Single-source coaxial multi-directional laser ranging device and ranging method

Abstract

The present invention discloses a single-source coaxial multi-directional laser ranging device and ranging method, the device comprises a point laser light source, a plurality of cascaded main axis spectroscopes and a plurality of optical path changing ranging units, the point laser light source is fixedly arranged on the main axis and emits a laser beam along the main axis; the laser beam emitted by the main axis of the point laser light source is divided into a first beam and a second beam by each cascaded main axis spectroscope, the first beam is an incident beam of the next level parallel to the main axis, the second beam is a reflected beam of the current level perpendicular to the main axis, the second beam enters the corresponding optical path changing ranging unit and measures the distance of the target ranging position in the corresponding direction through the optical path changing ranging unit. The present invention adopts a single light source to form a main axis coaxial laser, forms multi-level multiplexing through cascaded main axis spectroscopes and can be rotated through the angle of the cascaded main axis spectroscope to achieve ranging of targets in any direction; the use of a single light source saves energy loss, and coaxial measurement improves measurement efficiency and accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of laser distance measurement, and in particular relates to a multi-directional laser distance measurement device. Background Art

[0002] Laser interferometer is a universal length measurement that uses the Michelson interferometer system to measure displacement with the laser wavelength as the known length. Laser has the advantages of high intensity, high directionality, spatial coherence, narrow bandwidth and high monochromaticity. At present, the interferometer commonly used to measure length is mainly based on the Michelson interferometer, and uses a frequency-stabilized helium-neon laser as the light source to form a measurement system with interference effect. Laser interferometer can be used with various refractors, reflectors, etc. to measure linear position, speed, angle, flatness, straightness, parallelism and verticality, and can be used as a calibration for precision machine tools or measuring instruments. Laser interferometers can be composed of laser light sources, spectroscopes, filters, reflectors and detection equipment, and have been widely used in scientific research and industry for precision distance measurement.

[0003] Beam splitter, also known as beam splitter, is a kind of coated glass. One or more layers of thin film are coated on the surface of optical glass. When a beam of light is projected onto the coated glass, it is divided into two or more beams through reflection and refraction. Beam splitters have been widely used in general scientific research and industrial fields. Generally, a 45° semi-reflective and semi-transparent beam splitter can be used to split a laser beam into two laser beams propagating in perpendicular orthogonal directions.

[0004] Corner cube reflectors, also called retroreflectors, are insensitive to the incident angle of the incident light. Within a certain range of incident angles, the outgoing light or image will be reflected 180°. The incident light and the outgoing light will not overlap. After the reflected light passes through the corner cube prism, its polarization state will change. It is an ideal reflective optical element.

[0005] In general, traditional laser interferometers measure single distances in a fixed direction. In general, current laser interferometers cannot meet the requirements of simultaneous multi-directional distance measurement with a single coaxial laser light source in the same coordinate system. Summary of the invention

[0006] In order to solve the above problems in the prior art, that is, the prior art cannot realize multi-directional simultaneous ranging of a single coaxial laser light source in the same coordinate system, the present invention provides a single-light source coaxial multi-directional laser ranging device to solve the above problems.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: the present invention provides a single-source coaxial multi-directional laser ranging device, comprising a point laser light source, a plurality of cascaded main axis beam splitters and a plurality of optical path changing ranging units, wherein the point laser light source is fixedly arranged on the main axis and emits a laser beam along the main axis;

[0008] The cascaded spindle beam splitters are located downstream of the point laser light source and are spaced apart along the spindle;

[0009] The laser beam emitted by the main axis of the point laser light source is divided into two beams by each of the cascade main axis beam splitters, and they are defined as a first beam and a second beam, respectively. The first beam is an incident beam of the next stage parallel to the main axis, and the second beam is a reflected beam of the current stage perpendicular to the main axis, and the second beam points to the target ranging position;

[0010] The optical path changing distance measuring unit is located downstream of the corresponding cascade spindle beam splitter in the direction of the second light beam;

[0011] The first light beam continues to enter the next stage cascade main axis beam splitter, and the second light beam enters the corresponding optical path changing distance measuring unit and measures the distance of the target distance measuring position in the corresponding direction through the optical path changing distance measuring unit.

[0012] Furthermore, the cascaded spindle beam splitter is a 45° rotatable beam splitter, and each level of the beam splitter generates a reflected beam of that level and an incident beam of the next level. The reflected beam and the incident beam are perpendicular and orthogonal, and the direction of the reflected beam can be rotated together according to the placement direction of the cascaded spindle beam splitter.

[0013] Furthermore, each of the optical path changing distance measuring units comprises a one-way filter, a distance measuring spectroscope, a target corner reflector, an interference corner reflector and an interference fringe detector, and the one-way filter and the interference fringe detector constitute a connecting device.

[0014] Furthermore, the one-way filter is a one-way pass filter through which the second light beam can pass but cannot pass in the reverse direction.

[0015] Furthermore, the ranging beam splitter is a semi-reflective and semi-transmissive 45° beam splitter, and the main axis reflected light of this level is divided into ranging transmitted light and interference reflected light by the ranging beam splitter, and the ranging transmitted light and the interference reflected light are vertically orthogonal.

[0016] Furthermore, the target corner reflector and the interference corner reflector are both corner reflectors, the corner reflector returns the laser in the opposite direction at 180°, the target corner reflector reflects the ranging transmitted light, and the interference corner reflector reflects the interference reflected light.

[0017] Furthermore, the interference fringe detector is a laser interference fringe detector. The ranging reflected light and the interference reflected light are superimposed on each other by the interference fringe detector to form interference fringes. The interference fringe detector accurately measures the displacement distance through the interference fringes, and obtains the relative distance after continuously superimposing and recording the displacement.

[0018] Furthermore, the positions of the cascaded spindle beam splitter, the one-way filter, the ranging beam splitter, the interference corner reflector and the interference fringe detector at the same level are relatively fixed, and the position between the target corner reflector and the ranging beam splitter is adjustable.

[0019] The present invention also provides a distance measurement method using the single-source coaxial multi-directional laser distance measurement device, comprising: A: a laser light beam emitted by a main axis of a point laser light source passes through each of the cascade main axis beam splitters in sequence, and is divided into two light beams after passing through each of the cascade main axis beam splitters, and the first light beam continues to enter the next cascade main axis beam splitter along the main axis;

[0020] B: The second light beam is directed to the distance measurement target position, enters the optical path change distance measurement unit composed of a one-way filter, a distance measurement beam splitter, a target corner reflector, an interference corner reflector and an interference fringe detector, and completes the accurate measurement of the relative distance on the interference fringe detector;

[0021] C: At the same time, the placement direction of the next-stage cascade spindle beam splitter is adjusted, and the second light beam emitted by the previous-stage cascade spindle beam splitter repeats the process of B after entering the next-stage cascade spindle beam splitter to complete the precise measurement of the relative distance in another direction.

[0022] Specifically, B is as follows: wherein, the second light beam is transmitted through a one-way filter, and is divided into ranging transmission light and interference reflection light after passing through a ranging beam splitter. The ranging transmission light becomes ranging reflection light after passing through a target corner cube reflector, and the interference reflection light is returned in the opposite direction after passing through an interference corner cube reflector. The ranging reflection light and the interference reflection light are superimposed at the ranging beam splitter, synthesized into interference laser and emitted along the reverse direction of the second light beam to the interference fringe detector, which accurately measures the interference fringes and calculates the relative displacement distance through the formation relationship of the interference fringes.

[0023] The beneficial effects of the present invention are:

[0024] The present invention adopts a single light source to form a main axis coaxial laser, forms multi-level multiplexing through cascaded main axis beam splitters, and can rotate through the angle of the cascaded main axis beam splitters to achieve ranging of targets in any direction;

[0025] The use of a single light source can save energy loss. Secondly, compared with the method of using multiple light sources to achieve multi-directional ranging, this device does not need to adjust the main light source multiple times, so it can ensure coaxial measurement and improve measurement efficiency and accuracy. In addition, multi-level multiplexing and flexible setting in any direction expand the application range of this device.

[0026] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the present invention;

[0028] The parts in the accompanying drawings are marked as follows:

[0029] Point laser light source 1, cascade spindle beam splitter 2, one-way filter 3, ranging beam splitter 4, target corner reflector 5, interference corner reflector 6 and interference fringe detector 7. DETAILED DESCRIPTION

[0030] The following is a specific embodiment of the present invention, and those skilled in the art can easily understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented in other different ways, that is, different modifications and changes can be made without departing from the scope disclosed by the present invention.

[0031] Example: Figure 1 As shown, a single-source coaxial multi-directional laser ranging device comprises a point laser light source 1, a plurality of cascaded main axis beam splitters 2 and a plurality of optical path changing ranging units, wherein the point laser light source is fixedly arranged on the main axis and emits a laser beam along the main axis;

[0032] The laser beam emitted by the main axis of the point laser light source is divided into two beams by each of the cascade main axis beam splitters, and they are defined as a first beam and a second beam, respectively. The first beam is an incident beam of the next stage parallel to the main axis, and the second beam is a reflected beam of the current stage perpendicular to the main axis, and the second beam points to the target ranging position;

[0033] The optical path changing distance measuring unit is located downstream of the corresponding cascade spindle beam splitter in the direction of the second light beam;

[0034] The first light beam continues to enter the next stage cascade main axis beam splitter, and the second light beam enters the corresponding optical path changing distance measuring unit and measures the distance of the target distance measuring position in the corresponding direction through the optical path changing distance measuring unit.

[0035] The cascaded spindle beam splitter is a 45° rotatable beam splitter. Each level of the beam splitter generates a reflected beam of that level and an incident beam of the next level. The reflected beam and the incident beam are perpendicular and orthogonal. The direction of the reflected beam can rotate together according to the placement direction of the cascaded spindle beam splitter.

[0036] For example, in this embodiment, the placement directions (or placement angles) of the first two cascaded spindle beam splitters are different.

[0037] The cascaded spindle beam splitter can adjust the proportion of the transmitted light beam (ie, the first light beam) and the reflected light beam (ie, the second light beam) by selecting the model.

[0038] In this embodiment, each of the optical path changing distance measuring units comprises a one-way filter 3, a distance measuring beam splitter 4, a target corner reflector 5, an interference corner reflector 6 and an interference fringe detector 7, and the one-way filter and the interference fringe detector constitute a connecting device.

[0039] In this embodiment, the one-way filter is a one-way pass filter that allows the second light beam to pass through but prevents the second light beam from passing through in the opposite direction.

[0040] In this embodiment, the ranging beam splitter is a semi-reflective and semi-transmissive 45° beam splitter, and the main axis reflected light of this level is divided into ranging transmitted light and interference reflected light by the ranging beam splitter, and the ranging transmitted light and the interference reflected light are vertically orthogonal.

[0041] In this embodiment, the target corner reflector and the interference corner reflector are both corner reflectors. The corner reflector returns the laser in the opposite direction at 180°. The target corner reflector reflects the ranging transmitted light, and the interference corner reflector reflects the interference reflected light.

[0042] In this embodiment, the interference fringe detector is a laser interference fringe detector. The ranging reflected light and the interference reflected light are superimposed on each other by the interference fringe detector to form interference fringes. The interference fringe detector accurately measures the displacement distance through the interference fringes, and obtains the relative distance after continuously superimposing and recording the displacement.

[0043] In this embodiment, the positions of the cascaded spindle beam splitter, the one-way filter, the ranging beam splitter, the interference corner reflector and the interference fringe detector at the same level are relatively fixed, and the position between the target corner reflector and the ranging beam splitter is adjustable.

[0044] A distance measurement method using the single-source coaxial multi-directional laser distance measurement device comprises:

[0045] A: The laser beam emitted by the main axis of the point laser light source passes through each of the cascade main axis beam splitters in sequence, and is divided into two beams after passing through each of the cascade main axis beam splitters. The first beam continues along the main axis to enter the next cascade main axis beam splitter;

[0046] B: The second light beam is directed to the distance measurement target position, enters the optical path change distance measurement unit composed of a one-way filter, a distance measurement beam splitter, a target corner reflector, an interference corner reflector and an interference fringe detector, and completes the accurate measurement of the relative distance on the interference fringe detector;

[0047] C: At the same time, the placement direction of the next-stage cascade spindle beam splitter is adjusted, and the second light beam emitted by the previous-stage cascade spindle beam splitter repeats the process of B after entering the next-stage cascade spindle beam splitter to complete the precise measurement of the relative distance in another direction.

[0048] The number of distance measuring units can be changed according to the set cascade spindle beam splitters and the corresponding optical paths, and the placement direction of each cascade spindle beam splitter can be adjusted to achieve multi-directional target distance measurement.

[0049] For example, in this embodiment, it is assumed that two cascaded main axis beam splitters and two optical path changing distance measuring units are provided. By adjusting the placement direction of each cascaded main axis beam splitter, the corresponding second light beam can be irradiated onto the corresponding target to be measured after being adjusted by the optical path changing distance measuring unit. In this way, the laser distance measuring device can achieve distance measurement of the target to be measured in multiple directions under the condition of one main light source, such as Figure 1 As shown, the placement angles of the first cascade spindle beam splitter and the second cascade spindle beam splitter are different.

[0050] B is specifically: wherein, the second light beam is transmitted through a one-way filter, and is divided into ranging transmission light and interference reflection light after passing through a ranging beam splitter. The ranging transmission light becomes ranging reflection light after passing through a target corner cube reflector, and the interference reflection light returns in the opposite direction after passing through an interference corner cube reflector. The ranging reflection light and the interference reflection light are superimposed at the ranging beam splitter, synthesized into interference laser and emitted along the reverse direction of the second light beam to the interference fringe detector, which accurately measures the interference fringes and calculates the relative displacement distance through the formation relationship of the interference fringes.

[0051] The present invention adopts a single light source to form a main axis coaxial laser, forms multi-level multiplexing through cascaded main axis beam splitters, and can rotate through the angle of the cascaded main axis beam splitters to achieve ranging of targets in any direction;

[0052] The use of a single light source can save energy loss. Secondly, compared with the method of using multiple light sources to achieve multi-directional ranging, this device does not need to adjust the main light source multiple times, so it can ensure coaxial measurement and improve measurement efficiency and accuracy. In addition, multi-level multiplexing and flexible setting in any direction expand the application range of this device.

[0053] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure made using the contents of the present invention's specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A single-source coaxial multi-directional laser ranging device, characterized in that: It includes a point laser light source, a plurality of cascaded main axis beam splitters and a plurality of optical path changing distance measuring units, wherein the point laser light source is fixedly arranged on the main axis and emits a laser light beam along the main axis; The cascaded spindle beam splitters are located downstream of the point laser light source and are spaced apart along the spindle; The laser beam emitted by the main axis of the point laser light source is divided into two beams by each of the cascade main axis beam splitters, and they are defined as a first beam and a second beam, respectively. The first beam is an incident beam of the next stage parallel to the main axis, and the second beam is a reflected beam of the current stage perpendicular to the main axis, and the second beam points to the target ranging position; The optical path changing distance measuring unit is located in the direction of the second light beam and downstream of the corresponding cascade spindle beam splitter; The first light beam continues to enter the next stage cascade main axis beam splitter, and the second light beam enters the corresponding optical path change distance measuring unit and measures the distance of the target distance measuring position in the corresponding direction through the optical path change distance measuring unit; the cascade main axis beam splitter is a beam splitter that can rotate 45 degrees in direction, and each stage of the beam splitter generates a reflected light beam of the stage and an incident light beam of the next stage, and the reflected light beam is perpendicular to the incident light beam, and the direction of the reflected light beam can be rotated together according to the placement direction of the cascade main axis beam splitter; Each of the optical path changing distance measuring units comprises a one-way filter, a distance measuring spectroscope, a target corner cube reflector, an interference corner cube reflector and an interference fringe detector, and the one-way filter and the interference fringe detector constitute a connecting device.

2. The single-source coaxial multi-directional laser ranging device according to claim 1, characterized in that: The one-way filter is a one-way pass filter through which the second light beam can pass but cannot pass in the reverse direction.

3. The single-source coaxial multi-directional laser ranging device according to claim 1, characterized in that: The distance measuring beam splitter is a semi-reflective and semi-transmissive 45° beam splitter. The reflected light beam is divided into distance measuring transmission light and interference reflected light by the distance measuring beam splitter, and the distance measuring transmission light and the interference reflected light are vertically orthogonal.

4. The single-source coaxial multi-directional laser ranging device according to claim 3, characterized in that: The target corner reflector and the interference corner reflector are both corner reflectors. The target corner reflector returns the laser in a 180° reverse direction. The target corner reflector reflects the ranging transmitted light, and the interference corner reflector reflects the interference reflected light.

5. The single-source coaxial multi-directional laser ranging device according to claim 3, characterized in that: The interference fringe detector is a laser interference fringe detector. The ranging reflected light and the interference reflected light are superimposed on each other to form interference fringes through the interference fringe detector. The interference fringe detector accurately measures the displacement distance through the interference fringes, and obtains the relative distance after continuously superimposing and recording the displacement.

6. The single-source coaxial multi-directional laser ranging device according to claim 1, characterized in that: The positions of the cascaded main axis spectroscope, the one-way filter, the ranging spectroscope, the interference corner reflector and the interference fringe detector at the same level are relatively fixed, and the position between the target corner reflector and the ranging spectroscope is adjustable.

7. A distance measurement method using the single-source coaxial multi-directional laser distance measurement device according to claim 1, characterized in that: include: A: The laser beam emitted by the main axis of the point laser light source passes through each of the cascade main axis beam splitters in sequence, and is divided into two beams after passing through each of the cascade main axis beam splitters. The first beam continues along the main axis to enter the next cascade main axis beam splitter; B: The second light beam is directed to the distance measurement target position, enters the optical path change distance measurement unit composed of a one-way filter, a distance measurement beam splitter, a target corner reflector, an interference corner reflector and an interference fringe detector, and completes the accurate measurement of the relative distance on the interference fringe detector; C: At the same time, the placement direction of the next-stage cascade spindle beam splitter is adjusted, and the second light beam emitted by the previous-stage cascade spindle beam splitter repeats the process of B after entering the next-stage cascade spindle beam splitter to complete the precise measurement of the relative distance in another direction.

8. A distance measurement method of the single-source coaxial multi-directional laser distance measurement device according to claim 7, characterized in that: B is specifically: wherein, the second light beam is transmitted through a one-way filter, and is divided into ranging transmission light and interference reflection light after passing through a ranging beam splitter. The ranging transmission light becomes ranging reflection light after passing through a target corner cube reflector, and the interference reflection light returns in the opposite direction after passing through an interference corner cube reflector. The ranging reflection light and the interference reflection light are superimposed at the ranging beam splitter, synthesized into interference laser and emitted along the reverse direction of the second light beam to the interference fringe detector, which accurately measures the interference fringes and calculates the relative displacement distance through the formation relationship of the interference fringes.

Images