High-precision measuring lens and optical system thereof

Abstract

The invention relates to the technical field of machine vision lenses, and discloses a high-precision measuring lens and an optical system thereof. The optical system comprises a front group, a beam splitter prism and a rear group which are sequentially arranged from an object side to an image side, the rear group comprises a first rear group arranged on a reflection path of the beam splitter prism and a second rear group arranged on a transmission path of the beam splitter prism; the amplification factor of a light path structure formed by the front group and the first rear group is X1, and the amplification factor of a light path structure formed by the front group and the second rear group is X2, X1lt; x2. By means of the optical system, two cameras can be supported and connected at the same time for detection, the appearance size or the overall shape of a target object can be amplified and rapidly captured, focusing and high-precision measurement can be carried out on the part with the finer requirement, and the testing efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of machine vision lenses, and in particular to a high-precision measuring lens and an optical system thereof. Background Art

[0002] With the rapid development of the machine vision industry, imagers based on visual inspection can accurately measure and analyze the appearance size, shape and surface features of products. In the field of industrial manufacturing, such as 3C electronics factories and precision hardware processing factories, such imagers are rapidly becoming popular. However, current lenses can only achieve one function, either to detect the size and appearance of workpieces in a larger field of view, or to achieve high-precision measurement of fine workpieces in a very small field of view. It is impossible to obtain both the appearance size of the workpiece and the fine local features of the workpiece.

[0003] Therefore, how to improve the magnification of the measuring lens while being able to magnify and quickly capture the target object's appearance size or overall shape to meet the needs of high-precision measurement of local features has become a technical problem that needs to be urgently solved in this field.

[0004] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0005] The object of the present invention is to provide a high-precision measuring lens and an optical system thereof, so as to solve or at least partially solve the technical problems existing in the prior art.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an optical system of a high-precision measurement lens, comprising a front group, a beam splitter prism and a rear group arranged in sequence from the object side to the image side; the rear group comprises a first rear group arranged on the reflection path of the beam splitter prism, and a second rear group arranged on the transmission path of the beam splitter prism;

[0008] The front group includes a first lens having positive power, a second lens having negative power, a third lens having positive power, a fourth lens having positive power, a fifth lens having positive power, and a sixth lens having negative power;

[0009] The first rear lens group includes a first aperture stop, a seventh lens having negative power, an eighth lens having positive power, a ninth lens having positive power, and a tenth lens having positive power; wherein the first aperture stop is located at a common focus of the front lens group and the first rear lens group, forming a double telecentric structure;

[0010] The second rear group includes a second aperture stop, an eleventh lens with a negative focal power, a twelfth lens with a positive focal power, a thirteenth lens with a positive focal power, and a fourteenth lens with a positive focal power; the second aperture stop is located at the common focal point of the front group and the second rear group, forming a double telecentric architecture;

[0011] Among them, the magnification of the optical path structure formed by the front group and the first rear group is X1, and the magnification of the optical path structure formed by the front group and the second rear group is X2, and X1 < X2.

[0012] Optionally, the combined focal length of the front group is f 100 , the combined focal length of the first rear group is f 200 , and the combined focal length of the second rear group is f 300 ;

[0013] f 100 , f 200 , and f 300 respectively satisfy the following relational expressions:

[0014] 0.35 < |f 200 / f 100 | < 0.7; 1.25 < |f 300 / f 100 | < 1.75.

[0015] Optionally, the first lens and the second lens form a cemented lens U1, and the fifth lens and the sixth lens form a cemented lens U2;

[0016] The combined focal length of the front group is f 100 , the focal length of the third lens is f 3 , f 100 and f 3 satisfy the relational expression: 0.3 < |f 100 / f 3 | < 0.9;

[0017] The focal length of the fourth lens is f 4 , f 100 and f 4 satisfy the relational expression: 0.2 < |f 100 / f 4 | < 0.6;

[0018] The focal length of the cemented lens U1 is f U1 , f 100 and f U1 satisfy the relational expression: |f 100 / f U1 | < 0.15;

[0019] The focal length of the cemented lens U2 is f U2 ; f 100 and fU2 Satisfy the relation: 0.45 < |f 100 / f U2 | < 0.85.

[0020] Optionally, the seventh lens and the eighth lens form a cemented lens U3; the eleventh lens and the twelfth lens form a cemented lens U4;

[0021] The combined focal length of the first rear group is f 200 , the focal length of the cemented lens U3 is f U3 , f 200 and f U3 Satisfy the relation: 0.2 < |f 200 / f U3 | < 0.8;

[0022] The focal length of the ninth lens is f 9 , f 200 and f 9 Satisfy the relation: 0.48 < |f 200 / f 9 | < 0.88;

[0023] The focal length of the tenth lens is f 10 , f 200 and f 10 Satisfy the relation: 0.3 < |f 200 / f 10 | < 0.7;

[0024] The combined focal length of the second rear group is f 300 , the focal length of the cemented lens U4 is f U4 , f 300 and f U4 Satisfy the relation: 1.5 < |f 300 / f U4 | < 2.5;

[0025] The focal length of the thirteenth lens is f 13 , f 300 and f 13 Satisfy the relation: 1 < |f 300 / f 13 | < 1.7;

[0026] The focal length of the fourteenth lens is f 14 , f 300 and f 14 Satisfy the relation: 0.2 < |f 300 / f 14 | < 0.8.

[0027] Optionally, both the first lens and the fourth lens are biconvex lenses, the second lens, the fifth lens, and the sixth lens are all meniscus lenses, and the third lens is a plano-convex lens or a meniscus lens.

[0028] Optionally, both the ninth lens and the tenth lens are meniscus lenses;

[0029] The eleventh lens is a biconcave lens, the twelfth lens is a biconvex lens, the thirteenth lens is a meniscus lens, and the fourteenth lens is a meniscus lens or a plano-convex lens.

[0030] Optionally, the beam splitter prism is a semi-transmissive and semi-reflective prism.

[0031] Optionally, the fifth lens, the eighth lens, the ninth lens, the twelfth lens, and the thirteenth lens are all made of crown glass.

[0032] Optionally, the apertures of the first diaphragm and the second diaphragm are both circular holes, and the centers of the two apertures are both on the optical axis of the optical system.

[0033] In a second aspect, the present invention provides a high-precision measurement lens, including the optical system of a high-precision measurement lens as described above.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The optical system of a high-precision measurement lens provided by the present invention has two optical path structures with different magnification ratios, and can simultaneously support connecting two cameras for detection. It can not only magnify and quickly capture the appearance size or overall shape of the target object, but also perform high-precision measurement on more delicate parts, greatly improving the test efficiency.

[0036] The present invention has other characteristics and advantages, which will be obvious from the accompanying drawings incorporated herein and the subsequent specific embodiments, or will be described in detail in the accompanying drawings incorporated herein and the subsequent specific embodiments. These accompanying drawings and specific embodiments are jointly used to explain the specific principles of the present invention. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0038] Figure 1 It is a schematic structural diagram of an optical system of a high-precision measurement lens provided by an embodiment of the present invention.

[0039] Figure 2 It is a schematic structural diagram of the front group of the optical system of a high-precision measurement lens provided by an embodiment of the present invention.

[0040] Figure 3 It is a schematic structural diagram of a rear group of the optical system of a high-precision measurement lens provided by an embodiment of the present invention.

[0041] Figure 4 It is a schematic structural diagram of another rear group of the optical system of a high-precision measurement lens provided by an embodiment of the present invention.

[0042] Figure 5 It is a schematic optical path diagram of the optical system of a high-precision measurement lens provided by an embodiment of the present invention.

[0043] Figure 6 It is an MTF graph of the optical system of a low-magnification measurement lens provided by an embodiment of the present invention.

[0044] Figure 7 It is an MTF graph of the optical system of a high-magnification measurement lens provided by an embodiment of the present invention.

[0045] Figure 8 It is a schematic distortion diagram of the optical system of a low-magnification measurement lens provided by an embodiment of the present invention.

[0046] Figure 9 It is a schematic distortion diagram of the optical system of a high-magnification measurement lens provided by an embodiment of the present invention. Detailed implementation manners

[0047] To illustrate in detail the possible application scenarios, technical principles, specific implementable solutions, achievable purposes and effects of the present application, the following is described in detail in conjunction with the specific examples listed and with reference to the accompanying drawings. The examples described herein are only used to more clearly illustrate the technical solutions of the present application, so they are only examples and cannot be used to limit the protection scope of the present application.

[0048] Referring to "embodiment" in this article means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing in various positions in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0049] Unless otherwise defined, the technical terms used herein have the same meanings as those commonly understood by those skilled in the technical field to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0050] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that there can be three relationships. For example, A and / or B means: there is A, there is B, and there is both A and B at the same time. In addition, the character " / " herein generally represents an "or" logical relationship between the associated objects before and after.

[0051] In this application, terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary-secondary or order relationship, etc. between these entities or operations.

[0052] Without further limitation, in this application, the expressions such as "including", "comprising", "having" or other similar expressions used in the statement are intended to cover non-exclusive inclusion. These expressions do not exclude that there may be additional elements in the process, method or product including the said elements, so that the process, method or product including a series of elements may not only include those defined elements, but also include other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0053] The same as the understanding in the "Examination Guidelines", in this application, expressions such as "greater than", "less than", "exceeding" are understood not to include the number itself; expressions such as "above", "below", "within" are understood to include the number itself. In addition, in the description of the embodiments of this application, the meaning of "multiple" is two or more (including two), and similar expressions related to "many" are understood in the same way, such as "multiple groups", "multiple times", etc., unless otherwise specifically defined.

[0054] In the description of the embodiments of this application, the spatially related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "perpendicular", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the specific embodiment or the drawings, and is only for the convenience of describing the specific embodiments of this application or for the convenience of readers to understand, rather than indicating or implying that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of this application.

[0055] Unless otherwise clearly specified or limited, in the description of the embodiments of the present application, terms such as "installed", "connected", "joined", "fixed", "set" should be understood in a broad sense. For example, the "connection" may be a fixed connection, a detachable connection, or an integral setting; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium; it may be the communication inside two elements or the interaction relationship between two elements. For those skilled in the art to which the present application pertains, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0056] Embodiment 1:

[0057] Please refer to Figures 1 - 4 , Figure 1 which is a schematic structural diagram of an optical system of a high-precision measurement lens provided by an embodiment of the present invention, Figure 2 which is a schematic structural diagram of the front group 100 of an optical system of a high-precision measurement lens provided by an embodiment of the present invention, Figure 3 which is a schematic structural diagram of a rear group of an optical system of a high-precision measurement lens provided by an embodiment of the present invention, Figure 4 which is a schematic structural diagram of another rear group of an optical system of a high-precision measurement lens provided by an embodiment of the present invention;

[0058] As Figure 1 shown, the optical system includes:

[0059] a front group 100, a beam splitter prism, and a rear group arranged in sequence from the object side to the image side; the rear group includes a first rear group 200 arranged on the reflection path of the beam splitter prism, and a second rear group 300 arranged on the transmission path of the beam splitter prism;

[0060] As Figure 2 shown, the front group 100 includes a first lens 1 with positive optical power, a second lens 2 with negative optical power, a third lens 3 with positive optical power, a fourth lens 4 with positive optical power, a fifth lens 5 with positive optical power, and a sixth lens 6 with negative optical power;

[0061] As Figure 3 shown, the first rear group 200 includes a first aperture stop, a seventh lens 7 with negative optical power, an eighth lens 8 with positive optical power, a ninth lens 9 with positive optical power, and a tenth lens 10 with positive optical power; wherein, the first aperture stop is located at the common focus of the front group 100 and the lens group of the first rear group 200, forming a double telecentric structure;

[0062] As Figure 4As shown, the second rear group 300 includes a second aperture stop, an eleventh lens 11 with a negative focal power, a twelfth lens 12 with a positive focal power, a thirteenth lens 13 with a positive focal power, and a fourteenth lens 14 with a positive focal power; the second aperture stop is located at the common focal point of the front group 100 and the second rear group 300, forming a double telecentric structure;

[0063] The magnification of the optical path structure formed by the front group 100 and the first rear group 200 is X1, and the magnification of the optical path structure formed by the front group 100 and the second rear group 300 is X2; X1 < X2.

[0064] For easy understanding, please continue to refer to Figure 5 , Figure 5 is a schematic diagram of the optical path of an optical system of a high-precision measurement lens provided by an embodiment of the present invention.

[0065] In this embodiment, the first rear group 200 is placed along the reflection light direction of the beam splitter prism (i.e., Figure 1 BS in Figure 3 ), and the rear group 300 is placed along the transmission light direction of the beam splitter prism; the first aperture stop (i.e., Figure 4 S1 in

[0066] Further, the combined focal length of the front group 100 is f 100 , the combined focal length of the first rear group 200 is f 200 , and the combined focal length of the second rear group 300 is f 300 ;

[0067] f 100 , f 200 and f 300 respectively satisfy the following relational expressions:

[0068] 0.35 < |f 200 / f 100 | < 0.7; 1.25 < |f 300 / f 100 | < 1.75.

[0069] Specifically, the first lens 1 and the second lens 2 form a cemented lens U1, and the fifth lens 5 and the sixth lens 6 form a cemented lens U2;

[0070] The combined focal length of the front group 100 is f 100 , the focal length of the third lens 3 is f 3 , f 100 and f 3Satisfy the relational expression: 0.3 < |f 100 / f 3 | < 0.9;

[0071] The focal length of the fourth lens 4 is f 4 , f 100 and f 4 Satisfy the relational expression: 0.2 < |f 100 / f 4 | < 0.6;

[0072] The focal length of the cemented lens U1 is f U1 , f 100 and f U1 Satisfy the relational expression: |f 100 / f U1 | < 0.15;

[0073] The focal length of the cemented lens U2 is f U2 ; f 100 and f U2 Satisfy the relational expression: 0.45 < |f 100 / f U2 | < 0.85.

[0074] In this embodiment, the cemented lens U1 bears a small optical power. The light rays close to the optical axis pass through the cemented lens U1, and its cemented surface can correct the astigmatism and higher-order aberrations of the optical system. Combining with the third lens 3 can effectively correct the chromatic aberration of the system (especially the high-magnification system); the fourth lens 4 has a positive optical power, sharing the refracting light ability of the third lens 3, which is beneficial to compressing the system length. At the same time, the incident angle of the light rays is not too large, reducing off-axis aberrations. A certain interval from the third lens 3 is also beneficial to correcting the system aberrations.

[0075] More specifically, the seventh lens 7 and the eighth lens 8 form the cemented lens U3; the eleventh lens 11 and the twelfth lens 12 form the cemented lens U4;

[0076] The combined focal length of the first rear group 200 is f 200 , the focal length of the cemented lens U3 is f U3 , f 200 and f U3 Satisfy the relational expression: 0.2 < |f 200 / f U3 | < 0.8;

[0077] The focal length of the ninth lens 9 is f 9 , f 200 and f 9 Satisfy the relational expression: 0.48 < |f 200 / f 9 | < 0.88;

[0078] The focal length of the tenth lens 10 is f 10 , f 200 and f 10 satisfy the relationship: 0.3 < |f 200 / f 10 | < 0.7;

[0079] The combined focal length of the second rear group 300 is f 300 , the focal length of the cemented lens U4 is f U4 , f 300 and f U4 satisfy the relationship: 1.5 < |f 300 / f U4 | < 2.5;

[0080] The focal length of the thirteenth lens 13 is f 13 , f 300 and f 13 satisfy the relationship: 1 < |f 300 / f 13 | < 1.7;

[0081] The focal length of the fourteenth lens 14 is f 14 , f 300 and f 14 satisfy the relationship: 0.2 < |f 300 / f 14 | < 0.8.

[0082] In this embodiment, the tenth lens 10 is made of a high refractive index material and has a meniscus structure facing the image plane, which is beneficial to correcting the coma, astigmatism and field curvature of the system.

[0083] More specifically, in this embodiment, the first lens 1 and the fourth lens 4 are both biconvex lenses, the second lens 2, the fifth lens 5 and the sixth lens 6 are all meniscus lenses, and the third lens 3 is a plano-convex lens or a meniscus lens.

[0084] The ninth lens 9 and the tenth lens 10 are both meniscus lenses;

[0085] The eleventh lens 11 is a biconcave lens, the twelfth lens 12 is a biconvex lens, the thirteenth lens 13 is a meniscus lens, and the fourteenth lens 14 is a meniscus lens or a plano-convex lens.

[0086] In this embodiment, each lens in the optical system is a glass spherical lens.

[0087] In this embodiment, the beam splitter prism is a semi-transmissive and semi-reflective prism.

[0088] As a preferred embodiment, in this embodiment, the fifth lens 5, the eighth lens 8, the ninth lens 9, the twelfth lens 12, and the thirteenth lens 13 are all made of crown glass. Using a crown glass lens combination is more conducive to correcting the chromatic aberration of the system.

[0089] As an alternative embodiment, in this embodiment, the apertures of the first diaphragm and the second diaphragm are both circular holes, and the centers of the two apertures are both on the optical axis of the optical system ( Figure 1 The two dotted lines in represent one optical axis respectively, and the centers of the two apertures are respectively on the two optical axes).

[0090] It can be understood that the aperture value of the diaphragm needs to be adjusted correspondingly according to the specific application scenario.

[0091] Exemplarily, to verify the above optical system, a specific test case is also provided in this example, as follows:

[0092] The data of the low-magnification measurement optical system composed of the front group 100 and the first rear group 200 are shown in Table 1 below:

[0093] Table 1

[0094]

[0095]

[0096] It should be noted that in Table 1, the "front surface" corresponds to Figure 2 or Figure 3 the left surface of the corresponding lens or lens group in, and the "rear surface" corresponds to Figure 2 or Figure 3 the right surface of the corresponding lens or lens group in; or it can be understood that: the object side is on the Figure 1 left side, and the image side (or image plane 1) is on the Figure 1 upper side, and the surface closer to the object side is the "front surface", and the surface closer to the image side is the "rear surface".

[0097] The data of the high-magnification measurement optical system composed of the front group 100 and the second rear group 300 are shown in Table 2 below:

[0098] Table 2

[0099]

[0100] It should be noted that in Table 2, the "front surface" corresponds to Figure 1 or Figure 4 the left surface of the corresponding lens or lens group in, and the "rear surface" corresponds to Figure 1 the right surface of the corresponding lens or lens group in; or it can be understood that: the object side is on the Figure 1On the left side, the image side (or image plane 2) is Figure 1 on the right side of Figure 1 . The surface on the side close to the object side is the "front surface", and the surface on the side close to the image side is the "back surface".

[0101] In this embodiment, the combined focal length f of the front group 100 is 100 = 68 mm, the focal length f of the third lens 3 is 3 = 113 mm, the focal length f of the fourth lens 4 is 4 = 169 mm, the focal length f of the cemented lens U1 is U1 = 579 mm, the focal length f of the cemented lens U2 is U2 = -105 mm; the combined focal length f of the first rear group 200 is 200 = 34 mm, the focal length f of the ninth lens 9 is 9 = 50 mm, the focal length f of the tenth lens 10 is 10 = 69 mm, the focal length f of the cemented lens U3 is U3 = -58 mm;

[0102] The combined focal length f of the second rear group 300 is 300 = 103 mm, the focal length f of the thirteenth lens 13 is 13 = 78 mm, the focal length f of the fourteenth lens 14 is 14 = 178 mm, the focal length f of the cemented lens U4 is U4 = -54 mm.

[0103] Substituting the above parameters into the calculation, we get:

[0104] |f 200 / f 100 | = 0.5, |f 300 / f 100 | = 1.515, |f 100 / f 3 | = 0.602, |f 100 / f 4 | = 0.402, |f 100 / f U1 | = 0.117, |f 100 / f U2 | = 0.648, |f 200 / f U3 | = 0.586, |f 200 / f 9 | = 0.68, |f 200 / f 10 | = 0.493, |f 300 / f U4 | = 1.907, |f 300 / f 13 | = 1.321, |f300 / f 14 | = 0.579;

[0105] From the above calculation results, it can be seen that the settings of the above parameters all satisfy the corresponding relational expressions:

[0106] 0.35 < |f 200 / f 100 | < 0.7, 1.25 < |f 300 / f 100 | < 1.75, 0.3 < |f 100 / f 3 | < 0.9, 0.2 < |f 100 / f 4 | < 0.6, |f 100 / f U1 | < 0.15, 0.45 < |f 100 / f U2 | < 0.85, 0.2 < |f 200 / f U3 | < 0.8, 0.48 < |f 200 / f 9 | < 0.88, 0.3 < |f 200 / f 10 | < 0.7, 1.5 < |f 300 / f U4 | < 2.5, 1 < |f 300 / f 13 | < 1.7, 0.2 < |f 300 / f 14 | < 0.8.

[0107] In this embodiment, the optical parameters of the low-magnification measurement lens composed of the front group 100 and the first rear group 200 are shown in Table III below:

[0108] Table III

[0109] Working distance WD 114 mm Magnification ratio 0.5 times Field of view Φ36.8 mm Target surface 1.1 inches MTF30 > 135 lp / mm Telecentricity <0.1°

[0110] Please refer to Figure 6 and Figure 8 , Figure 6 which is the MTF graph of the optical system of a low-magnification measurement lens provided by an embodiment of the present invention, Figure 8 and which is the distortion schematic diagram of the optical system of a low-magnification measurement lens provided by an embodiment of the present invention;

[0111] According to experimental verification, the distortion of the optical system of this low-magnification measurement lens < 0.03%.

[0112] In this embodiment, the optical parameters of the high-magnification measurement lens composed of the front group 100 and the second rear group 300 are shown in Table IV below:

[0113] Table 4

[0114] Working distance WD 114 mm Magnification ratio 1.5 times Field of view Φ12.3 mm Target surface 1.1 inches MTF30 > 100 lp / mm Telecentricity <0.1°

[0115] Please refer to Figure 7 and Figure 9 , Figure 7 which is the MTF graph of the optical system of a high magnification measurement lens provided by an embodiment of the present invention, Figure 9 and which is the schematic diagram of the distortion of the optical system of a high magnification measurement lens provided by an embodiment of the present invention;

[0116] According to experimental verification, the distortion of the optical system of this high magnification measurement lens is < 0.001%.

[0117] In summary, through the structural design of the above optical system in this embodiment, there are optical path structures with two different magnification ratios, high and low. Among them, the magnification ratio of the high magnification optical path structure can reach 1.5 times; it can support connecting two cameras for detection at the same time. The appearance size or overall shape of the target object can be magnified and quickly captured through the low magnification optical path structure, and for more delicate local measurements, switch to the high magnification optical path structure for high-precision measurement, which can greatly improve the test efficiency.

[0118] Embodiment 2:

[0119] This embodiment provides a high-precision measurement lens, including the optical system of a high-precision measurement lens as described in Embodiment 1.

[0120] Based on the relatively detailed description of the optical system in Embodiment 1, it will not be elaborated in this embodiment.

[0121] In summary, through the structural design of the above optical system in this embodiment, a high-precision measurement lens is realized, which has two lens groups with different magnification ratios, high and low. Among them, the magnification ratio of the high magnification lens group can reach 1.5 times; it can be connected to two cameras for detection at the same time. The appearance size or overall shape of the target object can be magnified and quickly captured through the low magnification lens group, and for more delicate local measurements, switch to the high magnification lens group for high-precision measurement, which can greatly improve the test efficiency.

[0122] The above is the case. The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical system for high-precision lens measurement, characterized in that: It comprises a front group (100), a beam splitter prism and a rear group which are arranged in sequence from the object side to the image side; the rear group comprises a first rear group (200) arranged on the reflection path of the beam splitter prism, and a second rear group (300) arranged on the transmission path of the beam splitter prism; The front group (100) includes a first lens (1) having positive power, a second lens (2) having negative power, a third lens (3) having positive power, a fourth lens (4) having positive power, a fifth lens (5) having positive power, and a sixth lens (6) having negative power; The first rear group (200) includes a first aperture stop, a seventh lens (7) with negative focal power, an eighth lens (8) with positive focal power, a ninth lens (9) with positive focal power, and a tenth lens (10) with positive focal power; wherein the first aperture stop is located at the common focus of the front group (100) and the first rear group (200) lens group, forming a double telecentric structure; The second rear group (300) includes a second aperture, an eleventh lens (11) with negative focal power, a twelfth lens (12) with positive focal power, a thirteenth lens (13) with positive focal power, and a fourteenth lens (14) with positive focal power; the second aperture is located at the common focus of the front group (100) and the second rear group (300), forming a double telecentric structure; The magnification of the optical path structure composed of the front group (100) and the first rear group (200) is X1, and the magnification of the optical path structure composed of the front group (100) and the second rear group (300) is X2; X1 <X2。 2. The optical system of a high-precision measurement lens according to claim 1, characterized in that: The combined focal length of the front group (100) is f 100 , the combined focal length of the first rear group (200) is f 200 , the combined focal length of the second rear group (300) is f 300 ; f 100 、f 200 and f 300 They satisfy the following relationships respectively: 0.35<|f 200 / f 100 |<0.7;1.25<|f 300 / f 100 |<1.75。 3. The optical system of a high-precision measurement lens according to claim 2, characterized in that: The first lens (1) and the second lens (2) form a cemented lens U1, and the fifth lens (5) and the sixth lens (6) form a cemented lens U2; The combined focal length of the front group (100) is f 100 , the focal length of the third lens (3) is f3, f 100 and f3 satisfy the relationship: 0.3<|f 100 / f3|<0.9; The focal length of the fourth lens (4) is f4, f 100 and f4 satisfy the relationship: 0.2<|f 100 / f4|<0.6; The focal length of the cemented lens U1 is f U1 , f 100 and f U1 Satisfies the relationship: |f 100 / f U1 |<0.15; The focal length of the doublet lens U2 is f U2 ;f 100 and f U2 Satisfies the relationship: 0.45<|f 100 / f U2 |<0.

85.

4. The optical system of a high-precision measurement lens according to claim 3, characterized in that: The seventh lens (7) and the eighth lens (8) form a cemented lens U3; the eleventh lens (11) and the twelfth lens (12) form a cemented lens U4; The combined focal length of the first rear group (200) is f 200 , the focal length of the cemented lens U3 is f U3 , f 200 and f U3 Satisfies the relationship: 0.2<|f 200 / f U3 |<0.8; The focal length of the ninth lens (9) is f9, f 200 and f9 satisfy the relationship: 0.48<|f 200 / f9|<0.88; The focal length of the tenth lens (10) is f 10 , f 200 and f 10 Satisfies the relationship: 0.3<|f200 / f10|<0.7; The combined focal length of the second rear group (300) is f 300 , the focal length of the cemented lens U4 is f U4 , f 300 and f U4 Satisfies the relationship: 1.5<|f 300 / f U4 |<2.5; The focal length of the thirteenth lens (13) is f 13 , f 300 and f 13 Satisfies the relationship: 1<|f 300 / f 13 |<1.7; The focal length of the fourteenth lens (14) is f 14 , f 300 and f 14 Satisfies the relationship: 0.2<|f 300 / f 14 |<0.

8.

5. The optical system of a high-precision measurement lens according to claim 3, characterized in that: The first lens (1) and the fourth lens (4) are both biconvex lenses, the second lens (2), the fifth lens (5) and the sixth lens (6) are all meniscus lenses, and the third lens (3) is a plano-convex lens or a meniscus lens.

6. The optical system of a high-precision measurement lens according to claim 4, characterized in that: The ninth lens (9) and the tenth lens (10) are both meniscus lenses; The eleventh lens (11) is a biconcave lens, the twelfth lens (12) is a biconvex lens, the thirteenth lens (13) is a meniscus lens, and the fourteenth lens (14) is a meniscus lens or a plano-convex lens.

7. The optical system for high-precision lens measurement according to claim 1, characterized in that: The dichroic prism is a semi-transparent and semi-reflective prism.

8. The optical system for high-precision lens measurement according to claim 1, characterized in that: The fifth lens (5), the eighth lens (8), the ninth lens (9), the twelfth lens (12) and the thirteenth lens (13) are all made of crown glass.

9. The optical system for high-precision lens measurement according to claim 1, characterized in that: The apertures of the first aperture and the second aperture are both circular holes, and the centers of the two apertures are both on the optical axis of the optical system.

10. A high-precision measuring lens, characterized in that: An optical system comprising a high-precision measuring lens as described in any one of claims 1-9.

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