CN212808618U - Device for laser ranging - Google Patents
Device for laser ranging Download PDFInfo
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- CN212808618U CN212808618U CN201922095593.5U CN201922095593U CN212808618U CN 212808618 U CN212808618 U CN 212808618U CN 201922095593 U CN201922095593 U CN 201922095593U CN 212808618 U CN212808618 U CN 212808618U
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Abstract
The utility model relates to an optical instrument technical field discloses a device for laser rangefinder to improve the adaptability to the environment, and improve measurement accuracy. The utility model discloses the device includes: the cascade-connected at least two stages of lens sets, each stage of lens set respectively consists of a polarization grating and an electric control liquid crystal box, each liquid crystal box is respectively provided with two states, the state 1 is used for converting incident light into left-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage, and the state 2 is used for converting the incident light into right-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage; each electric control liquid crystal box is respectively connected with a corresponding liquid crystal box control circuit, and each liquid crystal box control circuit is respectively used for controlling the state switching of the corresponding liquid crystal box according to instructions so as to deflect the light beam finally emitted to the target reflecting surface to different directions in a time-sharing manner.
Description
Technical Field
The utility model relates to an optical instrument technical field especially relates to a device for laser rangefinder.
Background
The laser ranging has been greatly developed since birth due to the advantages of strong anti-interference capability and high precision, and plays a great role in various industries.
Laser ranging is one of the ranging methods in optical ranging, and if light travels in air at a speed c and the time required for one round trip between two points A, B is t, the distance D between two points A, B can be expressed as:
laser rangefinders can be generally divided into two measurement forms, pulse and phase, depending on the measurement time method. The traditional laser range finder is generally single-point measurement, and in the actual operation process, the vertical distance of the surface to be measured is measured, the measuring direction needs to be perpendicular to the surface to be measured, and the minimum value is usually measured by means of equipment auxiliary positioning or multiple times of measurement. Resulting in data that is not accurate enough.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to disclose a device for laser rangefinder to improve the adaptability to the environment, and improve measurement accuracy.
To achieve the above object, the utility model discloses a device for laser rangefinder, include:
the cascade-connected at least two stages of lens sets, each stage of lens set respectively consists of a polarization grating and an electric control liquid crystal box, each liquid crystal box is respectively provided with two states, the state 1 is used for converting incident light into left-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage, and the state 2 is used for converting the incident light into right-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage;
each electric control liquid crystal box is respectively connected with a corresponding liquid crystal box control circuit, and each liquid crystal box control circuit is respectively used for controlling the state switching of the corresponding liquid crystal box according to instructions so as to deflect the light beam finally emitted to the target reflecting surface to different directions in a time-sharing manner.
Preferably, the utility model discloses the device still includes:
a light source for emitting laser light;
the light receiving module is used for receiving the reflected laser;
the timing module is used for recording the laser emission time and the receiving time of the light receiving module;
and the data processing module is used for calculating the time difference between laser emission and laser reception according to the time recorded by the timing module, calculating the distance between the same test point and different reflection points in different deflection directions according to the time difference, and establishing a coordinate system and an equation set to solve the vertical distance between the test point and the laser reflection surface simultaneously according to the distance between the test point and the different reflection points and the diffraction angle of each level of polarization grating.
The utility model discloses following beneficial effect has:
the utility model discloses with cascaded at least two-stage lens group with the light beam time sharing deflection of final outgoing to target plane of reflection on the direction of difference, on this basis, can confirm a plane based on three points to combine the geometric relation of light beam deflection angle and each reflection point and the distance between the test point, realize the utility model discloses the measurement of perpendicular distance between device test point and the target plane of reflection avoids the measuring error that introduces when measuring direction and target plane of reflection out of plumb in traditional laser range finder use, has optimized user experience.
The present invention will be described in further detail below with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. In the drawings:
fig. 1 is a schematic structural diagram of a device for laser ranging according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a coordinate system in a laser distance measurement example disclosed in an embodiment of the present invention.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.
Example one
The embodiment discloses a device for laser rangefinding, includes:
the cascade-connected at least two stages of lens sets respectively comprise a polarization grating and an electric control liquid crystal box, each liquid crystal box is respectively provided with two states, the state 1 is used for converting incident light into left-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage, and the state 2 is used for converting the incident light into right-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage.
The polarization grating of the embodiment realizes light beam diffraction and deflection by controlling the structural periodic arrangement of materials, and is mainly used for deflecting left-handed circularly polarized light into emergent light with +1 diffraction order and deflecting right-handed circularly polarized light into emergent light with-1 diffraction order. If the human definition of positive and negative is reversed, the foregoing description should be replaced with: each polarization grating is used for deflecting left-handed circularly polarized light into emergent light with-1 diffraction order and deflecting right-handed circularly polarized light into emergent light with +1 diffraction order.
In the device of the embodiment, each of the electrically controlled liquid crystal cells is respectively connected with a corresponding liquid crystal cell control circuit, and each of the liquid crystal cell control circuits is respectively used for controlling the state switching of the corresponding liquid crystal cell according to an instruction so as to time-share deflect the light beam finally emitted to the target reflection surface to different directions.
Generally, a liquid crystal cell can change the deflection angle of liquid crystal molecules by applying an external voltage, so as to change the retardation of incident light, and different retardations can determine the polarization state of the final emergent light. For example: when external voltage U1 is applied to the corresponding liquid crystal box by any liquid crystal box control circuit, the liquid crystal box is used for deflecting incident light into left-handed circular polarized light; when the liquid crystal box control circuit applies an external voltage U2 to the liquid crystal box, the liquid crystal box is used for deflecting incident light into right-handed circular polarization; the values of the external voltages U1 and U2 respectively corresponding to the liquid crystal cells in each stage of the lens group are independent from each other. In other words, the liquid crystal cells of each stage of lens sets can be manually calibrated for two voltages to be switched in advance according to the state of the received incident light.
Preferably, in this embodiment, each electrically controlled liquid crystal cell may be encoded and then centrally controlled by a single chip or a central processing unit with similar functions. Therefore, on one hand, the synchronous control of the states of all liquid crystal boxes can be realized; in addition, in the subsequent process of calculating the vertical distance, the evolution of the geometric relationship of the light beam deflection angle in the cascade lens group can be accurately defined conveniently according to a series of unified control instructions for controlling the states of the liquid crystal boxes corresponding to the light beams.
Further, the device for laser ranging of the present embodiment further includes:
a light source for emitting laser light.
And the light receiving module is used for receiving the reflected laser.
And the timing module is used for recording the laser emission time and the receiving time of the light receiving module.
And the data processing module is used for calculating the time difference between laser emission and laser reception according to the time recorded by the timing module, calculating the distance between the same test point and different reflection points in different deflection directions according to the time difference, and then establishing a coordinate system and an equation set according to the distance between the test point and the different reflection points and combining the diffraction angles of all levels of polarization gratings to simultaneously solve the vertical distance between the test point and the laser reflection plane.
Preferably, the light received by the light receiving module of this embodiment is the light returned from the original path of the emitted laser light; the lens group closest to the laser light source is a first-stage lens group, and a polaroid used for ensuring the consistent polarization state of emergent laser and incident laser is further arranged behind the last-stage lens group.
Preferably, the number of the cascaded lens groups of the present embodiment is two, and the grid lines of the polarization gratings of the first lens group and the polarization gratings of the second lens group are perpendicular to each other, so that a rectangular coordinate system can be conveniently established.
As shown in fig. 1, the liquid crystal cell and the polarization grating in the first-stage lens group are respectively denoted as a first liquid crystal cell 1 and a first polarization grating 2, and the liquid crystal cell and the polarization grating in the second-stage lens group are respectively denoted as a second liquid crystal cell 3 and a second polarization grating 4; and a polarizing plate 5 is also arranged between the second polarization grating 4 and the target reflection plane. Generally, a beam of linearly polarized light can obtain ± 1 st order diffracted light through a polarization grating, and the embodiment can realize the regulation and control of energy distribution of ± 1 st order under the action of the liquid crystal box. Therefore, the light beams can be deflected in 4 different directions in a time-sharing manner by connecting two polarization gratings with mutually vertical grid line directions in series and combining the state switching of the liquid crystal box.
As shown in fig. 2, assume that: the diffraction angle of the polarization grating in the first lens group is theta, and the diffraction angle of the polarization grating in the second lens group is theta
And the laser emergent point in front of the first lens group is taken as the original point O where the test point is located, the reflection points on the plane to be tested are respectively A, B, C, D, the angle of two times theta is equal to the angle of AOB, and the angle of two times theta is equal to the angle of AOB
Is equal to the angle of the AOC, and a spatial rectangular coordinate system is established for the y-axis with one direction OA of the beam deflection. The distances from the test point O to the point A, B, C, D on the plane to be tested can be calculated as r1、r2、r3、r4From the geometrical relationship, the coordinates of the point A, B, C, D are (0, r)1，0)、(r2sin2θ，r2cos2θ，0)、(0，
)、
Setting the normal vector of the plane to be measured as
The method can be obtained by any three points according to the following relation:
and then the calculation formula for obtaining the vertical distance d from the test point O to the surface to be tested is as follows:
in summary, the device for laser ranging disclosed in this embodiment uses at least two cascaded lens sets to deflect the light beam finally emitted to the target reflecting surface to different directions in a time-sharing manner, on this basis, a plane can be determined based on three points, and in combination with the geometric relationship of the light beam deflection angle and the distance between each reflection point and the test point, the measurement of the vertical distance between the test point and the target reflecting surface is realized, the measurement error caused when the measurement direction is not perpendicular to the target reflecting surface in the use process of the conventional laser ranging apparatus is avoided, and the user experience is optimized.
Furthermore, the distance measuring device of the present embodiment is provided with a single-point mode switch, so that a user can calculate the distance between the test point and the reflection point in a manner similar to that of a conventional single-point mode light beam or roughly estimate the vertical distance measurement between the test point and the plane where the reflection point is located by combining the corresponding deflection angle in the distance measuring application such as a local narrow space. As a modification, when the vertical distance between the test point and the target reflection surface is measured, the measurement may be performed based on a mode in which the minimum value or the average value is calculated separately from the plural beams.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. An apparatus for laser ranging, comprising:
the cascade connection at least two stages of lens groups, each stage of lens group is respectively composed of a polarization grating and an electric control liquid crystal box, each electric control liquid crystal box adopts a liquid crystal box which is respectively provided with two states, wherein the state 1 is used for converting incident light into left-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage, and the state 2 is used for converting the incident light into right-handed circularly polarized light and then providing the converted light to the polarization grating of the same stage;
each electric control liquid crystal box is respectively connected with a corresponding liquid crystal box control circuit, and each liquid crystal box control circuit is respectively used for controlling the state switching of the corresponding liquid crystal box according to instructions so as to deflect the light beam finally emitted to the target reflecting surface to different directions in a time-sharing manner.
2. The device of claim 1, further comprising a light receiving module, wherein the light received by the light receiving module is returned by the emitted laser light; the lens group closest to the laser light source is a first-stage lens group, and a polaroid used for ensuring the consistent polarization state of emergent laser and incident laser is further arranged behind the last-stage lens group.
3. The device as claimed in claim 1 or 2, wherein the number of the cascaded lens groups is two, and the polarization grating of the first lens group and the polarization grating of the second lens group are perpendicular to each other.
4. The apparatus of claim 3 wherein each of said polarization gratings is configured to deflect left-circularly polarized light into outgoing light of +1 diffraction order and right-circularly polarized light into outgoing light of-1 diffraction order.
5. The apparatus of claim 3 wherein each of said polarization gratings is configured to deflect left-circularly polarized light into outgoing light of-1 diffraction order and right-circularly polarized light into outgoing light of +1 diffraction order, respectively.
6. The device according to claim 3, wherein any of the liquid crystal cell control circuits is adapted to deflect incident light into a left-handed circular polarization when an external voltage U1 is applied to the corresponding liquid crystal cell; when the liquid crystal box control circuit applies an external voltage U2 to the liquid crystal box, the liquid crystal box is used for deflecting incident light into right-handed circular polarization;
the values of the external voltages U1 and U2 respectively corresponding to the liquid crystal cells in each stage of the lens group are independent from each other.
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| CN201922095593.5U CN212808618U (en) | 2019-11-28 | 2019-11-28 | Device for laser ranging |
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| CN201922095593.5U CN212808618U (en) | 2019-11-28 | 2019-11-28 | Device for laser ranging |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111308483A (en) * | 2019-11-28 | 2020-06-19 | 深圳市麓邦技术有限公司 | Laser ranging method and device for laser ranging |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111308483A (en) * | 2019-11-28 | 2020-06-19 | 深圳市麓邦技术有限公司 | Laser ranging method and device for laser ranging |
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