Zoom systems and camera equipment

Abstract

The present invention discloses a zoom system and an imaging device. The zoom system includes a first lens group, a second lens group, a third lens group, and a fourth lens group, which are arranged sequentially from the object side to the image side. The first lens group and the fourth lens group are fixed in position, and the second lens group and the fourth lens group are movable along the extension direction of the optical axis to have a movable range between being close to the object side and close to the image side. The refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group, the second lens group, and the fourth lens group are controlled so that the zoom system can achieve a clear image when a 3x magnification is achieved. This provides a zoom system with a low-cost design and high-definition imaging magnification while ensuring a 3x magnification.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a zoom system and a camera device. Background Art

[0002] Currently, security systems generally have the following shortcomings: high lens cost and poor imaging quality. In order to solve the above problems, the present invention provides a low-cost high-definition imaging lens. Summary of the Invention

[0003] The main purpose of the present invention is to propose a zoom system and a camera device, aiming to provide a zoom system with low cost and high-definition imaging magnification while ensuring 3X magnification.

[0004] To achieve the above-mentioned object, the present invention provides a zoom system, wherein the zoom system includes a housing and a plurality of lens groups, wherein the plurality of lens groups form an optical axis within the housing, and the plurality of lens groups include:

[0005] A first lens group is fixed in the housing, and the first lens group has positive optical power;

[0006] a second lens group having negative optical power, the second lens group being movably disposed in the housing along an extension direction of the optical axis so as to have a movable range between being close to the object side or close to the image side;

[0007] A third lens group is fixed in the housing, and the third lens group has positive optical power;

[0008] a fourth lens group having positive refractive power, the fourth lens group being movably disposed in the housing along an extension direction of the optical axis so as to have a movable range between being close to the object side or close to the image side; and

[0009] Image plane;

[0010] Among them, by controlling the refractive index, Abbe number, curvature and core thickness of each lens in the first lens group, the second lens group, the third lens group and the fourth lens group arranged in sequence from the object side to the image side, the zoom system can achieve a magnification of 3x when the total optical length of the zoom system is controlled to be less than 53 mm.

[0011] Optionally, the focal length of the first lens group is , the focal length of the second lens group is , the focal length of the third lens group is , the focal length of the fourth lens group is ,in, , , .

[0012] Optionally, the effective focal length of the zoom system is f, 10mm≤f≤30mm.

[0013] Optionally, the distance between the first lens group and the second lens group at the wide-angle end is , the distance between the first lens group and the second lens group at the telephoto end is , the distance between the second lens group and the third lens group at the wide-angle end is , the distance between the second lens group and the third lens group at the telephoto end is The distance between the third lens group and the fourth lens group at the wide-angle end is The distance between the third lens group and the fourth lens group at the telephoto end is , the distance between the fourth lens group and the image plane at the wide-angle end is , the distance between the fourth lens group and the image plane at the telephoto end is ,in, , , , .

[0014] Optionally, the first lens group includes a first lens with negative optical power and a second lens with positive optical power, which are arranged in sequence from the object side to the image side;

[0015] The second lens group includes a third lens with negative optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power, which are arranged in sequence from the object side to the image side;

[0016] The third lens group includes a sixth lens with positive optical power, a seventh lens with positive optical power, and an eighth lens with negative optical power, which are arranged in sequence from the object side to the image side;

[0017] The fourth lens group includes, arranged in sequence from the object side to the image side, a ninth lens with positive optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, a twelfth lens with negative optical power, and a thirteenth lens with negative optical power.

[0018] Optionally, the first lens, the second lens, the third lens, and the ninth lens are all glass spherical lenses.

[0019] Optionally, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the tenth lens, the eleventh lens, the twelfth lens, and the thirteenth lens are all plastic aspheric lenses.

[0020] Optionally, an aperture is provided between the second lens group and the third lens group, and the aperture is fixed in the housing.

[0021] Optionally, the zoom system further includes a photosensitive chip, wherein the photosensitive chip is provided on a side of the fourth lens group facing the image side, and the side of the photosensitive chip facing the fourth lens group forms the image plane; and / or,

[0022] A filter is provided between the photosensitive chip and the fourth lens group.

[0023] The present invention also provides a camera device, which includes the zoom system mentioned above.

[0024] In the technical solution provided by the present invention, the second lens group and the fourth lens group are movably arranged along the extension direction of the optical axis respectively, and the second lens group moves cooperatively along the optical axis so that the zoom system can zoom from the wide-angle end to the telephoto end, and the fourth lens group is driven by an external force to move and focus along the optical axis corresponding to the position, imaging wavelength and imaging object distance of the second lens group, so that the zoom system can maintain clear imaging on the image plane during the zooming process. Through the reasonable arrangement of the four lens groups and the conditional restrictions on the refractive index, Abbe number, curvature and core thickness of each lens in the first lens group, the second lens group, the third lens group and the fourth lens group, the zoom system can achieve clear imaging when the zoom system achieves a 3x magnification, providing a zoom system with low cost and high-definition imaging magnification while ensuring 3X magnification. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0026] Figure 1 This is a schematic structural diagram of the zoom system provided by the present invention at the wide-angle end;

[0027] Figure 2 This is a schematic structural diagram of the zoom system main body provided by the present invention at the telephoto end;

[0028] Figure 3 for Figure 1 MTF curve diagram of the wide-angle end of the medium zoom system body;

[0029] Figure 4 for Figure 1 MTF curve graph for the middle end of the medium zoom system body;

[0030] Figure 5 for Figure 1 MTF curve diagram of the telephoto end of the medium zoom system body.

[0031] Description of Figure Numbers:

[0032]

[0033] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] 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 for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. 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 mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] Currently, security systems generally have the following shortcomings: high lens cost and poor imaging quality. In order to solve the above problems, the present invention provides a low-cost high-definition imaging lens.

[0038] In order to solve the above problems, the present invention provides a zoom system. Figure 1 and Figure 2 This is a specific embodiment of the zoom system provided by the present invention.

[0039] See also Figure 1 The zoom system includes a housing and a plurality of lens groups. An optical axis is formed between the plurality of lens groups in the housing. The plurality of lens groups include a first lens group 100, a second lens group 200, a third lens group 300, a fourth lens group 400 and an image plane. The first lens group 100 is fixed in the housing. The first lens group 100 has positive optical power; the second lens group 200 has negative optical power. The second lens group 200 is movably provided in the housing along the extension direction of the optical axis to have a movable stroke between close to the object side and close to the image side; the third lens group 300 is fixed in Inside the housing, the third lens group 300 has positive optical power; the fourth lens group 400 has positive optical power, and the fourth lens group 400 is movably disposed in the housing along the extension direction of the optical axis so as to have a movable range between close to the object side and close to the image side. Particularly, by controlling the refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group 100, the second lens group 200, the third lens group 300, and the fourth lens group 400, which are arranged sequentially from the object side to the image side, the zoom system can achieve a magnification of 3x when the total optical length of the zoom system is controlled to be less than 53 mm.

[0040] In the technical solution provided by the present invention, the second lens group 200 and the fourth lens group 400 are respectively movably arranged along the extension direction of the optical axis. The second lens group 200 moves in coordination along the optical axis to enable the zoom system to zoom from the wide-angle end to the telephoto end. The fourth lens group 400 is driven by an external force to move and focus along the optical axis corresponding to the position, imaging wavelength, and imaging object distance of the second lens group 200, so that the zoom system maintains clear image on the image plane during the zooming process. Through the reasonable arrangement of the four lens groups and the conditional restrictions on the refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group 100, the second lens group 200, the third lens group 300, and the fourth lens group 400, the zoom system can achieve clear imaging when the zoom system achieves a 3x magnification. This provides a zoom system with low cost and high-definition imaging magnification while ensuring 3x magnification.

[0041] It should be noted that both the second lens group 200 and the third lens group 300 can be driven by an external force to move along the optical axis, wherein the external force can be driven by a driving motor or manually adjusted without limitation.

[0042] Specifically, in order to enable the spherical lenses to cooperate with each other to achieve the desired effect, in this embodiment, the focal length of the first lens group 100 is , the focal length of the second lens group 200 is , the focal length of the third lens group 300 is , and the focal length of the fourth lens group 400 is , where, , , By setting the focal length setting ratio, the minimum focal length of the zoom system can be controlled to reach 10 mm, and the maximum focal length of the zoom system can be controlled to reach 30 mm, achieving a magnification of 3x.

[0043] Specifically, in this embodiment, when the second lens group 200 moves along the optical axis toward the object side and the fourth lens group 400 moves along the optical axis toward the image side, zooming from the telephoto end to the wide-angle end is achieved. When the second lens group 200 moves along the optical axis toward the image side and the fourth lens group 400 moves along the optical axis toward the object side, zooming from the wide-angle end to the telephoto end is achieved. The distance between the first lens group 100 and the second lens group 200 at the wide-angle end is , and the distance between the first lens group 100 and the second lens group 200 at the telephoto end is The distance between the second lens group 200 and the third lens group 300 at the wide-angle end is , the distance between the second lens group 200 and the third lens group 300 at the telephoto end is , the distance between the third lens group 300 and the fourth lens group 400 at the wide-angle end is , the distance between the third lens group 300 and the fourth lens group 400 at the telephoto end is , the distance between the fourth lens group 400 and the image plane at the wide-angle end is , and the distance between the fourth lens group 400 and the image plane at the telephoto end is , wherein, , , , This configuration enables the zoom system to have an operating F-number within the range of 1.75-1.8 from the wide-angle end to the telephoto end.

[0044] Specifically, in this embodiment, the first lens group 100 includes, arranged sequentially from the object side to the image side, a first lens 1 with negative optical power and a second lens 2 with positive optical power; the second lens group 200 includes, arranged sequentially from the object side to the image side, a third lens 3 with negative optical power, a fourth lens 4 with negative optical power, and a fifth lens 5 with positive optical power; the third lens group 300 includes, arranged sequentially from the object side to the image side, a sixth lens 6 with positive optical power, a seventh lens 7 with positive optical power, and an eighth lens 8 with negative optical power; and the fourth lens group 400 includes, arranged sequentially from the object side to the image side, a ninth lens 9 with positive optical power, a tenth lens 10 with negative optical power, an eleventh lens 11 with positive optical power, a twelfth lens 12 with negative optical power, and a thirteenth lens 13 with negative optical power. It should be noted that optical power is equal to the difference between the image-side and object-side beam convergence, and it represents the ability of an optical system to deflect light. By rationally distributing the optical power of the lenses, adjusting the glass shape and material combination, effectively eliminating chromatic aberration and secondary spectrum, the spherical aberration, coma, astigmatism, etc. on each lens are compensated and offset to achieve a clear imaging effect.

[0045] Specifically, considering the impact of temperature fluctuations, glass lenses are characterized by high hardness, strong wear resistance, and long service life. Therefore, in this embodiment, the first lens 1, the second lens 2, the third lens 3, and the ninth lens 9 are all glass spherical lenses. Therefore, glass lenses can effectively resist thermal deformation, maintain high lens precision over a long period of time, ensure image quality and reliability, reduce assembly sensitivity, and improve product yield.

[0046] Specifically, in this embodiment, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the tenth lens 10, the eleventh lens 11, the twelfth lens 12, and the thirteenth lens 13 are all plastic aspheric lenses. The use of plastic aspheric lenses effectively controls costs and effectively corrects lens chromatic aberration, simultaneously correcting spherical aberration and sine aberration at high magnification positions while ensuring that purple fringing is controlled.

[0047] Furthermore, to improve imaging quality, in this embodiment, an aperture 500 is provided between the second lens group 200 and the third lens group 300. The aperture 500 is fixedly mounted within the housing. The aperture 500 limits the aperture of the on-axis light beam and blocks some light during zooming, thereby reducing light spots, increasing image contrast, and improving image quality.

[0048] Specifically, in this embodiment, the zoom system also includes a photosensitive chip 600, which is arranged on the side of the fourth lens group 400 facing the image side, and the photosensitive chip 600 forms the image plane on the side facing the fourth lens group 400, so as to receive the object image on the image side of the image plane of the photosensitive chip 600, and process the received object image through the photosensitive chip 600.

[0049] Furthermore, a filter is positioned between the photosensitive chip 600 and the fourth lens group 400. This filter effectively filters out stray light in non-operating wavelengths, reducing optical noise and simplifying subsequent photoelectric module processing. The filter can also be used to adjust the color saturation of the final image.

[0050] Specifically, the image plane can be understood as the surface of the photosensitive chip 600 facing the object side, that is, it can be the surface of a camera element such as a CCD or CMOS. It can be understood that the light carrying information of the object can pass through the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, the twelfth lens 12, the thirteenth lens 13, and the filter in sequence and finally form an image on the image plane.

[0051] Please note that Figure 2 In a specific embodiment, the basic parameter table of the zoom system is shown in Table 1, where the units of curvature radius and thickness are both millimeters (mm).

[0052] Table 1

[0053]

[0054] In Table 1, S1 to S33 represent the surface numbers of the optical elements, R represents the radius of curvature of the optical element, D represents the thickness of the optical element or the air gap, Nd represents the d-light refractive index of the optical material used, and Vd represents the d-light Abbe number of the optical material used. Specifically, the aperture surface STOP, the first lens light incident surface S1, the first lens light exit surface S2, the second lens light incident surface S2, the second lens light exit surface S3, the third lens light incident surface S4, the third lens light exit surface S5, the fourth lens light incident surface S6, the fourth lens light exit surface S7, the fifth lens light incident surface S8, the fifth lens light exit surface S9, the sixth lens light incident surface S11, the sixth lens light exit surface S12, the seventh lens light incident surface S13, the seventh lens light exit surface S14, the eighth lens light incident surface S15, the eighth lens light exit surface S16, the ninth lens light incident surface S17, the ninth lens light exit surface S18, the tenth lens light incident surface S19, the tenth lens light exit surface S20, the eleventh lens light incident surface S21, the eleventh lens light exit surface S22, the twelfth lens light incident surface S23, the twelfth lens light exit surface S24, the thirteenth lens light incident surface S25, and the thirteenth lens light exit surface S26.

[0055] Among them, the distance between each lens group at the wide-angle end and the telephoto end is shown in Table 2:

[0056] Table 2

[0057]

[0058] In Table 2, D1 represents the variable distance between the first lens group 100 and the second lens group 2, D2 represents the variable distance between the second lens group 2 and the aperture stop, D3 represents the variable distance between the aperture stop and the third lens group 300, and D4 represents the variable distance between the third lens group 300 and the fourth lens group 400.

[0059] Specifically, since the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the tenth lens 10, the eleventh lens 11, the twelfth lens 12, and the thirteenth lens 13 are all plastic aspherical lenses, the characteristic of aspherical lenses is that the curvature changes continuously from the center of the lens to the periphery. Unlike spherical lenses with a constant curvature from the center of the lens to the periphery, aspherical lenses have better curvature radius characteristics and have the advantages of improving distortion aberration and improving astigmatism aberration. After using aspherical lenses, aberrations occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens. The use of glass lenses can reduce the impact of temperature on the optical performance of the lens.

[0060] Furthermore, in this embodiment, the aspheric surface shape of the aspheric lens satisfies the following conditions:

[0061]

[0062] Among them, z represents the axial sagittal height of the aspheric surface in the Z direction; y represents the height of the aspheric surface; c represents the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the conic quadratic coefficient (when the k coefficient is less than -1, the surface curve is a hyperbola; when the k coefficient is equal to -1, it is a parabola; when the k coefficient is between -1 and 0, it is an ellipse; when the k coefficient is equal to 0, it is a circle; when the k coefficient is greater than 0, it is an oblate circle); a1, a2, a3, and a4 are high-order aspheric coefficients (please refer to Table 3 below). The above parameters can be used to set the shape and size of the lens object side and image side aspheric surfaces.

[0063] Table 3 Conic coefficient and aspheric coefficient corresponding to aspheric lenses:

[0064]

[0065] Figure 3 The MTF (Modulation Transfer Function) curve of the zoom system body at the wide-angle end is displayed, where the horizontal axis of the curve represents the image height (the distance from the imaging center in mm) and the vertical axis represents the contrast value (the value is 1).

[0066] Figure 4 An MTF (Modulation Transfer Function) graph of the middle end of the zoom system body is displayed, where the horizontal axis represents image height (distance from the imaging center in mm) and the vertical axis represents contrast value (value is 1).

[0067] Figure 5 The MTF (Modulation Transfer Function) curve graph of the zoom system body at the telephoto end is displayed, where the horizontal axis of the curve graph represents the image height (distance from the imaging center in mm) and the vertical axis represents the contrast value (value is 1).

[0068] As can be seen from the above figures, the zoom system in this embodiment can achieve good correction of spherical aberration, field curvature and distortion at the intermediate end, wide-angle end and telephoto end respectively.

[0069] In addition, the present invention also provides a camera device, which can be outdoor monitoring, indoor monitoring, etc. The camera device includes the zoom system described in the above technical solution. Since the camera device includes the zoom system, the specific structure of the zoom system refers to the above embodiment. Since the zoom system of this camera device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A zoom system, characterized in that: The invention comprises a housing and a plurality of lens groups, wherein the plurality of lens groups form an optical axis in the housing, and the plurality of lens groups include: A first lens group is fixed in the housing, and the first lens group has positive optical power; a second lens group having negative optical power, the second lens group being movably disposed in the housing along an extension direction of the optical axis so as to have a movable range between being close to the object side or close to the image side; A third lens group is fixed in the housing, and the third lens group has positive optical power; a fourth lens group having positive refractive power, the fourth lens group being movably disposed in the housing along an extension direction of the optical axis so as to have a movable range between being close to the object side or close to the image side; and Image plane; Wherein, by controlling the refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group, the second lens group, the third lens group, and the fourth lens group, which are arranged sequentially from the object side to the image side, a magnification of the zoom system of 3x can be achieved when the total optical length of the zoom system is controlled to be less than 53 mm; The focal length of the first lens group is , the focal length of the second lens group is , the focal length of the third lens group is , the focal length of the fourth lens group is ,in, , , ; The first lens group includes a first lens with negative optical power and a second lens with positive optical power, which are arranged in sequence from the object side to the image side; The second lens group includes a third lens with negative optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power, which are arranged in sequence from the object side to the image side; The third lens group includes a sixth lens with positive optical power, a seventh lens with positive optical power, and an eighth lens with negative optical power, which are arranged in sequence from the object side to the image side; The fourth lens group includes, arranged in sequence from the object side to the image side, a ninth lens with positive optical power, a tenth lens with negative optical power, an eleventh lens with positive optical power, a twelfth lens with negative optical power, and a thirteenth lens with negative optical power.

2. The zoom system according to claim 1, wherein: The effective focal length of the zoom system is f, 10mm≤f≤30mm.

3. The zoom system according to claim 1, wherein: The distance between the first lens group and the second lens group at the wide-angle end is , the distance between the first lens group and the second lens group at the telephoto end is , the distance between the second lens group and the third lens group at the wide-angle end is , the distance between the second lens group and the third lens group at the telephoto end is , the distance between the third lens group and the fourth lens group at the wide-angle end is , the distance between the third lens group and the fourth lens group at the telephoto end is , the distance between the fourth lens group and the image plane at the wide-angle end is , the distance between the fourth lens group and the image plane at the telephoto end is ,in, , , , .

4. The zoom system according to claim 1, wherein: The first lens, the second lens, the third lens, and the ninth lens are all glass spherical lenses.

5. The zoom system according to claim 1, wherein: The fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the tenth lens, the eleventh lens, the twelfth lens, and the thirteenth lens are all plastic aspherical lenses.

6. The zoom system according to claim 1, wherein: An aperture is provided between the second lens group and the third lens group, and the aperture is fixed in the housing.

7. The zoom system according to claim 1, wherein: The zoom system further includes a photosensitive chip, which is disposed on a side of the fourth lens group facing the image side, and the side of the photosensitive chip facing the fourth lens group forms the image plane; and / or, A filter is provided between the photosensitive chip and the fourth lens group.

8. A camera device, characterized in that: Comprising a zoom system as claimed in any one of claims 1 to 7.

Images