1. Receiving objective, characterized in that the receiving objective (4) comprises: the objective lens comprises an objective lens body (100), wherein the objective lens body (100) comprises a first light incoming surface and a first light outgoing surface which are arranged at intervals along the direction from a light incoming side to a light outgoing side, and the first light incoming surface comprises a first curved surface (110) protruding towards the light incoming side;

a first compensation lens (200) and a second compensation lens (300) are arranged on the first light emitting surface, the first compensation lens (200) comprises a second light incident surface and a second light emitting surface, the second compensation lens (300) comprises a third light incident surface and a third light emitting surface, and the second light incident surface and the third light incident surface are attached to the first light emitting surface;

the second light emitting surface comprises a second curved surface (210) protruding towards the light emitting side, the optical axis of the second curved surface (210) inclines towards the direction of the optical axis of the objective lens body (100) along the direction of the light emitting side, the second curved surface (210) is used for converging first incident light rays irradiated on the first light incident surface, so that at least one part of light spots of emergent light of the first incident light rays fall in the receiving surface (400), and the included angle between the first incident light rays and the optical axis of the objective lens body (100) is within a first angle range;

the third light-emitting surface is a third curved surface (310) which is concave towards the light-incident side, the optical axis of the third curved surface (310) inclines towards the direction of the optical axis of the objective lens body (100) along the direction of the light-incident side, and the third curved surface (310) is used for diverging second incident light irradiated on the first light-incident surface so that at least one part of light spots of emergent light of the second incident light fall in the receiving surface (400); the included angle between the second incident ray and the optical axis of the objective lens body (100) is within a second angle range, and the minimum value of the second angle range is equal to the maximum value of the first angle range;

the receiving surface (400) is perpendicular to the optical axis of the objective body (100) and is positioned on the focus of the light outlet side of the objective body (100).

2. Receiving objective according to claim 1, characterized in that the first compensation lens (200) is a spherical lens; the second compensation lens (300) is a cylindrical lens.

3. Laser rangefinder characterized in that it comprises a receiving objective (4) according to claim 1 or 2.

4. The laser rangefinder according to claim 3, characterized in that it further comprises a laser emission light source (1), a collimator objective (2) and a photo receiver (5), said collimator objective (2) being adapted to receive light emitted by the laser emission light source (1) and to converge it on a measurement target (3);

the receiving objective (4) is used for receiving light reflected by the measuring target (3), and the photoelectric receiver (5) is positioned at a focus of the light outlet side of the objective body (100).

5. Laser range finder according to claim 4, characterized in that the optical axis of the collimator objective (2) and the optical axis of the receiving objective (4) are arranged parallel and spaced apart in a first direction;

the distance between the optical axis of the collimator objective (2) and the optical axis of the receiving objective (4) is 8-16 mm.

6. The laser distance measuring instrument according to claim 5, wherein the second compensating lens (300) is a cylindrical lens, and the distance between the center of the projection of the first compensating lens (200) on the first light emitting surface and the optical axis position of the first light emitting surface is equal to the distance between the center of the projection of the second compensating lens (300) on the first light emitting surface and the optical axis position of the first light emitting surface.

7. The laser distance measuring device according to claim 6, wherein a positioning circle is formed by taking the optical axis position of the first light emitting surface as the center of circle and the distance between the center of the projection of the first compensation lens (200) on the first light emitting surface and the optical axis position of the first light emitting surface as the radius, the center of the projection of the second compensation lens (300) on the first light emitting surface is on the positioning circle, and the size of the projection of the second compensation lens (300) on the first light emitting surface is 3 mm × 2 mm, and the cylindrical direction of the second compensation lens (300) is parallel to the radial direction of the positioning circle.

8. The laser distance meter of claim 3, wherein an angle formed by a connecting line between the center of the projection of the first compensation lens (200) on the first light emitting surface and the optical axis position of the first light emitting surface and a connecting line between the center of the projection of the second compensation lens (300) on the first light emitting surface and the optical axis position of the first light emitting surface is 80-90 °.

9. The laser range finder of claim 3, wherein the focal length of the first curved surface (110) is 40-45 mm, the radius of curvature of the second curved surface (210) is 120-140 mm, and the radius of curvature of the third curved surface (310) is 50-70 mm.

10. The laser range finder of claim 3, wherein the optical axis of the second curved surface (210) and the optical axis of the third curved surface (310) are each spaced from the optical axis of the objective body (100) by a distance of 3 mm to 5 mm.

Background

The laser range finder has wide application in engineering measurement, building measurement, home decoration and the like. Commonly used hand-held laser rangefinders are generally based on the phase measurement principle. The measuring distance of the range finder ranges from several millimeters to hundreds of meters, and the measuring precision reaches more than millimeter level.

A typical optical system of a prior art laser range finder as shown in fig. 1 includes a laser emission light source 1, a collimator objective lens 2, a measurement target 3, a receiving objective lens 4, a photo receiver 5, a light source adjusting circuit 6, a control unit 7, and a measurement result display unit 8.

The collimator objective lens 2 and the receiving objective lens 4 are parallel in optical axis, and the light receiving surface of the light receiver 5 is located at the focal point of the receiving objective lens 4. In addition, there is an internal optical path in the transmitting optical path and the receiving optical path to compensate for drift errors generated in the circuits.

When measuring a distant target 3, the reflected light is incident on the receiving objective 4 as a parallel light and then converged on the focal point of the receiving objective 4, i.e., the receiving surface of the photoelectric receiver 5. When the distance is measured, the reflected light reflected from the target 3 is obliquely incident on the receiving objective 4 in an off-axis light mode and forms an included angle with the optical axis of the receiving objective 4, so that the image is deviated from the focus of the receiving objective 4, and the photoelectric receiver cannot receive the incident reflected measuring light, so that the measurement cannot be carried out, and no data is displayed.

Disclosure of Invention

The invention aims to provide a receiving objective and a laser range finder, and aims to solve the technical problem that the conventional laser range finder cannot measure or cannot measure the distance at a short distance.

In a first aspect, an embodiment of the present invention provides a receiving objective lens, including: the objective lens comprises an objective lens body, a first light incident surface and a first light emergent surface, wherein the first light incident surface and the first light emergent surface are arranged at intervals along the direction from the light incident side to the light emergent side;

the first light emitting surface is provided with a first compensation lens and a second compensation lens, the first compensation lens comprises a second light incident surface and a second light emitting surface, the second compensation lens comprises a third light incident surface and a third light emitting surface, and the second light incident surface and the third light incident surface are both attached to the first light emitting surface;

the second light emitting surface comprises a second curved surface protruding towards the light emitting side, the direction of the light emitting side is along the light incident side, the optical axis of the second curved surface inclines towards the direction of the optical axis of the objective lens body, the second curved surface is used for converging first incident light irradiated on the first light incident surface, so that at least one part of a light spot of emergent light of the first incident light falls in the receiving surface, and the included angle between the first incident light and the optical axis of the objective lens body is within a first angle range;

the third light-emitting surface is a third curved surface which is concave towards the light-in side, the optical axis of the third curved surface inclines towards the direction of the optical axis of the objective lens body along the direction of the light-out side from the light-in side, and the third curved surface is used for diverging the second incident light irradiated on the first light-in surface so that at least one part of the facula of the emergent light of the second incident light falls in the receiving surface; the included angle between the second incident ray and the optical axis of the objective lens body is within a second angle range, and the minimum value of the second angle range is equal to the maximum value of the first angle range;

the receiving surface is perpendicular to the optical axis of the objective lens body and is positioned on the focus of the light emitting side of the objective lens body.

Further, the first compensation lens is a spherical lens; the second compensation lens is a cylindrical lens.

In a second aspect, an embodiment of the present invention provides a laser range finder, where the laser range finder includes the above-mentioned receiving objective lens.

Further, the laser range finder also comprises a laser emission light source, a collimating objective lens and a photoelectric receiver, wherein the collimating objective lens is used for receiving light emitted by the laser emission light source and converging the light on a measurement target;

the receiving objective lens is used for receiving light reflected by a measuring target, and the photoelectric receiver is positioned at a focus of the light outlet side of the objective lens body.

Further, the optical axis of the collimating objective lens and the optical axis of the receiving objective lens are arranged in parallel and at intervals along a first direction;

the distance between the optical axis of the collimator objective and the optical axis of the receiving objective is 8-16 mm.

Further, the second compensation lens is a cylindrical lens, and a distance between a center of a projection of the first compensation lens on the first light emitting surface and an optical axis position of the first light emitting surface is equal to a distance between a center of a projection of the second compensation lens on the first light emitting surface and an optical axis position of the first light emitting surface.

Furthermore, use the optical axis position of first plain noodles as the centre of a circle, with the distance between the optical axis position of the first projection of compensating lens on first plain noodles and first plain noodles forms the location circle as the radius, the center of the projection of second compensating lens on first plain noodles is in on the location circle, just the size of the projection of second compensating lens on first plain noodles is 3 millimeters 2 millimeters, the cylinder direction of second compensating lens with the radial direction of location circle is parallel.

Furthermore, an included angle formed by a connecting line between the center of the projection of the first compensation lens on the first light emitting surface and the optical axis position of the first light emitting surface and a connecting line between the center of the projection of the second compensation lens on the first light emitting surface and the optical axis position of the first light emitting surface is 80-90 degrees.

Further, the focal length of the first curved surface is 40 mm to 45 mm, the radius of curvature of the second curved surface is 120 mm to 140 mm, and the radius of curvature of the third curved surface is 50 mm to 70 mm.

Further, the optical axis of the second curved surface and the optical axis of the third curved surface are respectively 3 mm to 5 mm away from the optical axis of the objective lens body.

The receiving objective lens provided by the embodiment of the invention comprises: the objective lens comprises an objective lens body, a first light incident surface and a first light emergent surface, wherein the first light incident surface and the first light emergent surface are arranged at intervals along the direction from the light incident side to the light emergent side; the first light emitting surface is provided with a first compensation lens and a second compensation lens, the first compensation lens comprises a second light incident surface and a second light emitting surface, the second compensation lens comprises a third light incident surface and a third light emitting surface, and the second light incident surface and the third light incident surface are both attached to the first light emitting surface; the second light emitting surface comprises a second curved surface protruding towards the light emitting side, the direction of the light emitting side is along the light incident side, the optical axis of the second curved surface inclines towards the direction of the optical axis of the objective lens body, the second curved surface is used for converging first incident light irradiated on the first light incident surface, so that at least one part of a light spot of emergent light of the first incident light falls in the receiving surface, and the included angle between the first incident light and the optical axis of the objective lens body is within a first angle range; the third light-emitting surface is a third curved surface which is concave towards the light-in side, the optical axis of the third curved surface inclines towards the direction of the optical axis of the objective lens body along the direction of the light-out side from the light-in side, and the third curved surface is used for diverging the second incident light irradiated on the first light-in surface so that at least one part of the facula of the emergent light of the second incident light falls in the receiving surface; the included angle between the second incident ray and the optical axis of the objective lens body is within a second angle range, and the minimum value of the second angle range is equal to the maximum value of the first angle range; the receiving surface is perpendicular to the optical axis of the objective lens body and is positioned on the focus of the light emitting side of the objective lens body. The transmission principle of the objective lens is as follows: when the target is far away from the receiving objective lens, the reflected measuring light is incident on a first incident surface of the objective lens body in an approximately parallel light mode and can be focused on a photoelectric receiver at a receiving surface; when the distance between the measuring target and the receiving objective lens is shortened, the included angle between the reflected measuring light and the optical axis of the objective lens body is gradually increased to be within the first angle range, the first light incoming surface cannot converge the reflected measuring light to the electric receiver, and the reflected measuring light can be emitted to the photoelectric receiver at the receiving surface under the action of the second curved surface because the optical axis of the second curved surface is inclined to the optical axis of the objective lens body; and when the distance between measurement target and the receiving objective lens continues to shorten, the contained angle of the optical axis of reflection measurement light and objective lens body increases gradually to the second angle within range, relies on the convergence effect to hardly project light to photoelectric receiver, consequently adopts the third curved surface, utilizes the principle that the third curved surface diverges, enlarges the facula to on projecting reflection measurement light to photoelectric receiver. The mode of combining the objective lens body, the first compensation lens and the second compensation lens can enable the reflected light of a short-distance measurement target point to be continuously projected onto the photoelectric receiver, and because the target reflection measurement light at a short distance and a far point is weaker, the energy converged by the second curved surface is stronger, the target reflection measurement light at a short distance and a near point is stronger, but the energy converged by the third curved surface is less, so that the first compensation lens and the second compensation lens are skillfully and accurately arranged in short-distance measurement, the reflected light of the short-distance target can be converged onto the photoelectric receiver continuously and uniformly, and the short-distance measurement quality can be successfully ensured. This is a pioneer without a precedent at present.

The laser range finder provided by the embodiment of the invention comprises the receiving objective lens. Because the laser range finder provided by the embodiment of the invention uses the receiving objective lens, the laser range finder provided by the embodiment of the invention also has the advantage of receiving the objective lens.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic diagram of a prior art laser rangefinder;

FIG. 2 is a schematic diagram of a receiving objective lens provided by an embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2;

FIG. 5 is a schematic diagram of a laser rangefinder provided in an embodiment of the present invention;

FIG. 6 is a schematic diagram of a first compensation lens of a laser range finder provided in accordance with an embodiment of the present invention;

figure 7 is a diagram showing a spot on the photoelectric receiver of figure 6;

FIG. 8 is a schematic diagram of a second compensation lens of a laser range finder provided in accordance with an embodiment of the present invention;

figure 9 is a diagram showing a spot on the photoelectric receiver of figure 8.

Icon: 1-a laser emission light source; 2-a collimating objective lens; 3-measuring the target; 4-a receiving objective lens; 5-a photoelectric receiver; 6-a regulating circuit; 7-a control unit; 8-a display unit;

100-an objective body; 110-a first curved surface; 200-a first compensation lens; 210-a second curved surface; 300-a second compensation lens; 310-a third curved surface; 400-a receiving surface; 510-a second spot; 520-third spot.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The receiving objective lens 4 provided by the embodiment of the invention is used for being installed in a receiving light path of laser distance measurement and is used for converging emitted measuring light onto a receiving surface 400 of the photoelectric receiver 5.

As shown in fig. 2 to 4, the receiving objective 4 includes: the objective lens body 100 comprises a first light incident surface and a first light emergent surface which are arranged along the light incident side towards the light emergent side at intervals, the first light incident surface comprises a first curved surface 110 protruding from the light incident side, the first curved surface 110 has a converging function, and the first curved surface 110 can be of an aspheric surface structure. The first light emitting surface may be a plane perpendicular to the optical axis of the objective lens body 100.

The first light emitting surface is provided with a first compensation lens 200 and a second compensation lens 300, the first compensation lens 200 and the second compensation lens 300 may be both located on the lower half portion of the objective lens body 100, and in the laser range finder, the first compensation lens 200 and the second compensation lens 300 are specifically located on one side close to the emission optical axis and are arranged at intervals in the left-right direction.

The first compensation lens 200 includes a second light incident surface and a second light emitting surface, the second compensation lens 300 includes a third light incident surface and a third light emitting surface, and the second light incident surface and the third light incident surface are both attached to the first light emitting surface. The second light incident surface and the third light incident surface can be connected with the first light emergent surface in a gluing mode. In other embodiments, the objective lens body 100, the first compensation lens 200 and the second compensation lens 300 may be an integral structure, and no seam is formed between the second light incident surface and the first light emitting surface and between the third light incident surface and the first light incident surface.

The second goes out the plain noodles including to the convex second curved surface 210 of light-emitting side, second curved surface 210 optical axis with the optical axis slope of objective body 100, that is to say, along income light side direction light-emitting side direction, the optical axis of second curved surface 210 inclines towards the optical axis direction of objective body 100, second curved surface 210 is used for assembling and shines the first incident ray at first income plain noodles to make the facula at least partly of the emergent light of first incident ray fall on receiving surface 400, first incident ray with the contained angle of objective body 100's optical axis is at first angle within range.

The third light emitting surface is a third curved surface 310 which is concave towards the light incident side, an optical axis of the third curved surface 310 is inclined with respect to an optical axis of the objective lens body 100, that is, the optical axis of the third curved surface 310 is inclined with respect to the optical axis of the objective lens body 100 along the direction of the light incident side, and the third curved surface 310 is used for diverging the second incident light irradiated on the first light incident surface, so that at least a part of a light spot of the emergent light of the second incident light falls in the receiving surface 400; the angle between the second incident light and the optical axis of the objective lens body 100 is within a second angle range.

The minimum value of the second angular range is equal to the maximum value of the first angular range, so that the measurement can be continuously performed, and the generation of a null point (distance which cannot be measured) is avoided.

The receiving surface 400 is perpendicular to the optical axis of the objective lens body 100, is located at a focus of the light exit side of the objective lens body 100, and is used for collecting and receiving the light emitted from the objective lens 4. The photoelectric receiver 5 can only measure the distance if the light emerging from the receiving objective 4 is projected into the receiving surface 400.

As shown in fig. 5, the transmission principle of the objective lens is as follows: when the distance between the target and the receiving objective 4 is relatively far, the reflected measuring light is incident on the first incident surface of the objective body 100 as approximately parallel light, can be focused on the photoelectric receiver 5 at the receiving surface 400, and forms a first light spot; when the distance between the measurement target 3 and the receiving objective 4 is shortened, for example, to 2 meters to 8 meters, the included angle between the reflected measurement light and the optical axis of the objective body 100 gradually increases to the first angle range (a1-a2), the first light incident surface cannot converge the reflected measurement light to the electric receiver, because the optical axis of the second curved surface 210 is inclined to the optical axis of the objective body 100, the reflected measurement light can be emitted to the photoelectric receiver 5 at the receiving surface 400 under the action of the second curved surface 210, and forms a second light spot 510; when the distance between the measurement target 3 and the receiving objective 4 is further shortened, for example, to 0.1 m to 2 m, the included angle between the reflected measurement light and the optical axis of the objective body 100 is gradually increased to a second angle range (a2-A3), and it is difficult to project the light spot to the photoelectric receiver 5 by means of convergence, so that the light spot is enlarged by using the third curved surface 310 and the principle of cylindrical mirror divergence, so that the reflected measurement light is projected to the photoelectric receiver 5, and a third light spot 520 is formed. In this way, the objective lens body 100, the first compensation lens 200 and the second compensation lens 300 are combined, so that the reflected light of the near-distance measurement target 3 can be continuously projected onto the photoelectric receiver 5, and since the target reflected measurement light at a far distance is relatively weak, the second curved surface 210 has relatively strong convergence capability, the target reflected measurement light at a near distance is relatively strong, but the energy converged by the third curved surface 310 is relatively weak, the first compensation lens 200 and the second compensation lens 300 are arranged in the near-distance measurement, so that the reflected light of the near-distance target can be converged onto the photoelectric receiver 5 continuously and uniformly, and the measurement quality of the near-distance measurement can be ensured.

The geometric positions and the curvature radii of the second curved surface 210 of the first compensation lens 200 and the third curved surface 310 of the second compensation lens 300 in the objective lens body 100 are determined by the structure of the distance meter, the parameters of the first curved surface 110, and the distance between the transmitting optical axis and the receiving optical axis, respectively.

The first compensation lens 200 may be a spherical lens. The second compensation lens 300 may be a cylindrical lens, the cross section of the third curved surface 310 on the cylindrical lens is a curve, the measured reflected light passes through the first curved surface 110 and the third curved surface 310 in sequence and then is projected onto the photoelectric receiver 5 as a fan-shaped light beam, and the cylindrical lens has a better energy convergence effect compared with a conventional concave mirror.

As shown in fig. 5 to 9, the laser range finder provided by the embodiment of the present invention includes the above-mentioned receiving objective 4. Since the laser range finder provided by the embodiment of the present invention uses the receiving objective 4, the laser range finder provided by the embodiment of the present invention also has the advantage of the receiving objective 4.

The laser range finder also comprises a laser emission light source 1, a collimating objective 2 and a photoelectric receiver 5. The laser emission light source 1 is used for emitting measurement light, the collimator objective lens 2 is used for receiving the light emitted by the laser emission light source 1 and converging the light on the measurement target 3, the measurement target 3 reflects the measurement light, the receiving objective lens 4 is used for receiving the light reflected by the measurement target 3, and the photoelectric receiver 5 is located at a focus of the light emitting side of the objective lens body 100.

The optical axis of the collimating objective lens 2 and the optical axis of the receiving objective lens 4 are arranged in parallel along a first direction at intervals; the first compensation lens 200 and the second compensation lens 300 may be located at a side of the objective body 100 close to the collimator objective 2.

The distance between the optical axis of the collimator objective 2 and the optical axis of the receiving objective 4 may be 8 mm to 16 mm.

The second compensation lens 300 may be a cylindrical lens, which has a better energy focusing effect than a conventional concave mirror. The distance between the center of the projection of the first compensation lens 200 on the first light emitting surface and the optical axis position of the first light emitting surface and the distance between the center of the projection of the second compensation lens 300 on the first light emitting surface and the optical axis position of the first light emitting surface may be equal.

The optical axis position of the first light-emitting surface is used as the center of a circle, the distance between the center of the projection of the first compensation lens 200 on the first light-emitting surface and the optical axis position of the first light-emitting surface is used as the radius to form a positioning circle, the center of the projection of the second compensation lens 300 on the first light-emitting surface can be on the positioning circle, the projection of the second compensation lens on the first light-emitting surface is rectangular, and the size of the rectangular is 3 mm × 2 mm. The cylindrical direction of the second compensation lens may be parallel to the radial direction of the positioning circle.

An included angle formed by a connecting line between the center of the projection of the first compensation lens 200 on the first light-emitting surface and the optical axis position of the first light-emitting surface and a connecting line between the center of the projection of the second compensation lens 300 on the first light-emitting surface and the optical axis position of the first light-emitting surface is 80-90 degrees.

An included angle between a connection line between the center of the projection of the first compensation lens 200 on the first light emitting surface and the optical axis position of the first light emitting surface and the vertical direction may be 40-45 °. An included angle between a connection line of the center of the projection of the second compensation lens 300 on the first light emitting surface and the optical axis position of the first light emitting surface and the vertical direction may be 40-45 °.

The focal length of the first curved surface 110 is 40 mm to 45 mm. The radius of curvature of the second curved surface 210 is 120 mm to 140 mm. The radius of curvature of the third curved surface 310 is 50 mm to 70 mm.

The distances between the optical axis of the second curved surface 210 and the optical axis of the third curved surface 310 and the optical axis of the objective lens body 100 are 3 mm to 5 mm, respectively.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.