3.7 mm focal length glass-plastic hybrid lens and electronic equipment

Abstract

The utility model discloses a 3.7 mm focal length glass-plastic hybrid lens and an electronic device. The lens comprises a lens frame and a lens group arranged in the lens frame; the lens group sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens from an object side to an image side, wherein the first lens has negative 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 convex surface; the third lens has positive diopter, the object side surface is a concave surface, and the image side surface is a convex surface; the fourth lens has positive diopter, the object side surface is a convex surface, and the image side surface is a convex surface; the fifth lens has negative diopter, the object side surface is a convex surface, and the image side surface is a concave surface. Through reasonable light angle distribution, the optical imaging lens designed by the utility model has the advantages of large field angle, large target surface and low glass-plastic mixed cost.

Description

Technical Field

[0001] The utility model relates to the technical field of security lenses, and particularly relates to a 3.7mm focal length glass-plastic hybrid lens and an electronic device. Background Technique

[0002] Ordinary security lenses are usually used in video surveillance systems, and their types and specifications are diverse to meet different monitoring environments and requirements. According to whether the focal length is variable, security lenses can be divided into fixed-focus lenses, manual zoom lenses, and motorized zoom lenses. Fixed-focus lenses are suitable for monitoring fixed locations, such as cultural relic exhibition stands or toll windows, because of their low cost. Zoom lenses are suitable for scenarios where the best focus point cannot be determined, such as narrow passages, providing greater flexibility. Motorized zoom lenses are usually used for monitoring large scenes and are often used in conjunction with pan-tilt heads. They have a large zoom range and can observe a large range and focus on details at the same time. Existing security lenses have at least one of the following disadvantages:

[0003] 1) The field of view angle is small, and the lens capture range is not large enough;

[0004] 2) The imaging target surface is small, the signal-to-noise ratio is high, and the photosensitive performance is poor;

[0005] 3) Too many glass lenses are used, making the overall cost of the lens too high. Content of the Utility Model

[0006] In view of this, the purpose of the utility model is to provide a 3.7mm focal length glass-plastic hybrid lens and an electronic device. This lens can solve at least one of the technical disadvantages mentioned in the background technique.

[0007] According to one aspect of the utility model, a 3.7mm focal length glass-plastic hybrid lens is provided, which includes a lens frame and a lens group disposed inside the lens frame; the lens group is, in order from the object side to the image side: the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens;

[0008] Among them:

[0009] The first lens has a negative refractive power, the object side is a convex surface, and the image side is a concave surface;

[0010] The second lens has a negative refractive power, the object side is a concave surface, and the image side is a convex surface;

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

[0012] The fourth lens has a positive refractive power, the object side is a convex surface, and the image side is a convex surface;

[0013] The fifth lens has a negative refractive power, the object side is a convex surface, and the image side is a concave surface;

[0014] The sixth lens has a positive refractive power, with a convex object side and a convex image side;

[0015] The seventh lens has a negative refractive power, with a concave object side and a concave image side;

[0016] The eighth lens has a positive refractive power, with a convex object side and a convex image side;

[0017] The sixth lens and the seventh lens are cemented into a first cemented lens group.

[0018] In the above technical solution, by reasonably allocating the light angles, an optical imaging lens is designed with the advantages of a large field of view angle, a large target surface, and a low cost of glass-plastic hybrid.

[0019] In some embodiments, the first lens, the fourth lens, the sixth lens, and the seventh lens are glass lenses;

[0020] The second lens, the third lens, the fifth lens, and the eighth lens are plastic lenses.

[0021] In the above technical solution, the optics uses 8 lenses, 4 glass lenses and 4 plastic lenses. Compared with traditional all-glass lenses, it is lighter in weight and lower in cost.

[0022] In some embodiments, the lens satisfies the following conditional formula:

[0023] TTL < 31 mm; FOV ≥ 162°;

[0024] In the formula, TTL is the overall optical length of the lens; FOV is the field of view angle of the lens.

[0025] In the above technical solution, by satisfying the above conditional formula, the lens is small in volume, making it convenient to install and use, and at the same time having a relatively large picture size to meet the requirements of monitoring.

[0026] In some embodiments, the first lens is fixed to the object-side end of the lens frame through a retaining ring structure.

[0027] In the above technical solution, the retaining ring structure is fixed to the lens frame by means of threading and the bevel at the tail through dotting. In terms of material, the retaining ring is made of metal, which has higher wear resistance; in terms of performance, using the retaining ring structure has better waterproofness under extreme conditions; in terms of the assembly process, the retaining ring structure is convenient for repair and reduces the scrapping of materials, reducing production costs.

[0028] In some embodiments, the first lens and the second lens are separated by a first mylar sheet;

[0029] The second lens and the third lens are separated by a second Mylar sheet;

[0030] The third lens and the fourth lens are separated by a first spacer ring;

[0031] The fourth lens and the fifth lens are separated by a second spacer ring;

[0032] The fifth lens and the first cemented lens group are sequentially separated by a third Mylar sheet and a third spacer ring;

[0033] The first cemented lens group and the eighth lens are separated by a fourth spacer ring.

[0034] In some embodiments, the image-side end interface of the lens frame is M16.

[0035] In the above technical solution, the M16 threaded interface is beneficial for customers to easily match multiple different bases.

[0036] In some embodiments, the lens frame is made of plastic material.

[0037] In the above technical solution, using plastic material for the lens frame reduces the lens cost.

[0038] According to another aspect of the present invention, there is provided an electronic device, including a 3.7 mm focal length glass-plastic hybrid lens as described above; and

[0039] An image sensor configured to receive an image formed by the 3.7 mm focal length glass-plastic hybrid lens.

[0040] In the above technical solution, the advantages of the electronic device rely on the 3.7 mm focal length glass-plastic hybrid lens, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] 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 use in 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, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a schematic diagram of the lens group structure of Example 1 of a 3.7 mm focal length glass-plastic hybrid lens of the present invention;

[0043] Figure 2 It is a schematic diagram of the lens structure of Example 1 of a 3.7 mm focal length glass-plastic hybrid lens of the present invention;

[0044] Figure 3It is a schematic diagram of the relative illumination of the lens of Example 1 of a 3.7mm focal length glass-plastic hybrid lens of the present utility model;

[0045] Figure 4 It is a field curvature and distortion curve graph of Example 1 of a 3.7mm focal length glass-plastic hybrid lens of the present utility model;

[0046] Figure 5 It is an MTF curve graph of Example 1 of a 3.7mm focal length glass-plastic hybrid lens of the present utility model;

[0047] Figure 6 It is a schematic structural diagram of Example 2 of an electronic device of the present utility model. Detailed implementation manners

[0048] The following will further describe the present utility model in detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are only used to illustrate the present utility model, but do not limit the scope of the present utility model. Similarly, the following embodiments are only partial embodiments of the present utility model rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model.

[0049] The purpose of the present utility model is to propose a 3.7mm focal length glass-plastic hybrid lens and an electronic device with high optical performance. Embodiments according to the present utility model will now be described in detail with reference to the accompanying drawings.

[0050] Figure 1 、 Figure 2 It is a sectional view of a 3.7mm focal length glass-plastic hybrid lens (optical system) according to Example 1 and a sectional view when the lens group is installed in the lens frame. The 3.7mm focal length glass-plastic hybrid lens according to Example 1 is used in imaging devices such as digital cameras, digital still cameras, broadcast cameras, surveillance cameras, etc. and optical devices with interchangeable lenses. In each sectional view, the left side is the object side OBJ and the right side is the image side IMA, and the optical axis OA. In each sectional view, Gi represents the i-th lens, and Ci represents the i-th lens unit. IMA represents the image plane. When the 3.7mm focal length glass-plastic hybrid lens according to Example 1 is used in an imaging optical system of a digital camera or a digital still camera, a solid-state imaging element (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor is arranged on the imaging plane IMA.

[0051] The 3.7mm focal length glass-plastic hybrid lens according to each example includes, in order from the object side to the image side: a lens frame 1, and a lens group 2 disposed inside the lens frame; the lens group is, in order from the object side to the image side: the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8; wherein:

[0052] The first lens G1 has a negative diopter, with a convex object side and a concave image side;

[0053] The second lens G2 has a negative diopter, with a concave object side and a convex image side;

[0054] The third lens G3 has a positive diopter, with a concave object side and a convex image side;

[0055] The fourth lens G4 has a positive diopter, with a convex object side and a convex image side;

[0056] The fifth lens G5 has a negative diopter, with a convex object side and a concave image side;

[0057] The sixth lens G6 has a positive diopter, with a convex object side and a convex image side;

[0058] The seventh lens G7 has a negative diopter, with a concave object side and a concave image side;

[0059] The eighth lens G8 has a positive diopter, with a convex object side and a convex image side;

[0060] The sixth lens G6 and the seventh lens G7 are cemented into a first cemented lens group C1.

[0061] Among them, the first lens G1, the fourth lens G4, the sixth lens G6, and the seventh lens G7 are glass lenses; the second lens G2, the third lens G3, the fifth lens G5, and the eighth lens G8 are plastic lenses.

[0062] Among them, please refer to Figure 2 , the first lens G1 is fixed to the object-side end of the lens frame 1 through the retaining ring 11 structure. The image-side end interface of the lens frame 1 is M16, and the lens frame 1 is made of plastic material. The first lens G1 and the second lens G2 are separated by the first mylar sheet 12; the second lens G2 and the third lens G3 are separated by the second mylar sheet 13; the third lens G3 and the fourth lens G4 are separated by the first spacer 15; the fourth lens G4 and the fifth lens G5 are separated by the second spacer 16; the fifth lens G5 and the first cemented lens group C1 are sequentially separated by the third mylar sheet 14 and the third spacer 17; the first cemented lens group C1 and the eighth lens G8 are separated by the fourth spacer 18.

[0063] The first lens is fixed by centering and dispensing with a centering machine, which is beneficial to improving the imaging quality of the lens. In the present utility model, the retaining ring structure is used to improve the overall aesthetics of the lens, and the outer diameter of the lens can also be changed by replacing different retaining rings. The retaining ring structure is fixed by dispensing at the beveled ends of the tail and the beveled ends of the lens frame. The main function of the first mylar sheet is to intercept the invalid light that may pass outside the effective diameter of the 01 piece, and the main function of the second mylar sheet is to intercept the invalid light that may pass outside the effective diameter of the 02 piece. The inside of the first spacer is serrated to effectively intercept stray light, with sharp corners provided inside to limit the size of the aperture stop, and chamfers are provided on both sides to prevent interference with the lens. The inside of the second spacer is also serrated to effectively prevent the appearance of stray light. The main function of the third mylar sheet is to correct field curvature, which can be added or not according to the actual situation. One side of the third spacer is a right-angle step for avoiding the cemented lens, and the other side is beveled to avoid generating stray light. The same applies to the fourth spacer.

[0064] The 3.7 mm focal length plastic-glass hybrid lens according to each example can meet at least one of the following setting conditions 1) to 3):

[0065] 1) TTL < 31 mm;

[0066] 2)

[0067] 3) FOV ≥ 162°;

[0068] In the above conditional expressions, TTL is the overall optical length of the lens; FOV is the field of view angle of the lens.

[0069] Conditional expression 1) defines the overall optical length of the lens. By appropriately setting the conditions, the volume of the lens is reduced, making it convenient for installation and use.

[0070] Conditional expression 2) defines the imaging range of the lens. By appropriately setting the conditions, the lens has a larger imaging target surface.

[0071] Conditional expression 3) defines the field of view angle of the lens. By appropriately setting the conditions, the lens has a larger field of view angle.

[0072] A detailed description of the plastic-glass hybrid lens according to each example will now be given.

[0073] For the optical structure of Example 1, please refer to Figure 1 , and the specific parameters of this Example 1 are shown in Table 1 below. In this Example 1, the focal length of the lens f' = 3.7 mm.

[0074] Table 1 Parameters of Example 1

[0075]

[0076] Please refer to Figure 3, Relative illuminance diagram of the optical system of Example 1, relative illuminance at visible light of 555 nm. It can be seen that the relative illuminance of the lens is greater than 45%.

[0077] Please refer to Figure 4 , Field curvature and distortion diagram of the optical system of Example 1. According to the image display, the field curvature curves of this example at wavelengths of 435 - 650 show that both the T-line and S-line have good convergence. The field curvature and astigmatism are both excellent, meeting the requirement of uniform imaging across the entire image plane.

[0078] Please refer to Figure 4 , MTF curve diagram of Example 1 Figure 1 is the MTF diagram at visible light of 435 - 650 nm in Example 1. The MTF value is greater than 0.3 at 83 lp / mm, indicating that this example has high resolution and good imaging quality.

[0079] Based on Example 1, this case has the following specific advantages:

[0080] 1. This lens has a 4G4P structure. Compared with traditional all-glass lenses, it is lighter in weight and lower in cost.

[0081] 2. The FOV of this lens is 162°, with a wide monitoring range, and the imaging target surface reaches

[0082] 3. The front end adopts a retaining ring design to avoid affecting the appearance due to the protrusion of the first lens G1.

[0083] 4. The lens frame uses plastic material to reduce the cost of the lens.

[0084] Example 2

[0085] Now refer to Figure 6 , a description of the electronic device A according to Example 2 of the present invention will be given. Figure 6 is a schematic diagram of an electronic device (industrial camera) that uses the 3.7 mm focal length glass-plastic hybrid lens according to Example 1 for a camera optical system.

[0086] In Figure 6 , reference numeral A2 represents the main body of the electronic device, and reference numeral A1 represents a camera optical system (interchangeable lens) including the 3.7 mm focal length glass-plastic hybrid lens according to Example 1. Reference numeral A3 represents an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor. The image sensor is built into the camera body A2 and receives light (the optical image formed by the camera optical system A1) from the camera optical system A1 and performs photoelectric conversion.

[0087] By using the 3.7 mm focal length hybrid glass-plastic lens according to Example 1 in an electronic device such as a digital still camera, an electronic device with a lens having high optical performance can be obtained.

[0088] Although the present utility model has been described with reference to exemplary embodiments, it should be understood that the present utility model is not limited to the disclosed exemplary embodiments. The scope of the following claims will be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A 3.7mm focal length hybrid glass-plastic lens, characterized in that, Comprising a lens frame, and a lens group disposed inside the lens frame; the lens group, from the object side to the image side in sequence, is: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens; wherein: The first lens has a negative refractive power and is a glass lens, the object side surface is convex, and the image side surface is concave; The second lens has a negative refractive power and is a plastic lens, the object side surface is concave, and the image side surface is convex; The third lens has a positive refractive power, the object side surface is concave, and the image side surface is convex; The fourth lens has a positive refractive power, the object side surface is convex, and the image side surface is convex; The fifth lens has a negative refractive power, the object side surface is convex, and the image side surface is concave; The sixth lens has a positive refractive power, the object side surface is convex, and the image side surface is convex; The seventh lens has a negative refractive power, the object side surface is concave, and the image side surface is concave; The eighth lens has a positive refractive power, the object side surface is convex, and the image side surface is convex; The sixth lens and the seventh lens are cemented into a first cemented lens group.

2. A 3.7mm focal length glass-plastic hybrid lens according to claim 1, wherein The first lens, the fourth lens, the sixth lens, and the seventh lens are glass lenses; The second lens, the third lens, the fifth lens, and the eighth lens are plastic lenses.

3. A 3.7mm focal length glass-plastic hybrid lens according to claim 1, wherein The lens satisfies the following conditional formula: TTL < 31 mm; FOV ≥ 162°; In the formula, TTL is the overall optical length of the lens; FOV is the field of view angle of the lens.

4. A 3.7mm focal length glass-plastic hybrid lens according to claim 1, wherein The first lens is fixed to the object side end of the lens frame through a retaining ring structure.

5. A 3.7mm focal length glass-plastic hybrid lens according to claim 1, wherein A first mylar sheet is disposed between the first lens and the second lens; A second mylar sheet is disposed between the second lens and the third lens; A first spacer is disposed between the third lens and the fourth lens; A second spacer is disposed between the fourth lens and the fifth lens; A third mylar sheet and a third spacer are sequentially disposed between the fifth lens and the first cemented lens group; A fourth spacer is disposed between the first cemented lens group and the eighth lens.

6. A 3.7mm focal length glass-plastic hybrid lens according to claim 1, wherein The image side end interface of the lens frame is M16.

7. A 3.7mm focal length glass-plastic hybrid lens according to claim 1, wherein The lens frame is made of plastic material.

8. An electronic device, characterized in that, A 3.7mm focal length glass-plastic hybrid lens according to any one of claims 1-7; and An image sensor, which is configured to receive the image formed by the 3.7mm focal length glass-plastic hybrid lens.

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