Lightweight head-mounted medical detection lens and optical system

Abstract

The utility model discloses a light-weight head-mounted medical detection lens. The lens sequentially comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens from an object side to an image side along an optical axis. The first lens has positive diopter, the object side surface is a convex surface, and the image side surface is a concave surface; the second lens has negative diopter, the object side surface is a concave surface, and the image side surface is a concave surface; the third lens has positive diopter, the object side surface is a convex surface, and the image side surface is a convex surface; the fourth lens has positive diopter, the object side surface is a convex surface, the image side surface is a convex surface, and the refractive index is shown in the specification; the fifth lens has negative diopter, and the object side surface of the fifth lens is a concave surface; the image side surface is a concave surface and has a refractive index; the sixth lens has positive diopter, the object side surface is a plane, and the image side surface is a convex surface; the seventh lens has negative diopter, the object side surface is a concave surface, and the image side surface is a plane.

Description

Technical Field

[0001] The utility model relates to the technical field of lens optical systems, in particular to a lightweight head-mounted medical detection lens and an optical system. Background Art

[0002] 1. To meet the needs of high-resolution imaging, conventional fixed-focus lenses mostly need to use relatively expensive aspherical glass lenses.

[0003] 2. Conventional lenses are limited by the focal depth of the system, and the object distance range that can be used for imaging is generally not large.

[0004] 3. Head-mounted lenses are mainly limited by the weight of the entire device. If they are too heavy, it will affect the comfort when worn on the head. Therefore, lightweight design is the design focus of this lens.

[0005] 4. Head-mounted lenses are also limited by the size of the entire device. If the size is too large, it will block the field of vision when worn on the head, so head-mounted medical detection lenses need to be as small as possible. Utility Model Content

[0006] The purpose of the utility model is to solve the above-mentioned problem and provide a lightweight head-mounted medical detection lens.

[0007] The technical solution of the utility model is achieved in this way:

[0008] In a first aspect, the utility model provides a lightweight head-mounted medical detection lens, wherein the lens comprises a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in order from the object side to the image side along the optical axis.

[0009] The first lens has positive refractive power, the object side surface is convex, the image side surface is concave, and the refractive index is: 1.8;

[0010] The second lens has a negative refractive power, a concave object side surface, a concave image side surface, and a refractive index of 1.6;

[0011] The third lens has positive refractive power, the object side surface is convex, the image side surface is convex, and the refractive index is: 1.8;

[0012] The fourth lens has positive refractive power, the object side surface is convex, the image side surface is convex, and the refractive index is: 1.6-1.8;

[0013] The fifth lens has a negative refractive power, the object side surface is concave, the image side surface is concave, and the refractive index is: 1.6 to 1.85;

[0014] The sixth lens has positive refractive power, a flat object side surface, a convex image side surface, and a refractive index of 1.8;

[0015] The seventh lens has negative refractive power, the object side surface is concave, the image side surface is flat, and the refractive index is 1.8.

[0016] The advantages or beneficial effects of the above technical solution include at least:

[0017] 1. When designing with spherical glass lenses, not only must the imaging quality requirements be met, but the production costs must also be considered.

[0018] 2. The lens must meet the requirements of wide working distance imaging of 200mm-700mm, and the minimum working distance for imaging is 200mm.

[0019] 3. The whole machine must not only meet the requirements of lightweight, but also its size must be as small as possible;

[0020] 4. This lens needs to be used with a 12-megapixel target surface, and has high requirements for image quality.

[0021] 5. In order to adapt to changes in ambient temperature, the lens also needs to ensure normal imaging within a certain temperature range.

[0022] In a second aspect, the present disclosure provides an optical system comprising the lightweight head-mounted medical detection lens described in any one of the above items.

[0023] The beneficial effects of this optical system have been clearly explained in the above-mentioned long-eye distance eyepiece, so they will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings show exemplary implementations of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are included in and constitute a part of this specification.

[0025] Figure 1 The MVF diagram of the first embodiment of the utility model is shown;

[0026] Figure 2 The distortion curve of the first embodiment of the utility model is shown;

[0027] Figure 3 The vertical axis chromatic aberration diagram of the first embodiment of the utility model is shown;

[0028] Figure 4 The lens arrangement diagram of the first embodiment of the utility model is shown (from left to right, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the filter, the protective sheet and the image plane);

[0029] Figure 5 The MVF diagram of the second embodiment of the utility model is shown;

[0030] Figure 6 The distortion curve of the second embodiment of the utility model is shown;

[0031] Figure 7 The vertical axis chromatic aberration diagram of the second embodiment of the utility model is shown;

[0032] Figure 8 The lens arrangement diagram of the second embodiment of the utility model is shown (from left to right, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the filter, the protective sheet and the image plane); DETAILED DESCRIPTION

[0033] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0034] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] It should be understood that the term "including" and its variations used in this article are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc. mentioned in the utility model are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0036] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0037] The names of the messages or information exchanged between multiple devices in the implementation manner of the present utility model are only used for illustrative purposes, and are not used to limit the scope of these messages or information.

[0038] A lightweight head-mounted medical detection lens comprises a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens in sequence from the object side to the image side along the optical axis.

[0039] The first lens has positive refractive power, the object side is convex, the image side is concave, and the refractive index is 1.8;

[0040] The second lens has negative refractive power, the object side is concave, the image side is concave, and the refractive index is: 1.6;

[0041] The third lens has positive refractive power, the object side surface is convex, the image side surface is convex, and the refractive index is: 1.8;

[0042] The fourth lens has positive refractive power, the object side surface is convex, the image side surface is convex, and the refractive index is: 1.6 to 1.8; preferably, the refractive index is 1.6 or 1.8;

[0043] The fifth lens has a negative refractive power, the object side surface is concave, the image side surface is concave, and the refractive index is: 1.6 to 1.85; preferably, the refractive index is 1.6 or 1.85;

[0044] The sixth lens has positive refractive power, the object side surface is flat, the image side surface is convex, and the refractive index is: 1.8;

[0045] The seventh lens has negative refractive power, the object side surface is concave, the image side surface is flat, and the refractive index is 1.8.

[0046] This patented lens uses a total of seven spherical lenses. By reasonably allocating the optical focal length of each lens, it meets the imaging quality requirements and reduces production costs. The maximum aperture of the optical lens is no more than 6.3mm and can be used with the M8 interface. Furthermore, the overall dimensions of the whole machine are 9mm*13.5mm and the weight is less than 3g, meeting the lightweight design requirements.

[0047] In addition, the fourth lens and the fifth lens are combined into a cemented lens, and the sixth lens and the seventh lens are combined into a cemented lens, and the cemented lenses all satisfy the relationship: |Vdpositive-Vd||>24; wherein Vdpositive is the Abbe number of the positive lens, and Vdnegative is the Abbe number of the negative lens; such a lens combination can not only effectively correct chromatic aberration, but also greatly help to improve the imaging clarity of the off-axis field of view.

[0048] Furthermore, the lens can be used with a 12-megapixel target surface, and the imaging quality is relatively uniform throughout the field of view. The working object distance range of the optical system is 200mm to 700mm. When the object distance changes, the focus can be adjusted by changing the optical back focus.

[0049] Furthermore, the optical system of the lens satisfies the following relationship: dn4 / Dt<0; wherein dn4 / Dt is the refractive index temperature coefficient of the fourth lens; such a setting is conducive to the optical athermal design of the system, ensuring clear imaging of the system in high and low temperature environments.

[0050] Furthermore, the optical system of the lens satisfies the following relationship: 1.5<|t / f|<1.7; wherein t is the total length of the optical system, and f is the focal length of the optical system.

[0051] Furthermore, the optical system of the lens satisfies the following relationship: nd1>1.8, 16<|f1|<18; wherein f1 is the focal length of the first lens, and nd1 is the refractive index of the first lens; this is conducive to controlling the maximum aperture of the system.

[0052] In the first embodiment, the parameters of the first to fifth lenses are shown in Table 1:

[0053] Table 1:

[0054]

[0055] Among them, the focal length parameters of the first to fifth lenses are shown in Table 2:

[0056] Table 2:

[0057] LENS focal length (1-2)P1 16.4 (3-4)P2 -7.3 (6-7)P3 9.1 (8-9)P4 5 (9-10)P5 -4.2 (11-12)P6 8.3 (12-13)P7 -14.2 (13-15)P8 Infinity (16-17)P9 Infinity

[0058] In the second embodiment, the parameters of the first to fifth lenses are shown in Table 3:

[0059] Table 3:

[0060]

[0061] Among them, the focal length parameters of the first to fifth lenses are shown in Table 4:

[0062] Table 4:

[0063] LENS focal length (1-2)P1 13.9 (3-4)P2 -7.8 (6-7)P3 10.7 (8-9)P4 4.4 (9-10)P5 -3.5 (11-12)P6 9.1 (12-13)P7 -16.6 (13-15)P8 Infinity (16-17)P9 Infinity

[0064] The comparison of optical system parameters of the first embodiment and the second embodiment is shown in Table 5:

[0065] Table 5:

[0066] Example 1 Example 2 f 11.4 11.5 BFL 6.9 6.5 BFL / f 0.60526322 0.565217 y 8 8 y / f 0.7017544 0.695652 TTL 18.53 18.93 BFL / TTL 0.3723691 0.34337

[0067] Wherein, f is the focal length of the optical system; BFL is the optical back focus of the optical system; y is the image height (the total image height of the image on the sensor); the unit of TTL optical total length (the distance from the first surface of the first lens to the image plane) is: mm.

[0068] The present application also provides an optical system, comprising any of the lightweight head-mounted medical detection lenses described above; the beneficial effects of this optical system have been clearly explained in the above-mentioned lightweight head-mounted medical detection lenses and will not be repeated here.

[0069] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0070] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A lightweight head-mounted medical detection lens, characterized in that: The lens comprises a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in order from the object side to the image side along the optical axis; The first lens has positive refractive power, the object side surface is convex, the image side surface is concave, and the refractive index is: 1.8; The second lens has a negative refractive power, a concave object side surface, a concave image side surface, and a refractive index of 1.6; The third lens has positive refractive power, the object side surface is convex, the image side surface is convex, and the refractive index is: 1.8; The fourth lens has positive refractive power, the object side surface is convex, the image side surface is convex, and the refractive index is: 1.6-1.8; The fifth lens has negative refractive power, the object side surface is concave, the image side surface is concave, and the refractive index is: 1.6 to 1.85; The sixth lens has positive refractive power, the object side surface is a flat surface, the image side surface is a convex surface, and the refractive index is: 1.8; The seventh lens has negative refractive power, the object side surface is concave, the image side surface is flat, and the refractive index is 1.

8.

2. The lightweight head-mounted medical detection lens according to claim 1, characterized in that: The fourth lens and the fifth lens are combined into a cemented lens, and the sixth lens and the seventh lens are combined into a cemented lens.

3. The lightweight head-mounted medical detection lens according to claim 2, characterized in that: The glued lenses all satisfy the relationship: |Vd 正 -Vd||>24; Where Vd 正 is the Abbe number of the positive lens, Vd 负 is the Abbe number of the negative lens.

4. The lightweight head-mounted medical detection lens according to claim 1, characterized in that: The optical system of the lens satisfies the following relationship: dn4 / Dt<0; wherein dn4 / Dt is the refractive index temperature coefficient of the fourth lens.

5. The lightweight head-mounted medical detection lens according to claim 1, characterized in that: The optical system of the lens satisfies the following relationship: 1.5<|t / f|<1.7; wherein t is the total length of the optical system, and f is the focal length of the optical system.

6. The lightweight head-mounted medical detection lens according to claim 1, characterized in that: The optical system of the lens satisfies the following relationship: nd1>1.8, 16<|f1|<18; wherein f1 is the focal length of the first lens, and nd1 is the refractive index of the first lens.

7. The lightweight head-mounted medical detection lens according to claim 1, characterized in that: The maximum aperture of the lens is no greater than 6.3 mm.

8. An optical system, characterized in that: It comprises a lightweight head-mounted medical detection lens as described in any one of claims 1-7.

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