High-magnification oblique imaging lens, assembly method and measuring equipment

Abstract

The present invention discloses a high-magnification oblique imaging lens, an assembly method and a measuring device, comprising a first lens component, located at the rear side of the lens object plane, a second lens component, located at the rear side of the second object plane, and the first image plane as the second object plane; the principal plane of the first lens component, the lens object plane and the first image plane intersect on a line, the principal plane of the second lens component, the second object plane and the lens image plane intersect on a line, the principal plane of the first lens component is a plane perpendicular to the optical axis of the first lens component and including the optical center of the first lens component, and the principal plane of the second lens component is a plane perpendicular to the optical axis of the second lens component and including the optical center of the second lens component. The present invention realizes the combination of Sham's laws in spatial structure, breaks through the limitation between the magnification of the lens and the incident angle of the sensor light in principle, and can not only realize a high-magnification oblique imaging lens, but also can be incident on the sensor at a smaller angle, thereby improving the incident angle of the light.

Description

Technical Field

[0001] The invention belongs to the field of optical lenses, and in particular relates to a high-magnification oblique imaging lens, an assembly method and a measuring device. Background Art

[0002] With the vigorous development of machine vision technology, 3D line laser measurement technology has been widely used in the field of industrial inspection. It is based on the principle of triangulation, and uses image sensors to capture the laser line information projected by the laser on the surface of an object, thereby reconstructing the surface contour information of the object. In the image acquisition process, the lens is required to shoot the tilted target object, but the traditional lens is limited by the depth of field and it is difficult to clearly image the tilted object surface in full field, thus affecting the measurement accuracy of the oblique image lens in the field of 3D line laser measurement. By using Schaum's law, the lens is gradually tilted so that the extended surfaces of the three planes, the object plane, the image plane, and the lens plane, intersect in a straight line, so that the entire surface of the object can be clearly imaged.

[0003] Patent document CN112269242B discloses a high-resolution oblique image lens, and proposes an oblique image lens with a maximum magnification of 0.754. Although the angle between the detector plane and the optical axis of this lens reaches 76.23 degrees, the angle between its target plane and the optical axis is 72 degrees, which is easy to form occlusion in actual industrial scenes, reducing its practical value.

[0004] In the actual application of 3D line laser measurement, the demand for high-precision measurement in a small field of view is increasing, and a high-magnification Sham lens is required to match the application scenario. Existing Sham lens patents are often designed for a specific application scenario with a magnification much less than 1; moreover, using only Sham's law, there is a restrictive relationship between the lens magnification and the sensor light incident angle, and the photoelectric efficiency of the sensor decreases significantly as the light incident angle increases.

[0005] Therefore, in order to solve the above problems, the present invention provides a high-magnification oblique imaging lens, an assembly method and a measuring device. Summary of the invention

[0006] The purpose of the present invention is to overcome the above problems existing in the prior art and to provide a high-magnification oblique imaging lens, an assembly method and a measuring device.

[0007] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0008] A high-magnification oblique imaging lens, comprising:

[0009] The first lens component is located at the rear side of the lens object plane; by changing the focal length of the first lens component, the light emitted from the lens object plane is imaged onto the first image plane, so that the angle between the optical axis of the first lens component and the first image plane is adjusted;

[0010] A second lens component is located at the rear side of the second object plane, and is used to increase the angle between the optical axis of the second lens component and the second object plane and / or reduce the angle between the optical axis of the first lens component and the first image plane, converge the light corresponding to the second object plane, and image it onto the lens image plane, so as to form a high-magnification oblique image while reducing the angle of the light emitted by the second lens component incident on the lens image plane;

[0011] Among them, the first image plane serves as the second object plane; the principal plane of the first lens component, the object plane of the lens and the first image plane intersect on a line, the principal plane of the second lens component, the second object plane and the image plane of the lens intersect on a line, the principal plane of the first lens component is a plane perpendicular to the optical axis of the first lens component and containing the optical center of the first lens component, and the principal plane of the second lens component is a plane perpendicular to the optical axis of the second lens component and containing the optical center of the second lens component.

[0012] Further, the first lens component has positive refractive power; and the second lens component has positive refractive power.

[0013] Furthermore, a plurality of third lens components are included between the second lens component and the lens image plane, and each third lens component is used to increase the angle between its optical axis and its corresponding object plane and / or reduce the angle between the optical axis of the previous third lens component or the second lens component and the corresponding image plane, and finally image the image onto the lens image plane.

[0014] Further, a first angle θ1 is formed between the optical axis of the first lens component and the object plane of the lens, a second angle θ2 is formed between the optical axis of the first lens component and the first image plane, a third angle θ3 is formed between the optical axis of the second lens component and the second object plane, and a fourth angle θ4 is formed between the optical axis of the second lens component and the second mirror plane. The central magnification m of the imaging lens satisfies the following relationship: .

[0015] Furthermore, when the first angle θ1=45° and the center magnification m is 1.8:

[0016] θ2=54.66°,θ3=82.99°.

[0017] Furthermore, when the first angle θ1=40° and the center magnification m is 1.5:

[0018] θ2=53.19°,θ3=85.76°.

[0019] Furthermore, when the first angle θ1=40° and the center magnification m is 1.72:

[0020] θ2=73.64°,θ3=87.33°.

[0021] Furthermore, the first lens component and the second lens component are both composed of a plurality of sub-lenses.

[0022] The present invention also provides a method for assembling a high-magnification oblique imaging lens, which is used to assemble the imaging lens, comprising:

[0023] Determine the angle between the optical axis of the first lens component and the object plane of the lens and the central magnification to be achieved;

[0024] Obtaining the angle between the optical axis of the second lens component and the second mirror surface, selecting the angle between the optical axis of the first lens component and the first image plane and the angle between the optical axis of the second lens component and the second object plane;

[0025] The positions and parameters of the first lens component and the second lens component are adjusted to complete the installation of the first lens component and the second lens component.

[0026] The present invention also provides a measuring device, comprising:

[0027] Such as the imaging lens mentioned above;

[0028] The sensor is used to receive the optical signal of the imaging lens.

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention realizes the combination of Scham's laws in a spatial structure by making the principal plane of the first lens component, the object plane of the lens and the first image plane intersect on a line, and the principal plane of the second lens component, the second object plane and the image plane of the lens intersect on a line, and taking the first image plane as the second object plane. In principle, it breaks through the limitation between the magnification of the lens and the incident angle of the sensor light, and can not only realize a high-magnification oblique image lens, but also can be incident on the sensor at a smaller angle, thereby improving the incident angle of the light.

[0031] (2) The present invention provides a variety of implementation methods based on Schaum's law. The intersection lines of the first lens component and the second lens component that satisfy Schaum's law can be on the same side or on different sides, and the central magnification of the entire imaging lens can satisfy the same imaging law, providing more implementation possibilities for actual scene assembly and selection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 This is a schematic diagram of the imaging principle of Sham's law in the present invention;

[0034] Figure 2 It is a schematic diagram of the optical path principle in the present invention;

[0035] Figure 3 It is a schematic diagram of the optical path principle in the present invention;

[0036] Figure 4 This is a schematic diagram of the optical path of Example 1 of the present invention;

[0037] Figure 5 This is a schematic diagram of the optical path of Example 2 of the present invention;

[0038] Figure 6 It is a schematic diagram of the optical path of Example 3 of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] like Figure 1 The figure shows the principle diagram of Schaum's law imaging. When there are angles between the object plane and the image plane and the optical axis, and the extended lines of the object plane, the lens principal plane, and the image plane intersect on a single line, a clear image of the entire inclined plane can be achieved, and the angle α between the object plane and the optical axis, and the angle β between the image plane and the optical axis, satisfy: . Where m is the center magnification of the lens (referred to as "magnification"). Therefore, Schaum's law can achieve clear imaging in the entire tilted field of view. If the angle between the object plane and the optical axis is α=45°, and the center magnification m=-1.8, then the angle between the image plane and the optical axis is β=29°, that is, the center light is incident on the sensor at an angle of 90°-29°=61°.

[0041] To this end, we introduced a second lens component and, through the combined use of Schaam's law, achieved high-magnification oblique imaging while breaking through the limitations of the imaging magnification and the incident angle of the sensor light under the single Schaam's law.

[0042] like Figure 2 As shown, this embodiment first provides a high-magnification oblique imaging lens, including:

[0043] The first lens component U1 is located behind the lens object plane. Figure 2by changing the focal length of the first lens component U1, the light emitted from the lens object plane is imaged to the first image plane, so that the angle between the optical axis of the first lens component U1 and the first image plane is adjusted.

[0044] The second lens component U2 is located at the rear side of the second object plane, and is used to increase the angle between the optical axis of the second lens component U2 and the second object plane and / or reduce the angle between the optical axis of the first lens component U1 and the first image plane, converge the light corresponding to the second object plane, and image it onto the lens image plane, which is Figure 2 The second image plane in the lens is formed so that a high-magnification oblique image is formed while reducing the angle of the light emitted by the second lens component U2 and incident on the lens image plane.

[0045] Among them, the first image plane serves as the second object plane; the principal plane of the first lens component U1, the object plane of the lens and the first image plane intersect on a line, the principal plane of the second lens component U2, the second object plane and the image plane of the lens intersect on a line, the principal plane of the first lens component U1 is a plane perpendicular to the optical axis of the first lens component U1 and containing the optical center of the first lens component U1, and the principal plane of the second lens component U2 is a plane perpendicular to the optical axis of the second lens component U2 and containing the optical center of the second lens component U2.

[0046] Figure 2 Schematic diagram of the optical path principle: a first angle θ1 is formed between the optical axis of the first lens component and the object plane of the lens, a second angle θ2 is formed between the optical axis of the first lens component and the first image plane, a third angle θ3 is formed between the optical axis of the second lens component and the second object plane, and a fourth angle θ4 is formed between the optical axis of the second lens component and the second mirror plane.

[0047] The principal plane of the first lens component U1, the first object plane, and the first image plane intersect on a line, and the first object plane can be clearly imaged on the first image plane. At this time, the first angle θ1 between the optical axis of the first lens component U1 and the lens object plane, and the second angle θ2 between the optical axis of the first lens component U1 and the first image plane satisfy: Wherein, m1 is the central magnification of the first lens component U1.

[0048] The first image plane can also serve as the second object plane relative to the second lens component U2. The principal plane of the second lens component U2, the second object plane and the second image plane intersect on a line, and the second object plane can be clearly imaged on the second image plane. At this time, the third angle θ3 between the optical axis of the second lens component U2 and the second object plane and the fourth angle θ4 between the optical axis of the second lens component U2 and the second mirror plane satisfy: Wherein, m2 is the central magnification of the second lens component U2.

[0049] The central magnification m of the entire imaging lens satisfies the following relationship:

[0050] .

[0051] It can be seen that by selecting appropriate θ2 and θ3, a larger magnification m can be achieved while keeping θ4 large, thus breaking through the limitation between the imaging magnification of the high-power oblique image lens and the incident angle of the sensor light.

[0052] like Figure 3 As shown in FIG. 1 , as another optical path principle diagram of an imaging lens, the intersection line of the first lens component U1 and the second lens component U2 satisfying Scham's law may not be on the same side, but the central magnification m of the entire imaging lens satisfies the following relationship: .

[0053] As a specific embodiment of the present invention, the first lens component U1 has positive refractive power; the second lens component U2 has positive refractive power, so that the first object plane can be imaged on the first image plane and the second object plane can be imaged on the second image plane more clearly.

[0054] The imaging process and principle of the imaging lens of the present invention are as follows:

[0055] The light emitted from the object plane of the lens, i.e. the first object plane, is converged by the first lens component U1 and imaged on the first image plane. At this time, since the principal plane of the first lens component U1, the object plane of the lens and the first image plane intersect on a line, according to Schaum's law, the light emitted from the first object plane can be clearly imaged on the first image plane; the light imaged on the first image plane continues to converge through the second lens component U2 and is imaged on the second image plane, i.e. the image plane of the lens. At this time, the first image plane can also serve as the second object plane relative to the second lens component U2. Since the principal plane of the second lens component U2, the second object plane and the second image plane intersect on a line, again according to Schaum's law, the light after the clear imaging of the first image plane can be clearly imaged on the second image plane again.

[0056] For single lens imaging, due to the limitation of Schaum's law, once the first angle θ1 and the center magnification are determined, in order to comply with Schaum's law, the second angle θ2 is determined accordingly, which makes it impossible to break through the limitation between the magnification and the incident angle of the sensor light in principle. The present invention realizes the combination of two Schaum's laws by combining the first lens component U1 and the second lens component U2. Since the center magnification m of the entire imaging lens is:

[0057] ,Right now .

[0058] Therefore, if the center magnification m and θ1 are confirmed, then in order to adjust and obtain a larger θ4 that meets the requirements, θ3 can be increased, θ2 can be reduced, or θ3 can be increased and θ2 can be reduced at the same time. In this way, the present invention is no longer subject to the limitation between the magnification and the incident angle of the sensor light caused by the single Scham's law in principle, which provides a rich selection space for actual lens design, has a large parameter selection range, and has a wide range of application scenarios.

[0059] Although only the first lens component U1 and the second lens component U2 are described above, they are only used as the minimum combination method for combining Sham's law. In addition, several other third lens components can be added for combination, as shown below:

[0060] A plurality of third lens components are also included between the second lens component U2 and the lens image plane, and each third lens component is used to increase the angle between its optical axis and its corresponding object plane and / or reduce the angle between the optical axis of the previous third lens component or the second lens component U2 and the corresponding image plane, and finally form an image on the lens image plane.

[0061] For example, a third lens component is added between the second lens component U2 and the lens image plane, the second image plane can be used as a third object plane relative to the third lens component, a fifth angle θ5 is formed between the optical axis of the third lens component and the third object plane, and a sixth angle θ6 is formed between the optical axis of the third lens component and the lens image plane, then .

[0062] Wherein, m3 is the central magnification of the third lens component.

[0063] At this time, the central magnification m of the entire imaging lens satisfies the following relationship:

[0064] .

[0065] Then, by selecting appropriate θ2, θ3, θ4, and θ5, a larger magnification m can be achieved while keeping θ6 large, thereby breaking through the limitations of the imaging magnification of the high-power oblique image lens and the incident angle of the sensor light.

[0066] As a specific implementation of the present invention, the first lens component U1 and the second lens component U2 can be used as separate lenses, or can be composed of a number of sub-lenses through a gluing process and / or gap arrangement, and the specific selection can be based on actual scenarios and requirements.

[0067] The present invention is described in detail below with reference to the specific parameters of the three embodiments: Example 1

[0068] Taking the first angle θ1=45° between the optical axis of the first lens component U1 and the object plane of the lens and the overall magnification m=1.8 as an example, if calculated according to the single Scham's law, the angle between the image plane and the optical axis is 29°, that is, the central light is incident on the sensor at an angle of 90°-29°=61°.

[0069] Using the above simultaneous relations, we have: .

[0070] like Figure 4 As shown, taking θ2=54.66°, θ3=82.99°, we can get θ4=72.69°, that is, the central light is incident on the sensor at an angle of 90°-72.69°=17.31°, which greatly improves the incident angle of the light.

[0071] The incident X-field size is 10.5 mm, the image plane X-field size is 18.86 mm, and the lateral magnification is about 1.796, which is consistent with the design value. The specific parameters are shown in Table 1.

[0072] Table 1

[0073] Example 2

[0074] Taking the first angle θ1=40° between the optical axis of the first lens component U1 and the object plane of the lens and the overall magnification m=1.5 as an example, if calculated according to the single Scham's law, the angle between the image plane and the optical axis is 29.2°, that is, the central light is incident on the sensor at an angle of 90°-29.2°=60.8°.

[0075] Using the above simultaneous relations, we have: .

[0076] like Figure 5 As shown, taking θ2=53.19°, θ3=85.76°, we can get θ4=79.96°, that is, the central light is incident on the sensor at an angle of 90°-79.96°=10.04°, which greatly improves the incident angle of the light.

[0077] The incident X-field size is 10.5 mm, the image plane X-field size is 15.74 mm, and the lateral magnification is about 1.499, which is consistent with the design value. The specific parameters are shown in Table 2.

[0078] Table 2

[0079] Example 3

[0080] Taking the first angle θ1=40° between the optical axis of the first lens component U1 and the object plane of the lens and the overall magnification m=1.72 as an example, if calculated according to the single Scham's law, the angle between the image plane and the optical axis is 25°, that is, the central light is incident on the sensor at an angle of 90°-25°=65°.

[0081] Using the above simultaneous relations, we have: .

[0082] like Figure 6 As shown, taking θ2=73.64°, θ3=87.33°, we can get θ4=72°, that is, the central light is incident on the sensor at an angle of 90°-72°=18°, which greatly improves the incident angle of the light.

[0083] The incident X-field size is 10.5 mm, the image plane X-field size is 18.03 mm, and the lateral magnification is about 1.72, which is consistent with the design value. The specific parameters are shown in Table 3.

[0084] Table 3

[0085]

[0086] A second aspect of the present invention further provides a method for assembling a high-magnification oblique imaging lens, which is used to assemble the above imaging lens, comprising:

[0087] Determine the angle between the optical axis of the first lens component U1 and the lens object plane and the center magnification to be achieved;

[0088] Obtain the included angle between the optical axis of the second lens component U2 and the second mirror surface, select the included angle between the optical axis of the first lens component U1 and the first image plane and the included angle between the optical axis of the second lens component U2 and the second object plane;

[0089] The positions and parameters of the first lens component U1 and the second lens component U2 are adjusted to complete the installation of the first lens component U1 and the second lens component U2.

[0090] The third aspect of the present invention also provides a measuring device, comprising:

[0091] Such as the imaging lens mentioned above;

[0092] The sensor is used to receive the optical signal of the imaging lens.

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0094] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A high magnification oblique imaging lens, characterized in that: include: The first lens component is located at the rear side of the lens object plane; by changing the focal length of the first lens component, the light emitted from the lens object plane is imaged onto the first image plane, so that the angle between the optical axis of the first lens component and the first image plane is adjusted; A second lens component is located at the rear side of the second object plane, and is used to increase the angle between the optical axis of the second lens component and the second object plane and / or reduce the angle between the optical axis of the first lens component and the first image plane, converge the light corresponding to the second object plane, and image it onto the lens image plane, so as to form a high-magnification oblique image while reducing the angle of the light emitted by the second lens component incident on the lens image plane; Wherein, the first image plane serves as the second object plane; the principal plane of the first lens component, the object plane of the lens and the first image plane intersect on a line, the principal plane of the second lens component, the second object plane and the image plane of the lens intersect on a line, the principal plane of the first lens component is a plane perpendicular to the optical axis of the first lens component and containing the optical center of the first lens component, and the principal plane of the second lens component is a plane perpendicular to the optical axis of the second lens component and containing the optical center of the second lens component; The lens comprises a lens object plane, a first lens component, a coordinate discontinuity, a second lens component, and a lens image plane, and the distances from the next plane are 40 mm, 10 mm, 12.403 mm, 87.597 mm, and 0 mm, respectively; the inclination angle of the lens object plane is 40°, the focal length of the first lens component is 7.905 mm, the coordinate discontinuity is 0.036 mm eccentric along the Y direction, and is inclined by -13.692° along the X direction, the focal length of the second lens component is 10.928 mm, the lens image plane is 0 mm eccentric along the Y direction, and is inclined by 18° along the X direction; the center magnification m is 1.72, θ2=73.64°, θ3=87.33°, wherein θ2 is the angle between the optical axis of the first lens component and the first image plane, and θ3 is the angle formed between the optical axis of the second lens component and the second object plane.

2. The high-magnification oblique imaging lens according to claim 1, characterized in that: The first lens component has positive refractive power; The second lens component has positive refractive power.

3. The high magnification oblique imaging lens according to claim 1, characterized in that: The first lens component and the second lens component are both composed of a plurality of sub-lenses.

4. A method for assembling a high-magnification oblique imaging lens, characterized in that: Used to assemble the imaging lens according to any one of claims 1 to 3, comprising: Determine the angle between the optical axis of the first lens component and the object plane of the lens and the central magnification to be achieved; Obtaining the angle between the optical axis of the second lens component and the second mirror surface, selecting the angle between the optical axis of the first lens component and the first image plane and the angle between the optical axis of the second lens component and the second object plane; The positions and parameters of the first lens component and the second lens component are adjusted to complete the installation of the first lens component and the second lens component.

5. A measuring device, characterized in that: include: The imaging lens as claimed in any one of claims 1 to 3; The sensor is used to receive the optical signal of the imaging lens.

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