Sammer lens and electronic equipment

Abstract

The invention, which relates to the technical field of the optical system, discloses a Sammer lens and an electronic device wherein the Sammer lens comprises a plurality of lens groups which are sequentially arranged from an object plane to an image plane, and an optical axis is correspondingly formed between the plurality of lens groups. The plurality of lens groups comprise a first lens group with positive focal power, a second lens group with positive focal power, a third lens group with positive focal power, a fourth lens group with positive focal power and a fifth lens group with negative focal power; the aperture number of the Sammer lens is F, and F is less than 3; the lens angle alpha of the Sammer lens is greater than or equal to 40 degrees and less than or equal to 50 degrees; according to the scheme, the large-clear-aperture far-object-space high-performance fixed-focus lens design is realized by adopting a structure of seven spherical lenses, wherein F # is 2.98, object space 45-degree large-dip-angle imaging is realized, 100pl / mm is 0.337 MTF, the average distortion is 0.1822%, and the working wavelength is 470nm + / -10nm. The large-clear-aperture far-object-space high-performance fixed-focus lens design has the advantages that the F # is 2.98, the object space is 45-degree large-dip-angle imaging is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of optical systems, and in particular to a Sham lens and electronic equipment. Background Art

[0002] Scheimpflug lens is also called tilt-shift lens. According to Scheimpflug's law, it can make the image plane and the object plane have a certain angle. It is often used in stereoscopic structured light photography to increase the 3D imaging range. The commercially available Scheimpflug lens has a small working F# (5-8) and a small object tilt angle. This type of lens generally does not consider the change in magnification caused by the defocus of the target.

[0003] In some special measurement scenarios, for example, dynamic analysis of the cornea requires a higher sampling speed, such as a single-frame sampling time of <0.3ms, so a higher light flux is required; at the same time, it is necessary to meet the low distortion requirement that the corneal movement defocus does not affect the position relationship of the measurement structure; in addition, it is also necessary to ensure that the human face does not interfere with the optical path structure. In the above usage scenarios, the existing Sham lenses are difficult to take into account the requirements of light throughput, large angles and low distortion. Summary of the invention

[0004] The main purpose of the present invention is to provide a Sham lens and an electronic device, aiming to solve the problem that the existing Sham lens is difficult to take into account the requirements of light transmission, large angle and low distortion.

[0005] To achieve the above object, the Sham lens proposed in the present invention comprises a plurality of lens groups arranged in sequence from the object plane to the image plane, wherein an optical axis is formed between the plurality of lens groups, and the plurality of lens groups comprise a first lens group with positive focal power, a second lens group with positive focal power, a third lens group with positive focal power, a fourth lens group with positive focal power, and a fifth lens group with negative focal power;

[0006] The aperture number of the Sham lens is F, F<3;

[0007] The lens angle of the Sham lens is α, 40°≤α≤50°.

[0008] In one embodiment, the first lens group includes a first lens;

[0009] The second lens group includes a second lens and a third lens;

[0010] The third lens group includes a fourth lens and a fifth lens;

[0011] The fourth lens group includes a sixth lens;

[0012] The fifth lens group includes a seventh lens.

[0013] In one embodiment, the first lens is a positive meniscus lens, the object side of which is concave;

[0014] The second lens is a biconvex lens, and the third lens is a biconcave lens;

[0015] The fourth lens is a convex-concave lens, and its object side surface is convex;

[0016] The fifth lens is a biconvex lens or a plano-convex lens, and its object surface side is convex;

[0017] The sixth lens is a biconvex lens or a plano-convex lens, and its object surface side is correspondingly a convex surface or a flat surface;

[0018] The seventh lens is a meniscus lens, and its object surface side is concave.

[0019] In one embodiment, a distance Wr between the object plane and the first lens is 75 mm to 80 mm, and a distance Wq between the seventh lens and the image plane is 46.5 mm to 48.5 mm.

[0020] In one embodiment, the working wavelength WL of the Sham lens is 460nm-480nm, the working magnification β of the Sham lens is 0.8-1, and the imaging distortion of the Sham lens is less than 0.2%.

[0021] In one embodiment, the Sham lens further includes an aperture stop, wherein the aperture stop is disposed between the third lens and the fourth lens, and a pupil diameter of the Sham lens is Ds, where Ds>19 mm.

[0022] In one embodiment, the second lens and the third lens are configured as a doublet lens, and the fourth lens and the fifth lens are configured as a doublet lens.

[0023] In one embodiment, the refractive index and the Abbe number of the second lens are greater than the refractive index and the Abbe number of the third lens, and the refractive index and the Abbe number of the fourth lens are less than the refractive index and the Abbe number of the fifth lens; and / or,

[0024] The second lens and the third lens are made of different glass materials; and / or,

[0025] The fourth lens and the fifth lens are made of different glass materials.

[0026] In one embodiment, the curvatures of the object side and the image side of the second lens are equal.

[0027] The present invention further provides an electronic device, comprising a Sham lens, wherein the Sham lens comprises a plurality of lens groups arranged in sequence from an object plane to an image plane, wherein an optical axis is formed between the plurality of lens groups, and wherein the plurality of lens groups comprise a first lens group having positive focal power, a second lens group having positive focal power, a third lens group having positive focal power, a fourth lens group having positive focal power, and a fifth lens group having negative focal power;

[0028] The aperture number of the Sham lens is F, F<3;

[0029] The lens angle of the Sham lens is α, 40°≤α≤50°.

[0030] The technical solution of the present invention adopts the fixed-focus lens provided by the embodiment of the present invention, and adopts a 7-piece spherical lens structure to achieve an F# of 2.98, 45° large-angle imaging in the object side, 0.337 MTF at 100pl / mm, an average distortion of 0.1822%, and a high-performance fixed-focus Sham lens design with a large aperture and a long object side of a working wavelength of 470nm±10nm. It can effectively meet the use requirements in some special measurement scenarios, such as corneal dynamic analysis, etc., make up for some problems existing in existing Sham lenses, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of the lens structure layout of the Sham lens provided for this solution;

[0033] Figure 2 for Figure 1 The schematic diagram of the MTF curve of the Sham lens on the image plane is provided in;

[0034] Figure 3 for Figure 1 A structural schematic diagram of another embodiment of a Sham lens provided in FIG.

[0035] Description of Figure Numbers:

[0036] 100. Sham lens; 1. first lens group; 11. first lens; 2. second lens group; 21. second lens; 22. third lens; 3. third lens group; 31. fourth lens; 32. fifth lens; 4. fourth lens group; 41. sixth lens; 5. fifth lens group; 51. seventh lens; 6. object plane; 7. image plane; 8. aperture.

[0037] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0038] 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.

[0039] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0040] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] Scheimpflug lens is also called tilt-shift lens. According to Scheimpflug's law, it can make the image plane and the object plane have a certain angle. It is often used in stereoscopic structured light photography to increase the 3D imaging range. The commercially available Scheimpflug lens generally has a small working F# (5-8) and a small object tilt angle. This type of lens generally does not consider the change in magnification caused by the defocus of the target.

[0042] In some special measurement scenarios, for example, dynamic analysis of the cornea requires a higher sampling speed, such as a single-frame sampling time of <0.3ms, so a higher light flux is required; at the same time, it is necessary to meet the low distortion requirement that the corneal movement defocus does not affect the position relationship of the measurement structure; in addition, it is also necessary to ensure that the human face does not interfere with the optical path structure. In the above usage scenarios, the existing Sham lenses are difficult to take into account the requirements of light throughput, large angles and low distortion.

[0043] The present invention proposes a Sham lens 100 for solving the above problems.

[0044] See also Figures 1 to 3 The Sham lens is also called a tilt-shift lens. According to Sham's law, it can make the image plane and the object plane have a certain angle. When the extended lines of the target plane, the main surface of the lens and the imaging plane intersect in a line, the entire tilted target field of view can be clearly imaged. Therefore, it is often used in stereoscopic structured light photography to increase the 3D imaging range. However, in some special measurement scenarios, such as the process of dynamic analysis of the cornea, it is difficult for traditional Sham lenses to take into account the requirements of light throughput, large angles and low distortion. In this embodiment, in order to solve the above problems. A Sham lens 100 is proposed, wherein the Sham lens 100 comprises a first lens group 1 with positive focal power, a second lens group 2 with positive focal power, a third lens group 3 with positive focal power, a fourth lens group 4 with positive focal power and a fifth lens group 5 with negative focal power, which are arranged in sequence from an object plane 6 to an image plane 7, wherein the fifth lens group 5 is used to adjust the distance between the lens and a CCD and the image height, and the above multiple lens groups have the same optical axis. The arrangement of the above lens group structure can realize large-angle imaging of the Sham lens 100, and at the same time enable the Sham lens 100 to have a suitable working distance, which has a significant improvement effect. Specifically, the working distance Wd of the Sham lens 100 is 70mm to 90mm; the lens angle α can reach a range of 45°±5°; when in use, its aperture number F can reach 2.4, and it has good light throughput. During corneal dynamic analysis, the single-frame sampling time is less than 0.3ms. The light throughput in this embodiment can well meet its requirements. At the same time, the working distance is long enough to effectively avoid interference between the face and the optical path structure, which affects the imaging quality. The lens angle can reach 50°, which has a wider 3D imaging range than the traditional Sham lens. When performing corneal dynamic analysis, it can try to obtain imaging information of specific 3D images on both sides of the cornea, which can provide sufficient information support for subsequent analysis.

[0045] Specifically, the specific lens composition included in the multiple lens groups is as follows: the first lens group 1 includes a first lens 11; the second lens group 2 includes a second lens 21 and a third lens 22; the third lens group 3 includes a fourth lens 31 and a fifth lens 32; the fourth lens group 4 includes a sixth lens 41; the fifth lens group 5 includes a seventh lens 51. The Sham lens 100 is composed of seven lens structures, and the above seven lenses are arranged in sequence from the object plane 6 to the image plane 7, and together constitute the main imaging structure of the Sham lens 100.

[0046] Among them, the focal length of the first lens group 1 is 160 mm; the focal length of the second lens group 2 is 374 mm; the focal length of the third lens group 3 is 91 mm; the focal length of the fourth lens group 4 is 109 mm; and the focal length of the fifth lens group 5 is -171 mm.

[0047] The specific surface configurations of the above multiple lenses in the Sham lens 100 are as follows:

[0048] The first lens 11 is a positive meniscus lens, and its object plane 6 side is concave; the second lens 21 is a biconvex lens, wherein the curvature of the second lens 21 on the object plane 6 side and the image plane 7 side is preferably set to be equal, and the third lens 22 is a biconcave lens; the fourth lens 31 is a convex-concave lens, and its object side is convex; the fifth lens 32 is a biconvex lens or a plano-convex lens, and its object plane 6 side is convex; the sixth lens 41 is a biconvex lens or a plano-convex lens, and its object plane 6 side is correspondingly convex or flat; the seventh lens 51 is a concave-convex lens, and its object plane 6 side is concave. Among them, the seventh lens 51 is a concave-convex lens with negative optical power, which is mainly used to adjust the distance between the lens and the CCD and the image height.

[0049] Among them, the distance Wr between the object plane 6 and the first lens 11 is 75mm-80mm, and the distance Wq between the seventh lens 51 and the image plane 7 is 46.5mm-48.5mm, which can compensate for the assembly error in the process of lens structure installation. The above specific settings of the first lens 11 and the seventh lens 51, combined with the specific focal length value design of the first lens 11 to the seventh lens 51, can make the entire Sham lens 100 form an object telecentric structure setting. Under the premise of having a large object tilt angle, when it cannot focus accurately, its imaging magnification can also remain relatively stable, avoiding the situation that the magnification changes caused by the small light transmission and object tilt angle of the traditional Sham lens after the target is defocused. If the magnification changes, the corresponding actual measurement data will be affected, and the accuracy of the measurement data will be affected during the measurement process. By adopting the above structure in this embodiment, the distortion of the Sham lens 100 can be controlled below 0.2%.

[0050] Wherein, the working wavelength WL of the Sham lens 100 is 460nm-480nm.

[0051] In order to ensure that the entire Sham lens 100 has a larger light-transmitting aperture, in this embodiment, the pupil diameter is greater than 19 mm.

[0052] The second lens 21 and the third lens 22 are configured as doublet lenses, and the fourth lens 31 and the fifth lens 32 are configured as doublet lenses. However, the second lens 21 and the third lens 22 are made of different glass materials, and the fourth lens 31 and the fifth lens 32 are made of different glass materials.

[0053] The refractive index and Abbe number of the second lens 21 are greater than those of the third lens 22, and the refractive index and Abbe number of the fourth lens 31 are less than those of the fifth lens 32. For details, the relevant parameters can be referred to in Table 1 below.

[0054] The design parameters of each lens in the Sham lens 100 are as follows:

[0055] Table 1

[0056]

[0057]

[0058] The Sham lens 100 in this solution uses a 7-piece spherical lens structure to achieve an F# of 2.98, 45° large-angle imaging in the object direction, 0.337 MTF at 100pl / mm, an average distortion of 0.1822%, and a high-performance fixed-focus Sham lens design with a large aperture and a long object direction of 470nm±10nm working wavelength. It can effectively meet the use requirements in some special measurement scenarios, such as corneal dynamic analysis, and make up for some problems of existing Sham lenses, and has good application prospects.

[0059] In another embodiment, the Sham lens 100 has another embodiment structure in addition to the above embodiment contents, such as Figure 3 As shown, inserting a reflective lens between the first lens 11 and the second lens 21 can achieve folding of the light path, shortening the total length of the light path, or shortening the distance between the first lens 11 and the second lens 21 to shorten the total length of the light path.

[0060] The present invention further proposes an electronic device, which includes a Sham lens 100. The specific structure of the Sham lens 100 refers to the above-mentioned embodiment. Since the electronic device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0061] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention and the drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A Sham lens, characterized in that: The invention comprises a plurality of lens groups arranged in sequence from the object plane to the image plane, wherein an optical axis is formed between the plurality of lens groups, and the plurality of lens groups comprise a first lens group with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, and a fifth lens group with negative optical power; The aperture number of the Sham lens is F, F<3; The lens angle of the Sham lens is α, 40°≤α≤50°.

2. The Sham lens according to claim 1, wherein: The first lens group includes a first lens; The second lens group includes a second lens and a third lens; The third lens group includes a fourth lens and a fifth lens; The fourth lens group includes a sixth lens; The fifth lens group includes a seventh lens.

3. The Sham lens according to claim 2, wherein: The first lens is a positive meniscus lens, the object side of which is concave; The second lens is a biconvex lens, and the third lens is a biconcave lens; The fourth lens is a convex-concave lens, and its object side surface is convex; The fifth lens is a biconvex lens or a plano-convex lens, and its object surface side is convex; The sixth lens is a biconvex lens or a plano-convex lens, and its object surface side is correspondingly a convex surface or a flat surface; The seventh lens is a meniscus lens, and its object surface side is concave.

4. The Sham lens according to claim 3, characterized in that: The distance Wr between the object plane and the first lens is 75 mm to 80 mm, and the distance Wq between the seventh lens and the image plane is 46.5 mm to 48.5 mm.

5. The Sham lens according to claim 3, characterized in that: The working wavelength WL of the Sham lens is 460nm-480nm, the working magnification β of the Sham lens is 0.8-1, and the imaging distortion of the Sham lens is less than 0.2%.

6. The Sham lens according to claim 3, wherein: The Sham lens further includes an aperture stop, which is disposed between the third lens and the fourth lens, and a pupil diameter of the Sham lens is Ds, where Ds>19 mm.

7. The Sham lens according to claim 3, characterized in that: The second lens and the third lens are configured as a doublet lens, and the fourth lens and the fifth lens are configured as a doublet lens.

8. The Sham lens according to claim 3, wherein: The refractive index and Abbe number of the second lens are greater than those of the third lens, and the refractive index and Abbe number of the fourth lens are smaller than those of the fifth lens; and / or, The second lens and the third lens are made of different glass materials; and / or, The fourth lens and the fifth lens are made of different glass materials.

9. The Sham lens according to claim 3, wherein: The curvatures of the object side and the image side of the second lens are equal.

10. An electronic device, characterized in that: Including the Sham lens described in any one of claims 1-9.

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