optic crystal；The electro-optic crystal receives modulation voltage to realize second deflection.Its
In, the modulation voltage is less than 100V.The size for controlling modulation voltage, advantageously reduces the voltage of the scanning means 100, has
Conducive to the purpose for realizing low-voltage high-frequency scanning, be conducive to the technical need for meeting mobile lidar.
So the scanning means 100 can also include: control unit (not shown), described control unit is suitable for
In to the electro-optic crystal provide modulation voltage to realize the electrooptic effect.Described control unit and second scanning element
120 are connected, and are suitable for providing the modulation voltage to second scanning element 120, so that 120 base of the second scanning element
The second deflection is realized in light beam of the electrooptic effect to transmission.
In addition, described control unit can also be connected with first scanning element 110, the control in the present embodiment
Unit may also be adapted to control the rotation or swing of first scanning element 110, to obtain higher scan frequency and angular resolution
Rate.
It continues to refer to figure 1, the outgoing beam 119 is suitable for forming the scanning light beam being emitted from the scanning means 100
190, the scanning light beam 190 reflects to form echo beam (not indicating in figure) through target (not shown) to be detected.
In the present embodiment, the scanning means 100 is applied to receive and dispatch in the coherent laser radar on road altogether, the scanning means
100 may also be adapted to receive echo beam to form signal beams；The R-T unit 130 may also be adapted to receive signal beams progress
Coherent detection.
So light beam (not indicating in figure) is collected in the acquired formation of echo beam；The collection light beam is through described
One scanning element 110 and second scanning element 120 deflection are to form signal beams (not indicating in figure)；The collection light beam
Road is total to the incident beam 121.
It should be noted that the scanning means 100 can also include the diaphragm not showed that in Fig. 1, lens or saturating
Other optical elements such as microscope group acquire echo beam to form the collection light beam, and the collection light beam is scanned through described first
Unit 110 and second scanning element 120 deflection are to form the signal beams being emitted towards the R-T unit 130；It is described
R-T unit 130 receives the signal beams, and combines local beam, carries out coherent detection.
Since the second deflection can be realized the compensation of delay angle, first deflection and second deflection can guarantee institute
The optical path of the optical path and the light beam being emitted from the scanning element of stating the received light beam of scanning means 100 remains unchanged, therefore institute
It states echo beam and deflects to the optical paths of the signal beams and also remain unchanged；And it is reflected to form in the scanning light beam 190
During the echo beam, the optical path of the received light beam of scanning means and the light beam from scanning element outgoing
Optical path also remains unchanged.
So in single detection process, from the incipient beam of light 138, the extremely incident beam 121, the extremely outgoing
Light beam 119, the extremely scanning light beam 190, the extremely echo beam, the extremely described collection light beam and the light to the signal beams
Road remains unchanged always, it can be seen that, although the deflection angle of first deflection and the deflection angle of second deflection are equal
Changing, the equivalent light path of the scanning means 100 remains unchanged always in single detection process, i.e., the described scanning means
100 are equivalent to and are being scanned in a stepping manner.
It is scanned using the scanning means 100, delay angle can be effectively reduced, inhibit the adverse effect of delay angle,
Be conducive to improve relevant efficiency decrease problem caused by delay angle, and the electricity such as servo motor or stepper motor can be got rid of
Limitation of the unit frequency to scan frequency is conducive to the time for shortening single detection, is conducive to improve scan frequency, be advantageously implemented
High scan frequency is taken into account with high relevant efficiency.
With reference to Fig. 2, the light channel structure schematic diagram of scanning means second embodiment of the present invention is shown.
The present embodiment and previous embodiment something in common, details are not described herein by the present invention.The present embodiment and previous embodiment
The difference is that the first scanning element (not shown) has the first reflecting surface swung around the first scan axis 217x
(not shown) and the second reflecting surface (not shown) that 217y is swung around the second scan axis, first scan axis
217x and the second scan axis 217y are not parallel.
In the present embodiment, first scanning element is at least one of 2-D vibration mirror and two one-dimensional galvanometers, with control
Optical system complexity processed, and the scanning of target in different range is realized simultaneously.
In addition, the flutter rate of first reflecting surface is close with the flutter rate of second reflecting surface, described
The ratio of the hunting frequency of one reflecting surface and the hunting frequency of second reflecting surface is less than or equal to preset value (for example, described
Preset value can be set to 1 or so numerical value).It is realized with the swing of the first reflecting surface on the first scanning direction of scanning and with the
Two reflectings surface swing and realize the second scanning direction of scanning and will appear delay angle problem.
As shown in Fig. 2, second scanning element 220 includes: the first electro-optic crystal 229a and second along optical path setting
Electro-optic crystal 229b, second deflection include that the first electro-optic crystal 229a revolves the light beam of transmission around the first yawing axis 229ax
Turn；The second electro-optic crystal 229b rotates the light beam of transmission around the second yawing axis 229by；The first yawing axis 229ax
It is not parallel with the second yawing axis 229by；The first yawing axis 229ax is parallel to the first scan axis 217x；It is described
Second yawing axis 229by is parallel to the second scan axis 217y.In the present embodiment, the first scan axis 217x and described the
Two scan axis 217y are mutually perpendicular to, therefore the first yawing axis 229ax and the second yawing axis 229by is also mutually perpendicular to.
The first yawing axis 229ax is set to be parallel to the first scan axis 217x；Keep the second yawing axis 229by flat
Row is in the second scan axis 217y, that is to say, that the first scan axis 217x transmits the first electro-optic crystal perpendicular to light beam
The plane of incidence of 229a, the second scan axis 217y transmit the plane of incidence of the second electro-optic crystal 229a perpendicular to light beam, so as to
Second deflection and the direction of first deflection is enough set to match, so that reaching enhancing second deflection influences, expands
The purpose of deflection angle, and then realize the effect that larger deflection angle is formed with lesser voltage, modulation voltage is advantageously reduced,
Be conducive to the realization of low-voltage high-frequency scanning.
In the present embodiment, the first electro-optic crystal 229a and the second electro-optic crystal 229b are wedge shape, and described
First electro-optic crystal 229a and the second electro-optic crystal 229b are arranged in a mutually vertical manner.
Specifically, the first electro-optic crystal 229a has orthogonal first right-angle surface (not indicating in figure) and second
Right-angle surface (not indicated in figure) and connect first right-angle surface and second right-angle surface and with the first right-angle surface phase
The inclined-plane (not indicated in figure) of back；The second electro-optic crystal 229b has orthogonal first right-angle surface (not indicating in figure)
Directly with the second right-angle surface (not indicated in figure) and connection first right-angle surface and second right-angle surface and with described first
The opposite inclined-plane of edged surface (not indicated in figure).
First right-angle surface phase of the first right-angle surface of the first electro-optic crystal 229a and the second electro-optic crystal 229b
It is mutually parallel；The second right-angle surface of the first electro-optic crystal 229a and the second right-angle surface of the second electro-optic crystal 229b are mutual
Vertically；The inclined-plane of the first electro-optic crystal 229a is parallel to each other with the first scan axis 217x；Second electro-optic crystal
The inclined-plane of 229b is parallel to each other with the second scan axis 217y.
It should be noted that in the present embodiment, the pendulum of the flutter rate of first reflecting surface and second reflecting surface
The way that dynamic rate is close is only schematic example.In other embodiments of the invention, first scanning element can also be with fast
The mode of slow axis is scanned, i.e., the flutter rate of described first reflecting surface differed with the flutter rate of second reflecting surface compared with
Greatly.Specifically, the ratio of the hunting frequency of first reflecting surface and the hunting frequency of second reflecting surface is greater than preset value
(for example, the preset value can be set to the relatively large numerical value such as 5,8,10,20,50).
According to the principle that delay angle occurs, realized with the swing of the first reflecting surface on the first scanning direction of scanning and with the
Although two reflectings surface swing and realize the second scanning direction of scanning and will appear delay angle problem, the first scanning side
Upward delay angle problem is seriously more many than the delay angle problem on second scanning direction, that is to say, that in such case
Under, delay angle problem mainly appears on first scanning direction.
So second scanning element includes: when first scanning element is scanned in a manner of fast and slow axis
One electro-optic crystal, second deflection include that the first electro-optic crystal rotates the light beam of transmission around the first yawing axis；Described first
Yawing axis is parallel to first scan axis.When being scanned in a manner of fast and slow axis, with first electro-optic crystal improvement
Delay angle problem on first scanning direction, to can either suitably improve delay angle adverse effect, additionally it is possible to simplify light
System structure is learned, integrated level is improved, reduces cost, is advantageously implemented taking into account for performance and cost.
The present invention also provides a kind of scan methods of scanning means.
It should be noted that the scan method is the scan method based on scanning means of the present invention.In conjunction with reference Fig. 3,
Fig. 3 shows the time diagram of the used signal of one embodiment of scan method of the present invention.
It should be noted that scanning means used by the scan method is scanning means of the invention.So in conjunction with
With reference to Fig. 1, the light channel structure schematic diagram of the used scanning means 100 of scan method embodiment shown in Fig. 3 is shown.By being adopted
Scanning means 100 is scanning means of the invention, therefore the specific technical solution of the scanning means 100 is swept with reference to aforementioned
The embodiment of imaging apparatus 100, details are not described herein by the present invention.
The scan method includes: to make the incident beam 121 that the first deflection occur using first scanning element 110
To form outgoing beam 119；First scanning element 110 is set to rotate or swing to change the deflection angle of first deflection
Size.
In conjunction with reference Fig. 3 (A), Fig. 3 (A) shows the pulse train schematic diagram of the incident beam 121, abscissa in figure
For time t, unit is × 10-3s；The intensity of ordinate expression incident beam 121.
In the present embodiment, the scan method be applied to coherent laser radar in, the laser radar using light pulse into
Row scanning.Therefore the incident beam 121 is pulse signal.
As shown in figures 1 and 3, after the R-T unit 130 generates light pulse signal, the incipient beam of light 138 is described
The reception of scanning means 100 forms the incident beam 121, and the incident beam 121 is formed out through the scanning means 100 deflection
Irradiating light beam 119, and then form scanning light beam 190 and emit from the scanning means 100；The scanning light beam 190 is through mesh to be detected
Mark the echo beam reflected to form；The echo beam forms signal beams quilt after the scanning means 100 is collected and is deflected
The R-T unit 130 receives.One light pulse is single detection process from received process is emitted to.
As shown in figure line 31 in Fig. 3 (A), in ta、tbAnd tcMoment generates a light pulse signal respectively；taMoment is to tb
Moment and tbMoment is to tcTime interval between moment is sweep time, and in the present embodiment, sweep time is equal.
When first scanning element 110 rotates or swings, the deflection angle of the first deflection occurs for light beam
It can change therewith.In the present embodiment, as the first reflecting surface is along the swing of first scan axis 117, the incident light
The incidence angle that beam 121 is projected to first reflecting surface can change therewith, correspondingly, the outgoing of formed outgoing beam 119 is anti-
Firing angle also accordingly changes therewith, and then forms the scanning light beam 190 of direction of propagation variation.
As shown in Fig. 3 (C), the first deflection deflection angle in scan method embodiment shown in Fig. 1 is respectively illustrated in Fig. 3 (C)
Degree and the second deflection deflection angle and time chart.In figure, abscissa indicates the time；Ordinate indicates beam deflection angle degree,
Figure line 33 indicates the relationship of the deflection angle time of the first deflection.
In the present embodiment, the rotation or swing of first scanning element 110 are continuous, i.e., the described first scanning list
Member 110 occurs continuous rotation or swings, that is to say, that as shown in Figure 1, first reflecting surface is around first scan axis
117 occur continuous swing.Therefore the deflection angle consecutive variations of first deflection.
Specifically, the deflection angle of incident beam 121 is the SIN function about the time during the first deflection,
That is:
Wherein, f is the frequency that the first reflecting surface described in the first scanning element 110 is swung around first scan axis 117,It is for the initial phase of first reflecting surface, A is the angle of oscillation amplitude of the first reflecting surface.
Since the incident beam 121 is pulsed light beam, the sweep time is less than the pendulum of first scanning element 110
The dynamic period, therefore in each swing period of first scanning element 110, there is n times detection, so the sweep time
Are as follows: 1/Nf, the angular range that the scanning light beam 190 being emitted in n-th detection process from the scanning means 100 is inswept are as follows:
On the other hand, in the present embodiment, the scan method is applied to receive and dispatch in the laser radar on road altogether, the scanning dress
Set 100 may also be adapted to receive echo beam to form signal beams, therefore the angular dimension that the scanning light beam 190 is inswept,
As in n-th detection process, generated delay angle, are as follows:
The reason according to caused by delay angle is it is found that the size of delay angle is related at a distance from object to be measured；And in reality
In detection process, the position of object to be measured is unknown when detection starts every time, therefore can not achieve to treat and survey target progress
Angle compensation, so the problem of in order to improve delay angle, need detect start while, that is, start to compensate, i.e., every
In the entire time range of secondary detection process, guarantee the optical path of the received light beam of the scanning means 100 with from the scanning singly
The optical path of the light beam of 100 outgoing of member remains unchanged.
The scan method further include: the second scanning element of Xiang Suoshu 120 provides modulation voltage, makes to transmit described second and sweep
The direction of propagation for retouching the light beam of unit 120 is based on electrooptic effect and the second deflection occurs to compensate delay angle.
So second scanning element 120 makes produced second deflection in n-th detection process of the light beam of transmission
Deflection angle are as follows:
It can be seen that the deflection angle of second deflection is in cyclically-varying；The change of the second deflection deflection angle
The change period is the electro-optical deflection period, and as shown in Fig. 3 (C), figure line 34 indicates the deflection angle and the relationship of time of the second deflection,
The electro-optical deflection period refers to time of the deflection angle of adjacent second deflection twice between zero.It should be noted that
The deflection angle of second deflection is zero to be meant that the angular deflection due to caused by electrooptic effect is zero, is not included in
Angular deflection caused by other optical effects such as refraction, reflection.
Specifically, the electro-optical deflection period is equal with the sweep time in the present embodiment, to guarantee detecting every time
Entire time range in, keep scanning light beam 190 and echo beam deflection angle it is constant.
In the present embodiment, the scanning means 100 is suitable for carrying out uniform speed scanning, the angular scanning speed of the scanning light beam
It is that uniformly, the deflection angle variation of the first deflection is uniform.Due to the sweep time are as follows: 1/Nf, so, it is swept first
It retouches in the n-th detection process in each swing period of unit 110, the deflection angle rate of change of second deflection are as follows:
It is possible thereby to know, as shown in figure line 34 in Fig. 3 (C), the deflection angle and the relationship of time of second deflection
Are as follows:
In the present embodiment, in the electro-optical deflection period, the deflection angle of second deflection is changed linearly.Second partially
The deflection angle linear change turned can not only guarantee delay angle compensation effect, improve relevant efficiency, and optical path change rule
Simply, scan control difficulty is lower, is conducive to the precision for improving optical path setting.
Specifically, second scanning element 120 includes electro-optic crystal, the modulation voltage is applied to the electro-optic crystal
On to cause the electrooptic effect of the electro-optic crystal.As shown in Figure 1, in second scanning element 120, the first electro-optic crystal
129 shape is wedge shape, and the incident beam 121 is being emitted first electro-optic crystal when transmiting the first electro-optic crystal 129
Refraction occurs for 129 surface to realize second deflection.
In conjunction with light refraction principle it is recognised that due in the electro-optical deflection period, the modulation voltage makes the electricity
The refractive index of luminescent crystal changes linearly at any time, so the modulation voltage makes the electric light in the electro-optical deflection period
The refractive index of crystal changes linearly at any time.
In conjunction with reference Fig. 3 (B), Fig. 3 (B) shows modulation voltage and time relationship in scan method embodiment shown in Fig. 1
Figure.In figure, abscissa indicates the time；Ordinate indicates modulation voltage squared magnitude, and figure line 32 indicates 120 institute of the second scanning element
Receive the relationship of modulation voltage and time.
So the modulation voltage is in cyclically-varying, the variation of the modulation voltage as shown in figure line 32 in Fig. 3 (B)
Period is equal with the electro-optical deflection period, i.e., the period of change of the described modulation voltage, electro-optical deflection period and described
Sweep time is equal.
In the present embodiment, second scanning element 120 includes secondary electro-optic crystal, i.e., described first electro-optic crystal 129
For secondary electro-optic crystal.In the electro-optical deflection period, the modulation voltage makes the refractive index of the electro-optic crystal be at any time
Linear change.
According to Kerr effect, the refractive index of first electro-optic crystal 129 and the relationship of the modulation voltage are as follows:
The deflection angle and apply alive relationship that the second of the incident beam 121 deflects are as follows:
Wherein, L indicates that optical path length of the light beam in first electro-optic crystal 129, d indicate first electro-optic crystal
129 thickness, V indicate the voltage being applied on first electro-optic crystal 129.
Therefore, in each period of change, the modulation voltage square changes linearly at any time, i.e., the described modulation electricity
Pressure is linearly related with the square root of time, that is to say, that in the electro-optical deflection period, the modulation voltage square at any time
It changes linearly.
In conjunction with reference Fig. 4, the deflection angle of the first deflection in scan method embodiment shown in Fig. 3, the second deflection are shown
Deflection angle and scanning angle and time relational graph.
Wherein, abscissa indicates the time, and unit is × 10-3s；Ordinate indicates beam deflection angle degree.Figure line 51 indicates the
The deflection angle and the relationship of time of one deflection；Figure line 52 indicates the deflection angle and the relationship of time of the second deflection；Figure line 53
Indicate angle scanning curve synthesized after the first deflection and the second deflection.
As shown in figure 4, by second deflection deflection angle and formed delay angle it is equal in magnitude, deflect it is contrary,
Therefore in single detection process, the second deflection can be realized the compensation to delay angle, so as to make the scanning of synthesized angle
Curve maintains constant (t in such as Fig. 4 within the electro-optical deflection period1And t2Between figure line 53 shown in), that is to say, that formed and swept
It retouches light beam and reflecting between formed echo beam through object to be measured does not have differential seat angle exclusive or angle difference smaller.So based on institute
The scan method for stating scanning means 100 can effectively inhibit the adverse effect of delay angle, can be improved relevant efficiency.
On the other hand, since second deflection is realized based on electrooptic effect, the scan method is to delay angle
The speed of compensation is related to corresponding speed of the electrooptic effect to electric signal, therefore the scan method can break through electric machine frequency pair
The limitation of scan frequency, so the scan method can effectively shorten single under the premise of guaranteeing delay angle compensation effect
The time of detection, scan frequency is effectively improved, is advantageously implemented taking into account for high scan frequency and high relevant efficiency.
1kHz is set by the hunting frequency of the first reflecting surface in first scanning element 110, and (pendulum of galvanometer is set
Dynamic frequency is 1kHz), scanning range is 30 °；By taking the laser radar of 300m ranging as an example, single detection time is 2 μ s, and first sweeps
Retouch delay angle size produced by unit 110 about are as follows: 30 ° × 1kHz × 2 μ s=0.06 °.Therefore second scanning element 120 is only
Need to realize 0.06 ° of angle compensation in 2 μ s, i.e., the described electro-optical deflection period is 2 μ s, frequency are as follows: 1/2 μ s=500kHz.
It should be noted that the scan method is applied in coherent laser radar, the laser radar also be can use
Continuous light is scanned, and above-mentioned angle compensation is carried out within the period detected every time, and the period detected every time is to detect
Repetition rate inverse.
In addition, the laser radar includes: scanning means of the invention the present invention also provides a kind of laser radar.
Specifically, the laser radar includes: scanning means, the scanning means is scanning means of the invention.Therefore,
The specific technical solution of the scanning means refers to the embodiment of aforementioned scanning means.Details are not described herein by the present invention.
In some embodiments of the invention, the laser radar is coherent laser radar, that is to say, that the laser radar is
Laser radar based on coherent detection.The laser radar is based on local oscillator light and reflects between formed echo light through object to be measured
Coherent signal realize scanning probe, there are the advantages such as fine angular resolution, High Range Resolution, strong anti-interference ability.
Since the scanning means of the laser radar is scanning means of the invention；In the entire time range detected every time
Interior, first deflection and second deflection can guarantee the optical path of the received light beam of the scanning means and from the scanning
The optical path of the light beam of unit outgoing remains unchanged, and the scanning means 100 is equivalent to be scanned in a stepping manner.So
It is scanned using the scanning means 100, can effectively inhibit delay angle to the influence of relevant efficiency, be conducive to improve delay
Angle problem is conducive to improve relevant efficiency.
On the other hand, the high-speed response of the variation of electric signal, second deflection angle are changed due to electrooptic effect
The high speed of response can postpone angle compensation by velocity interpolation faster, to be conducive to shorten in the case where guaranteeing that optical path is constant
The time of single detection is conducive to improve scan frequency.
So the laser radar can guarantee delay angle compensation effect, that is, under the premise of maintaining optical path constant, effectively
The time for shortening single detection is conducive to improve scan frequency, is advantageously implemented taking into account for high scan frequency and high relevant efficiency.
Although present disclosure is as above, present invention is not limited to this.Anyone skilled in the art are not departing from this
It in the spirit and scope of invention, can make various changes or modifications, therefore protection scope of the present invention should be with claim institute
Subject to the range of restriction.
Claims (19)
1. a kind of scanning means, comprising:
First scanning element, first scanning element are adapted so that the direction of propagation of incident beam occurs the first deflection and formed out
Irradiating light beam, first scanning element change the deflection angle size of first deflection by way of rotating or swinging；
Its feature is just, further includes:
Second scanning element, second scanning element are located at the light of at least one in the incident beam and the outgoing beam
When Lu Zhong, the incident beam or the outgoing beam transmit second scanning element, second scanning element is based on electricity
Luminous effect makes the direction of propagation of the light beam of transmission that the second deflection occur.
2. scanning means as described in claim 1, which is characterized in that second scanning element includes electro-optic crystal, described
Electro-optic crystal is at least one of linear electrooptic crystal and nonlinear electrooptical crystal.
3. scanning means as claimed in claim 2, which is characterized in that the electro-optic crystal is nonlinear electrooptical crystal；It is described
The order of magnitude of the quadratic electro-optic coefficient of electro-optic crystal is 10-14m2/V2To 10-15m2/V2In range.
4. scanning means as claimed in claim 2, which is characterized in that the electro-optic crystal includes: potassium tantalate-niobate crystal, tantalum niobium
At least one of sour potassium crystalline lithium and potassium tantalate-niobate sodium crystal.
5. scanning means as described in claim 1, which is characterized in that first scanning element is changed by way of swing
The direction of propagation of the outgoing beam, first scanning element include: at least one of galvanometer and pendulum mirror；
First scanning element changes the direction of propagation of the outgoing beam, first scanning element by way of rotation
It include: tilting mirror.
6. scanning means as claimed in claim 5, which is characterized in that first scanning element has puts around the first scan axis
The first dynamic reflecting surface；
Second scanning element includes: the first electro-optic crystal, and second deflection includes the light that the first electro-optic crystal makes transmission
Beam is rotated around the first yawing axis；
First yawing axis is parallel with first scan axis.
7. scanning means as claimed in claim 5, which is characterized in that first scanning element has puts around the first scan axis
The first dynamic reflecting surface and the second reflecting surface swung around the second scan axis, first scan axis and second scan axis
It is not parallel；
The ratio of the hunting frequency of first reflecting surface and the hunting frequency of second reflecting surface is less than or equal to preset value；
Second scanning element includes: the first electro-optic crystal and the second electro-optic crystal set gradually along optical path, and described second
Deflection includes that the first electro-optic crystal rotates the light beam of transmission around the first yawing axis；Second electro-optic crystal makes the light beam of transmission
It is rotated around the second yawing axis；First yawing axis and second yawing axis are not parallel；
First yawing axis is parallel to first scan axis；
Second yawing axis is parallel to second scan axis.
8. scanning means as claimed in claim 5, which is characterized in that first scanning element has puts around the first scan axis
The first dynamic reflecting surface and the second reflecting surface swung around the second scan axis, first scan axis and second scan axis
It is mutually perpendicular to；
The ratio of the hunting frequency of first reflecting surface and the hunting frequency of second reflecting surface is greater than preset value；
Second scanning element includes: the first electro-optic crystal, and second deflection includes the light that the first electro-optic crystal makes transmission
Beam is rotated around the first yawing axis；First yawing axis is parallel to first scan axis.
9. scanning means as described in claim 1, which is characterized in that second scanning element, which has, receives light beam incidence
Input face；Beam orthogonal is projected to the input face.
10. scanning means as described in claim 1, which is characterized in that second scanning element includes electro-optic crystal；It is described
Electro-optic crystal receives modulation voltage to realize second deflection；The modulation voltage is less than 100V.
11. scanning means as described in claim 1, which is characterized in that the outgoing beam is suitable for being formed from the scanning
The scanning light beam of device outgoing, the scanning light beam reflect to form echo beam through target to be detected；
Light beam is collected in the acquired formation of echo beam；
The collection light beam is through first scanning element and second scanning element deflection to form signal beams；
The collection light beam and the incident beam are total to road.
12. the scanning means as described in claim 1~11 any one, which is characterized in that first scanning element passes through
Continuous rotation swings the deflection angle size for changing first deflection.
13. a kind of scan method of scanning means, the scanning means are as described in claim 1, which is characterized in that the scanning
Method includes:
Make the incident beam that the first deflection occur to form outgoing beam using first scanning element；
First scanning element is set to rotate or swing to change the deflection angle size of first deflection；
Modulation voltage is provided to second scanning element, is based on the direction of propagation for the light beam for transmiting second scanning element
Second deflection occurs for electrooptic effect to compensate delay angle.
14. scan method as claimed in claim 13, which is characterized in that the deflection angle of second deflection is in periodically change
Change；The period of change of the second deflection deflection angle is the electro-optical deflection period；
In the electro-optical deflection period, the deflection angle of second deflection is changed linearly.
15. scan method as claimed in claim 13, which is characterized in that the deflection angle of second deflection is in periodically change
Change；The period of change of the second deflection deflection angle is the electro-optical deflection period；
Second scanning element includes electro-optic crystal, and in the electro-optical deflection period, the modulation voltage keeps the electric light brilliant
The refractive index of body changes linearly at any time.
16. scan method as claimed in claim 15, which is characterized in that second scanning element includes that secondary electric light is brilliant
Body；
In the electro-optical deflection period, the modulation voltage square changes linearly at any time.
17. the scan method as described in claim 13~16 any one, which is characterized in that first scanning element occurs
Continuous rotation is swung；
The deflection angle consecutive variations of first deflection.
18. a kind of laser radar characterized by comprising
Scanning means as described in claim 1~12 any one.
19. laser radar as claimed in claim 18, which is characterized in that the laser radar is coherent laser radar.
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| CN110967680A (en) * | 2019-12-18 | 2020-04-07 | 中国科学院半导体研究所 | Composite structure rotating mirror for three-dimensional scanning and laser radar applying same |
| CN111025737A (en) * | 2019-12-23 | 2020-04-17 | 中国兵器装备研究院 | Electric scanning continuous light beam orientation device |
| WO2022088334A1 (en) * | 2020-10-30 | 2022-05-05 | 苏州镭智传感科技有限公司 | Coherent laser radar |
| WO2022141452A1 (en) * | 2020-12-31 | 2022-07-07 | 深圳市大疆创新科技有限公司 | Detection apparatus, unmanned aerial vehicle, and detection apparatus control method and apparatus |
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