Zoom optical system and surveillance camera equipment

Abstract

The present invention discloses a zoom optical system and a surveillance camera device. The zoom optical system includes a plurality of lens groups arranged sequentially from the object side to the image side, wherein the plurality of lens groups form an optical axis. The plurality of lens groups include a first lens group and a second lens group, wherein the first lens group and the second lens group are respectively movable along the extension direction of the optical axis. Image plane compensation is achieved by offsetting the change in the conjugate distance of the first lens group with the change in the conjugate distance after longitudinal magnification of the second lens group. Furthermore, by controlling the material, refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group and the second lens group, the zoom optical system can achieve a magnification of 4x when the total optical length is controlled to be less than 45 mm, thereby solving the problem of large size and low magnification of existing zoom optical systems.

Description

Technical Field

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

[0002] Zoom optical systems used for surveillance are generally large in size, have low magnification for the same overall length, cannot guarantee infrared confocality at every magnification during zooming, and exhibit significant degradation in resolution in high and low temperature environments (70°C and -40°C). Currently, most lenses on the market are large in size and have low magnification, hindering their widespread adoption in specific environments. Summary of the Invention

[0003] The main purpose of the present invention is to provide a zoom optical system and a monitoring camera device, aiming to solve the problem that the existing zoom optical system is large in size and has a small magnification.

[0004] To achieve the above objectives, the present invention provides a zoom optical system, wherein the zoom optical system includes a plurality of lens groups arranged sequentially from the object side to the image side, wherein the plurality of lens groups form an optical axis, wherein the plurality of lens groups include:

[0005] a first lens group including a first lens, a second lens, a third lens, and a fourth lens arranged in order from the object side to the image side; and

[0006] The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in order from the object side to the image side.

[0007] The first lens group and the second lens group are movably arranged along the extension direction of the optical axis respectively. By controlling the material, refractive index, Abbe number, curvature and core thickness of each lens in the first lens group and the second lens group, the magnification of the zoom optical system can be achieved to be 4x when the total optical length of the zoom optical system is controlled to be less than 45 mm.

[0008] Optionally, the first lens, the third lens, the fourth lens, the fifth lens, the seventh lens and the tenth lens are made of glass.

[0009] Optionally, the second lens, the sixth lens, the eighth lens, the ninth lens and the eleventh lens are made of plastic.

[0010] Optionally, the first lens, the third lens, the fourth lens, the seventh lens and the tenth lens are all spherical lenses.

[0011] Optionally, the second lens, the fifth lens, the sixth lens, the eighth lens, the ninth lens and the eleventh lens are all aspherical lenses.

[0012] Optionally, the optical power of the first lens group is negative, and the optical power of the second lens group is positive.

[0013] Optionally, the optical focal power of the fifth lens is positive, the optical focal power of the sixth lens is negative or positive, the optical focal power of the seventh lens is positive, the optical focal power of the eighth lens is negative, the optical focal power of the ninth lens is positive, the optical focal power of the tenth lens is negative, and the optical focal power of the eleventh lens is negative or positive.

[0014] Optionally, the third lens and the fourth lens are cemented together.

[0015] Optionally, an aperture stop is provided between the first lens group and the second lens group, a distance between a side of the first lens group facing the image side and the aperture stop is L1, wherein 0.83 mm ≤ L1 ≤ 10.02 mm, and a distance between a side of the second lens group facing the object side and the aperture stop is L2, wherein 0.35 mm ≤ L2 ≤ 8.894 mm; and / or,

[0016] The optical lens system further includes a photosensitive chip, wherein the photosensitive chip is disposed on a side of the second lens group facing the image side, and a photosensitive surface of the photosensitive chip is disposed toward the second lens group; and / or,

[0017] A filter is provided between the photosensitive chip and the second lens group.

[0018] The present invention further provides a surveillance camera device, comprising an optical lens system, wherein the optical lens system comprises a plurality of lens groups arranged sequentially from the object side to the image side, wherein an optical axis is formed between the plurality of lens groups, wherein the plurality of lens groups comprise:

[0019] a first lens group including a first lens, a second lens, a third lens, and a fourth lens arranged in order from the object side to the image side; and

[0020] The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in order from the object side to the image side.

[0021] The first lens group and the second lens group are movably arranged along the extension direction of the optical axis respectively. By controlling the material, refractive index, Abbe number, curvature and core thickness of each lens in the first lens group and the second lens group, the magnification of the zoom optical system can be achieved to be 4x when the total optical length of the zoom optical system is controlled to be less than 45 mm.

[0022] In the technical solution provided by the present invention, the first lens group and the second lens group are respectively movably arranged along the extension direction of the optical axis. Image plane compensation is achieved by offsetting the change in the conjugate distance of the first lens group and the change in the conjugate distance after longitudinal magnification of the second lens group. In addition, by controlling the material, refractive index, Abbe number, curvature and core thickness of each lens in the first lens group and the second lens group, the magnification of the zoom optical system can be achieved to 4x when the total optical length of the zoom optical system is controlled to be less than 45 mm, thereby solving the problem of large size and small magnification of existing zoom optical systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] Figure 1 A three-dimensional schematic diagram of an embodiment of a zoom optical system provided by the present invention.

[0025] Description of Figure Numbers:

[0026] Label name Label name 1000 Zoom optical system 7 Seventh lens 100 First lens group 8 Eighth lens 1 First lens 9 Ninth lens 2 Second lens 10 Tenth lens 3 The third lens 11 Eleventh lens 4 Fourth lens 30 aperture 200 Second lens group 40 Photosensitive chip 5 Fifth lens 50 Filters 6 Sixth lens

[0027] 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

[0028] 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.

[0029] 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 various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0030] 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.

[0031] Currently, zoom optical systems used in surveillance systems are generally large in size, have low magnification for the same overall length, cannot guarantee infrared confocality at every magnification during zooming, and exhibit a significant drop in resolution in high and low temperature environments (70°C and -40°C). Most lenses currently on the market are large in size and have low magnification, hindering their widespread adoption in specific environments.

[0032] In order to solve the above problems, the present invention provides a zoom optical system 1000. Figure 1 This is a specific embodiment of the zoom optical system 1000 provided by the present invention.

[0033] See also Figure 1 The zoom optical system 1000 includes a plurality of lens groups arranged in sequence from the object side to the image side, and an optical axis is formed between the plurality of lens groups. The plurality of lens groups include a first lens group 100 and a second lens group 200. The first lens group 100 includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 arranged in sequence from the object side to the image side; the second lens group 200 includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, and an eleventh lens 11 arranged in sequence from the object side to the image side. The first lens group 100 and the second lens group 200 are respectively movably arranged along the extension direction of the optical axis. By controlling the material, refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group 100 and the second lens group 200, the zoom optical system 1000 can achieve a magnification of 4x when the total optical length of the zoom optical system 1000 is controlled to be less than 45 mm.

[0034] In the technical solution provided by the present invention, the first lens group 100 and the second lens group 200 are respectively movably arranged along the extension direction of the optical axis. Image plane compensation is achieved by offsetting the change in the conjugate distance of the first lens group 100 with the change in the conjugate distance after longitudinal magnification of the second lens group 200. In addition, by adjusting the material, refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group 100 and the second lens group 200, by rationally distributing the lens focal length, adjusting the glass shape and material combination, effective achromatism and secondary spectrum are eliminated, so that spherical aberration, coma, and astigmatism on each lens are mutually compensated to achieve a clear imaging effect. When the total optical length of the zoom optical system 1000 is controlled to be less than 45 mm, the zoom optical system 1000 can achieve a magnification of 4x and achieve confocality in the visible band and infrared band, ensuring clear imaging in the visible band and infrared band at all magnifications, thereby solving the problem of large size and small magnification of the existing zoom optical system 1000.

[0035] Specifically, considering the impact of temperature changes, glass lenses are characterized by high hardness, strong wear resistance, and long service life. Furthermore, all-glass lenses are chemically stable and are not easily affected by thermal expansion and contraction, resulting in focus shifting, nor are they easily corroded. All-glass lenses can effectively resist thermal deformation and maintain high lens precision for a long time. Therefore, in this embodiment, the first lens 1, the third lens 3, the fourth lens 4, the fifth lens 5, the seventh lens 7, and the tenth lens 10 are made of glass.

[0036] Specifically, to reduce the weight of the zoom optical system 1000 and lower control costs, in this embodiment, the second lens 2, the sixth lens 6, the eighth lens 8, the ninth lens 9, and the eleventh lens 11 are made of plastic. This configuration not only provides the zoom optical system 1000 with excellent impact resistance, weathering resistance, and UV radiation resistance.

[0037] By combining glass and plastic materials, the zoom optical system 1000 can be used in high and low temperature conditions, ensuring that the lens still has sufficient clarity under the focusing condition at normal temperature of 20°C and in high and low temperature environments (high temperature of 70°C and low temperature of -40°C).

[0038] Specifically, in this embodiment, the first lens 1, the third lens 3, the fourth lens 4, the seventh lens 7, and the tenth lens 10 are all spherical lenses. Because the reflection of spherical lenses obeys the law of reflection of light, converging or diverging the light, aspherical lenses can correct spherical aberration.

[0039] Specifically, in this embodiment, the second lens 2, the fifth lens 5, the sixth lens 6, the eighth lens 8, the ninth lens 9, and the eleventh lens 11 are all aspherical lenses. The use of aspherical lenses can correct for spherical aberration, coma, astigmatism, and distortion caused by the image of light transmitted by a spherical lens. It also reduces the deflection angle of light, resulting in smoother light flow in the system, lessens the sensitivity of lens assembly tolerances, and resolves issues such as field of view distortion. Furthermore, aspherical lenses make lenses lighter, thinner, and flatter, while still maintaining excellent impact resistance.

[0040] Furthermore, during the optical design process, lens groups are grouped according to their functions and tasks. The first lens group 100 has a negative optical power; the second lens group 200 has a positive optical power. The fifth lens group 5 has a positive optical power, the sixth lens group 6 has a negative or positive optical power, the seventh lens group 7 has a positive optical power, the eighth lens group 8 has a negative optical power, the ninth lens group 9 has a positive optical power, the tenth lens group 10 has a negative optical power, and the eleventh lens group 11 has a negative or positive optical power. This arrangement achieves optimal correction of high-order aberrations and chromatic aberrations, while also providing vignetting. This eliminates peripheral stray light without compromising illumination, ensuring consistent resolution at the center and edges of the image plane.

[0041] The surface shape of any of the above lenses needs to satisfy the following formula:

[0042]

[0043] Wherein, c corresponds to the reciprocal of the radius R, y is the radial coordinate, k is the conic quadratic curve coefficient, and a1 to a8 are the coefficients corresponding to each radial coordinate.

[0044] It should be noted that the basic parameters of the optical lens system in this embodiment are shown in Table 1, where the units of curvature radius and thickness are both millimeters (mm).

[0045] Table 1

[0046]

[0047]

[0048] Among them, the aspheric coefficients of each surface are shown in Table 2:

[0049] Table 2

[0050]

[0051]

[0052] Furthermore, to improve the optical system's image quality, reduce light energy loss, increase image clarity, protect the scaled surface, and further optimize the manufacturing process to meet design requirements, in this embodiment, the third lens 3 and the fourth lens 4 are cemented together. The rational use of the cemented components, the appropriate distribution of optical power, and the combination of the thermal parameters of the glass material effectively correct aberrations and achieve athermalization at high and low temperatures. Chromatic aberration is also effectively reduced, achieving confocal imaging in the visible and near-infrared bands, while also achieving clear, simultaneous imaging, meeting the requirements of both daytime and nighttime use.

[0053] Furthermore, to improve imaging quality, in this embodiment, an aperture 30 is provided between the first lens group 100 and the second lens group 200. The aperture 30 limits the aperture of the on-axis light beam and blocks some light during the zooming process, thereby reducing light spots, improving image contrast, and helping to improve image quality.

[0054] Specifically, to specifically control the range of motion of the first lens group 100 and the second lens group 200, in this embodiment, the distance between the image-side side of the first lens group 100 and the aperture 30 is L1, where 0.83 mm ≤ L1 ≤ 10.02 mm, and the distance between the object-side side of the second lens group 200 and the aperture 30 is L2, where 0.35 mm ≤ L2 ≤ 8.894 mm. It should be noted that the above two related technical features can be provided simultaneously or alternatively.

[0055] Specifically, in this embodiment, the optical lens system also includes a photosensitive chip 40, which is arranged on the side of the second lens group 200 facing the image side, and the photosensitive surface of the photosensitive chip 40 is arranged toward the second lens group 200, so as to receive the object image on the image side and process the received object image through the photosensitive chip 40.

[0056] Furthermore, a filter 50 is disposed between the photosensitive chip 40 and the second lens assembly 200. This filter 50 effectively filters out stray light in non-operating wavelengths, reducing optical noise and simplifying subsequent photoelectric module processing. The filter 50 can also be used to adjust the color saturation of the final image.

[0057] In the zoom optical system 1000, the third lens 3 and the fourth lens 4 are bonded together to effectively correct lens chromatic aberration, achieving infrared confocality while controlling lens purple fringing. The second lens 2 is a meniscus lens, and its plastic aspheric shape reduces lens distortion. Furthermore, in combination with the first lens 1, it creates a bonding-like effect, further correcting chromatic aberration, spherical aberration, and sinusoidal aberration at high magnifications. The second lens group 200 utilizes a glass aspheric lens after the aperture 30 to correct aberrations in the light exiting the aperture 30, ensuring stable image resolution at high and low temperatures. The fifth lens 5 is a meniscus lens, further reducing distortion. Combined with the subsequent lens arrangement, this creates a perfect, bonded structure (i.e., the focal powers of the sixth lens 6 through the eleventh lens 11 after the aperture 30 are arranged in a series of negative, positive, negative, positive, negative, and positive lenses), achieving optimal correction of high-order aberrations and chromatic aberrations. At the same time, each lens is set with vignetting to block peripheral stray light without affecting the illumination, so that the center and edge of the image plane can maintain the same resolution requirements.

[0058] In this way, in order to achieve clear image resolution in high and low temperature environments (high temperature 70℃, low temperature -40℃), the system uses plastic materials with small differences in refractive index corresponding to high and low temperatures. At the same time, the changes in the refractive index and Abbe number of various lens materials at high and low temperatures are considered to match the changes in surface shape and air gap, ensuring the positive and negative matching of the changes in the amounts of each factor in high and low temperature environments, thereby achieving synchronization and clarity of the image surface in high and low temperature environments.

[0059] The present invention provides a surveillance camera device, comprising the above-mentioned optical lens system. Since the surveillance camera device comprises the optical lens system, the specific structure of the optical lens system is referred to the above-mentioned embodiments. Since the optical lens system of the surveillance camera device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be described in detail here.

[0060] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present description and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A zoom optical system, characterized in that: The invention comprises two lens groups arranged in sequence from the object side to the image side, wherein an optical axis is formed between the two lens groups, wherein the two lens groups are configured as follows: a first lens group comprising a first lens, a second lens, a third lens, and a fourth lens arranged in order from the object side to the image side; and A second lens group is configured to include a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in order from the object side to the image side; The first lens group and the second lens group are movably arranged along the extension direction of the optical axis. By adjusting the material, refractive index, Abbe number, curvature, and core thickness of each lens in the first lens group and the second lens group, a magnification of 4x can be achieved when the total optical length of the zoom optical system is controlled to be less than 45 mm. The optical power of the first lens is negative, the optical power of the second lens is positive, the optical power of the third lens is negative, and the optical power of the fourth lens is positive; The fifth lens has a positive optical power, the sixth lens has a negative optical power, the seventh lens has a positive optical power, the eighth lens has a negative optical power, the ninth lens has a positive optical power, the tenth lens has a negative optical power, and the eleventh lens has a positive optical power; The third lens and the fourth lens are cemented together.

2. The zoom optical system according to claim 1, wherein: The first lens, the third lens, the fourth lens, the fifth lens, the seventh lens, and the tenth lens are made of glass.

3. The zoom optical system according to claim 1, wherein: The second lens, the sixth lens, the eighth lens, the ninth lens and the eleventh lens are made of plastic.

4. The zoom optical system according to claim 1, wherein: The first lens, the third lens, the fourth lens, the seventh lens and the tenth lens are all spherical lenses.

5. The zoom optical system according to claim 1, wherein: The second lens, the fifth lens, the sixth lens, the eighth lens, the ninth lens and the eleventh lens are all aspherical lenses.

6. The zoom optical system according to claim 1, wherein: The first lens group has negative refractive power, and the second lens group has positive refractive power.

7. The zoom optical system according to claim 1, wherein: An aperture stop is provided between the first lens group and the second lens group, a distance L1 between a side of the first lens group facing the image side and the aperture stop is 0.83 mm ≤ L1 ≤ 10.02 mm, and a distance L2 between a side of the second lens group facing the object side and the aperture stop is 0.35 mm ≤ L2 ≤ 8.894 mm; and / or The zoom optical system further includes a photosensitive chip, wherein the photosensitive chip is disposed on a side of the second lens group facing the image side, and a photosensitive surface of the photosensitive chip is disposed toward the second lens group; and / or, A filter is provided between the photosensitive chip and the second lens group.

8. A surveillance camera device, characterized in that: Comprising the zoom optical system according to any one of claims 1 to 7.

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