Lens assembly, cooking device

Abstract

The application relates to the optical technical field and discloses a lens assembly, which is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens along the direction of an optical axis from an object side to an image side; the object side surface of the first lens is a convex surface, and the image side surface is a concave surface; the object side surface of the second lens is a convex surface, and the image side surface is a concave surface; the object side surface of the third lens is a concave surface, and the image side surface is a convex surface; the object side surface of the fourth lens is a concave surface, and the image side surface is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface is a concave surface; the object side surface of the sixth lens is a convex surface, and the image side surface is a convex surface; and the object side surface of the seventh lens is a concave surface, and the image side surface is a convex surface; wherein the outer diameter of the lenses presents a decreasing trend from the first lens to the seventh lens. By arranging the seven lenses in the lens assembly, the lens assembly can clearly image under superhigh temperature. The application further discloses a cooking device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lenses, for example to a lens assembly and a cooking device. BACKGROUND

[0002] At present, some cooking devices usually need to work in an ultra-high temperature environment, for example, an oven or an air fryer, which has a cooking temperature usually above 300 degrees Celsius to meet people's cooking needs of baking.

[0003] Some users like to take pictures of the cooking process of food in a high-temperature environment or observe the surface morphology of things during baking. In the related art, the top surface of an oven is provided with a camera, and the lens of the camera includes, along the optical axis from the object side to the imaging surface, a first lens with positive refractive power, whose object side is convex and image side is concave; a second lens with positive refractive power, whose object side is concave and image side is convex; and a third lens with negative refractive power, whose object side is convex at the near optical axis and image side is concave at the near optical axis.

[0004] In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art:

[0005] In the related art, in an ultra-high temperature environment, for example, above 300 degrees Celsius, there are certain difficulties in image acquisition, mainly that the light transmittance and light collection amount cannot be well guaranteed in an ultra-high temperature fog environment, and the lens cannot balance the ultra-high temperature resistance and clear imaging. SUMMARY

[0006] To have a basic understanding of some aspects of the disclosed embodiments, a brief overview is given below. The overview is not an overall description of the application, nor is it intended to identify key / important elements or delineate the scope of the embodiments. It is intended to serve as an introduction to the detailed description below.

[0007] The embodiments of the present disclosure provide a lens assembly and a cooking device, which can make the lens assembly clearly image in an ultra-high temperature environment by arranging seven lenses in the lens assembly, thereby meeting the shooting needs of users.

[0008] In some embodiments, the lens assembly along the direction of the optical axis from the object side to the image side is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, the object side surface of the first lens is convex, and the image side surface is concave, the object side surface of the second lens is convex, and the image side surface is concave; the object side surface of the third lens is concave, and the image side surface is convex, the object side surface of the fourth lens is concave, and the image side surface is convex, the object side surface of the fifth lens is convex, and the image side surface is concave, the object side surface of the sixth lens is convex, and the image side surface is convex, the object side surface of the seventh lens is concave, and the image side surface is convex; wherein the outer diameter of the lens presents a decreasing trend from the first lens to the seventh lens, the air gap between the edge positions of the first lens and the second lens is 0 mm, the air gap between the edge positions of the second lens and the third lens is 0 mm, and the air gap between the edge positions of the sixth lens and the seventh lens is 0 mm.

[0009] Optionally, the outer diameter of the second lens is equal to the outer diameter of the third lens, and equal to the outer diameter of the fourth lens; the outer diameter of the fifth lens is equal to the outer diameter of the sixth lens, and equal to the outer diameter of the seventh lens.

[0010] Optionally, the air gap between the edge positions of the third lens and the fourth lens is greater than or equal to 0.7 mm and less than or equal to 1.1 mm, the air gap between the edge positions of the fourth lens and the fifth lens is greater than or equal to 24.18 mm and less than or equal to 24.58 mm, and the air gap between the edge positions of the fifth lens and the sixth lens is greater than or equal to 4.63 mm and less than or equal to 5.03 mm.

[0011] Optionally, the central thickness of the first lens ranges from [1.6 mm, 2.0 mm], the central thickness of the second lens ranges from [1.2 mm, 1.6 mm], the central thickness of the third lens ranges from [3.67 mm, 4.07 mm], the central thickness of the fourth lens ranges from [4.8 mm, 5.2 mm], the central thickness of the fifth lens ranges from [3.8 mm, 4.2 mm], the central thickness of the sixth lens ranges from [3.74 mm, 4.14 mm], and the central thickness of the seventh lens ranges from [1.8 mm, 2.2 mm].

[0012] Optionally, the focal length of the lens assembly is greater than or equal to 2.5 mm and less than or equal to 3.0 mm.

[0013] Optionally, the total optical length of the lens assembly is greater than or equal to 64.5 mm and less than or equal to 65.5 mm.

[0014] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all glass lenses.

[0015] Optionally, the lens assembly has an applicable spectral range of 400nm to 700nm.

[0016] Optionally, the lens assembly further comprises a lens barrel, the lens barrel is internally provided with lenses; the lens barrel is provided with at least one heat dissipation part, and the heat dissipation part has a toothed shape in the length direction.

[0017] In some embodiments, the cooking device comprises the lens assembly described above.

[0018] The lens assembly and the cooking device provided by the embodiments of the present disclosure can achieve the following technical effects:

[0019] The lens assembly provided by the embodiments of the present disclosure comprises, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, and the outer diameter of the lenses decreases from the first lens to the seventh lens, and the air gap between adjacent lenses is limited. In this way, the lens assembly can have a large aperture and a large light amount, and the lens effect is clear and sharp, so that the imaging device can observe a clear and beautiful image in an environment with super-high temperature fogging, greatly improving the picture quality of real-time monitoring.

[0020] The general description above and the following description below are exemplary and explanatory only and are not intended to be limiting. BRIEF DESCRIPTION OF DRAWINGS

[0021] One or more embodiments are illustrated by way of example in the figures that are not intended to be limiting of the embodiments. Identical reference numbers in different figures identify identical, functionally similar, and / or structurally similar elements, features, and / or components. Dimensions of elements in the figures can be exaggerated or reduced for clarity and readability.

[0022] Figure 1 is a structural schematic diagram of a cooking device provided by the embodiments of the present disclosure;

[0023] Figure 2 is a structural schematic diagram of a lens assembly provided by the embodiments of the present disclosure;

[0024] Figure 3 is a structural schematic diagram of a lens assembly provided by the embodiments of the present disclosure;

[0025] Figure 4 is a visible light incidence schematic diagram of a lens assembly provided by the embodiments of the present disclosure;

[0026] Figure 5is a schematic diagram of an MTF curve of a lens assembly provided by an embodiment of the present disclosure;

[0027] Figure 6 is a schematic diagram of a relative luminance curve of a lens assembly provided by an embodiment of the present disclosure;

[0028] Figure 7 is a schematic diagram of a distortion curve of a lens assembly provided by an embodiment of the present disclosure;

[0029] Figure 8 is a schematic diagram of a CRA curve of a lens assembly provided by an embodiment of the present disclosure.

[0030] Reference signs:

[0031] 10: inner container; 20: shell; 30: lens; 31: first lens; 32: second lens; 33: third lens; 34: fourth lens; 35: fifth lens; 36: sixth lens; 37: seventh lens; 38: heat insulation glass; 39: photosensitive element; 40: lens barrel; 41: heat dissipation part; 42: heat insulation ring; 43: front lens barrel; 44: rear lens barrel; 45: rubber ring. DETAILED DESCRIPTION

[0032] In order to enable a more detailed understanding of the features and technical content of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure will be described in detail below in conjunction with the drawings, which are only used for reference and do not limit the embodiments of the present disclosure. In the following technical description, in order to facilitate explanation, through multiple details, a sufficient understanding of the disclosed embodiments is provided. However, one or more embodiments can still be implemented without these details. In other cases, in order to simplify the drawings, well-known structures and devices can be simplified.

[0033] The terms "first", "second", and the like in the specification and claims of the embodiments of the present disclosure and the above drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present disclosure described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0034] In the embodiments of the present disclosure, the terms "upper", "lower", "inner", "middle", "outer", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the embodiments of the present disclosure and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to indicating the orientation or positional relationship, the above-mentioned part of the terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0035] In addition, the terms "set", "connected", "fixed" should be broadly understood. For example, "connected" can be fixedly connected, detachably connected, or integrally configured; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0036] Unless otherwise specified, the term "a plurality of" means two or more.

[0037] In the embodiments of the present disclosure, the character " / " represents an "or" relationship between the objects before and after it. For example, A / B means: A or B.

[0038] The term "and / or" is a description of the association between objects, which means that there can be three relationships. For example, A and / or B means: A or B, or, A and B, the three relationships.

[0039] It should be noted that the embodiments in the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0040] At present, in the super-high temperature environment, for example, the working temperature of some cooking devices is usually above 300 DEG C, and there are certain difficulties in image acquisition, mainly in that the light transmittance and light collection amount in the super-high temperature fog environment cannot be effectively guaranteed, and the lens assembly in the related technology cannot consider the characteristics of high temperature resistance and clear imaging.

[0041] The embodiments of the present disclosure provide a cooking device, as shown in Figure 1

[0042] ​Optionally, the cooking device can be an oven, and can also be a super-high-temperature cooking appliance such as an air fryer. Generally, the working temperature of the oven or air fryer is above 200℃, and can even reach above 300℃. In order to meet the user's shooting demand for the food material in the cooking cavity under the super-high-temperature environment, the camera assembly needs to be able to withstand high temperature and clearly image under high temperature. The embodiments of the present disclosure take the oven as an example for illustration.

[0043] Optionally, the oven includes an inner container 10, a shell 20, a door body, and a lens assembly. The inner container 10 constitutes a cooking cavity inside, the shell 20 is arranged outside the inner container 10, the door body is connected with the shell 20, and the lens assembly includes a lens 30. The lens 30 is obliquely arranged on the top surface of the inner container 10 and close to one side of the door body, so as to shoot the surface shape of the food material to be cooked and the height of the food material from the front.

[0044] By obliquely arranging the lens 30 on the top surface of the inner container 10 and close to one side of the door body, the food material in the cooking cavity can be stereoscopically photographed. Not only the upper surface of the food material can be photographed, but also the height of the food material can be photographed. Moreover, the shooting can be performed from the user's front perspective, thereby improving the user's shooting experience.

[0045] The cooking temperature in the oven is usually high. The lens 30 of the lens assembly is arranged on the top surface of the inner container 10 and faces the cooking cavity, which can withstand the high cooking temperature of the oven. Moreover, by arranging seven lenses in the lens 30, the lens assembly can have a large aperture and a large light amount, and can clearly image under the super-high-temperature environment. The shooting effect of the lens 30 is clear and sharp.

[0046] The embodiments of the present disclosure also provide a lens assembly, as shown in Figures 2 to 8 .

[0047] In some embodiments, the lens assembly at least includes a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, a fifth lens 35, a sixth lens 36, and a seventh lens 37 in sequence along the direction of the optical axis from the object side to the image side. The object side of the first lens 31 is a convex surface, and the image side is a concave surface. The object side of the second lens 32 is a convex surface, and the image side is a concave surface. The object side of the third lens 33 is a concave surface, and the image side is a convex surface. The object side of the fourth lens 34 is a concave surface, and the image side is a convex surface. The object side of the fifth lens 35 is a convex surface, and the image side is a concave surface. The object side of the sixth lens 36 is a convex surface, and the image side is a convex surface. The object side of the seventh lens 37 is a concave surface, and the image side is a convex surface. The outer diameter of the lens presents a decreasing trend from the first lens 31 to the seventh lens 37. The air gap between the edge positions of the first lens 31 and the second lens 32 is 0mm. The air gap between the edge positions of the second lens 32 and the third lens 33 is 0mm. The air gap between the edge positions of the sixth lens 36 and the seventh lens 37 is 0mm.

[0048] The lens assembly provided by the embodiments of the present disclosure sequentially comprises, from the object side to the image side along the direction of the optical axis, a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, a fifth lens 35, a sixth lens 36 and a seventh lens 37, and the outer diameter of the lens decreases from the first lens 31 to the seventh lens 37, while the air gap between adjacent lenses is limited. In this way, the lens assembly can have a large aperture and a large light amount, and the lens 30 has a clear and sharp effect, so that the imaging device can observe a clear and beautiful image in an environment with super-high temperature fogging, greatly improving the picture quality of real-time monitoring.

[0049] It can be understood that the first lens 31 is located close to the object to be photographed, and the seventh lens 37 is located away from the object to be photographed and close to the photosensitive element 39. By setting the concave-convex degree of the object side and the image side of the seven lenses, the light can be converged, and the imaging quality of the lens assembly is improved. In addition, the object side of the seventh lens 37 is a concave surface, so that the seventh lens 37 can further disperse the light, and the dispersion of the light by the seventh lens 37 is strengthened, and the dispersed light is irradiated to the photosensitive element 39.

[0050] Alternatively, the curvature radius of the object side of the first lens 31 is in the range of [15.86mm, 16.62mm], the curvature radius of the image side of the first lens 31 is in the range of [7.8mm, 8.2mm]; the curvature radius of the object side of the second lens 32 is in the range of [40.26mm, 40.66mm], the curvature radius of the image side of the second lens 32 is in the range of [8.76mm, 9.16mm]; the curvature radius of the object side of the third lens 33 is in the range of [-22.1mm, -21.7mm], the curvature radius of the image side of the third lens 33 is in the range of [-10.38mm, -9.98mm]; the curvature radius of the object side of the fourth lens 34 is in the range of [-13.75mm, -13.35mm], the curvature radius of the image side of the fourth lens 34 is in the range of [-86.3mm, -85.9mm]; the curvature radius of the object side of the fifth lens 35 is in the range of [8.3mm, 8.7mm], the curvature radius of the image side of the fifth lens 35 is in the range of [115.8mm, 116.2mm]; the curvature radius of the object side of the sixth lens 36 is in the range of [11.25mm, 11.65mm], the curvature radius of the image side of the sixth lens 36 is in the range of [-7.6mm, -7.2mm]; the curvature radius of the object side of the seventh lens 37 is in the range of [-20.4mm, -20.0mm], the curvature radius of the image side of the seventh lens 37 is in the range of [-5.93mm, -5.53mm].

[0051] The radius of curvature of the object side or the image side of each lens in the lens assembly can represent the concave-convex degree of the object side or the image side, and affect the refraction path of the incident light in the lens assembly. By limiting the radius of curvature of the object side and the image side of each lens, the visible light can be refracted from the first lens 31 with a larger outer diameter to the seventh lens 37 with the smallest outer diameter, and then clearly imaged on the photosensitive element 39. The light path diagram of the visible light entering the lens assembly is shown in Figure 4 .

[0052] In the embodiments of the present disclosure, the outer diameters of the lenses in the lens assembly decrease from the first lens 31 to the seventh lens 37. That is, the size of the outer diameter of the lens decreases as a whole from the first lens 31 to the seventh lens 37, and the outer diameters of the lenses are not limited to decrease sequentially. Alternatively, the outer diameters of the lenses can decrease sequentially from the first lens 31 to the seventh lens 37, and can also have the following settings.

[0053] Alternatively, the outer diameter of the second lens 32 is equal to the outer diameter of the third lens 33, and is equal to the outer diameter of the fourth lens 34; the outer diameter of the fifth lens 35 is equal to the outer diameter of the sixth lens 36, and is equal to the outer diameter of the seventh lens 37.

[0054] It can be understood that the outer diameter of the first lens 31 is greater than the outer diameter of the second lens 32, the outer diameters of the second lens 32, the third lens 33 and the fourth lens 34 are equal, the outer diameter of the fourth lens 34 is greater than the outer diameter of the fifth lens 35, and the outer diameters of the fifth lens 35, the sixth lens 36 and the seventh lens 37 are equal.

[0055] Alternatively, the outer diameter of the first lens 31 ranges from [21.5mm, 22.5mm], the outer diameter of the second lens 32 ranges from [17.5mm, 18.5mm], and the outer diameter of the fifth lens 35 ranges from [8.5mm, 9.5mm].

[0056] The outer diameter of the lens is related to the focal power of the lens, which is used to characterize the ability of the optical system to deflect light. By limiting the outer diameter of each lens, the visible light can be refracted from the first lens 31 with a larger outer diameter to the photosensitive element 39 at the rear end of the lens 30, without deviation, thereby improving the imaging quality of the lens assembly.

[0057] Alternatively, the air gap between the edge positions of the third lens 33 and the fourth lens 34 is greater than or equal to 0.7mm and less than or equal to 1.1mm, the air gap between the edge positions of the fourth lens 34 and the fifth lens 35 is greater than or equal to 24.18mm and less than or equal to 24.58mm, and the air gap between the edge positions of the fifth lens 35 and the sixth lens 36 is greater than or equal to 4.63mm and less than or equal to 5.03mm.

[0058] The air gap between the positions of the adjacent lens edges affects the light path of the visible light in the optical system. By limiting the air gap between the adjacent lenses, the visible light can be clearly imaged on the photosensitive element 39, and the length of the lens assembly can be reduced as much as possible, thereby reducing the volume of the lens assembly and facilitating the installation of the lens assembly on the oven.

[0059] Optionally, the central thickness of the first lens 31 is in the range of [1.6mm, 2.0mm], the central thickness of the second lens 32 is in the range of [1.2mm, 1.6mm], the central thickness of the third lens 33 is in the range of [3.67mm, 4.07mm], the central thickness of the fourth lens 34 is in the range of [4.8mm, 5.2mm], the central thickness of the fifth lens 35 is in the range of [3.8mm, 4.2mm], the central thickness of the sixth lens 36 is in the range of [3.74mm, 4.14mm], and the central thickness of the seventh lens 37 is in the range of [1.8mm, 2.2mm].

[0060] The central thickness of the lens is related to the refractive index of the lens. By limiting the range of the central thickness of the lens, the refractive index of the seven lenses can be better matched, and finally the lens assembly can clearly image in the visible light range.

[0061] Optionally, the focal length of the lens assembly is greater than or equal to 2.5mm and less than or equal to 3.0mm.

[0062] The lens assembly provided by the embodiments of the present disclosure is used in an oven. The height of the oven is generally small, usually less than 1m, and even the height of a household oven is within 50cm. For example, the focal length of the lens assembly in the embodiments of the present disclosure can be 2.75mm, and can work in a working distance of more than 6m, which is sufficient to meet the use requirements of the oven and other cooking devices.

[0063] Optionally, the total optical length of the lens assembly is greater than or equal to 64.5mm and less than or equal to 65.5mm.

[0064] The total optical length of the lens assembly is the distance from the object side surface of the first lens 31 to the center axis of the imaging surface. Generally, it is difficult to design a lens 30 that is too long or too short. In the embodiments of the present disclosure, the total optical length of the lens 30 can be 65mm, so that the lens 30 not only has a suitable length, but also can clearly image in the visible light band.

[0065] Optionally, the materials of the first lens 31, the second lens 32, the third lens 33, the fourth lens 34, the fifth lens 35, the sixth lens 36 and the seventh lens 37 are all glass lenses.

[0066] It can be understood that the seven lenses of the embodiment of the disclosure all adopt glass lenses, and there is no need to use glued lenses and the like, and the structure is simple. By setting the parameters of the glass lenses, clear imaging in the visible light wave band under an ultrahigh-temperature environment can be realized, and the imaging quality is high.

[0067] Optionally, the first lens 31, the second lens 32, the third lens 33, the fourth lens 34, the fifth lens 35, the sixth lens 36 and the seventh lens 37 are all high-temperature-resistant glass lenses.

[0068] It can be understood that the lens assembly of the embodiment of the disclosure is used in an oven and the like ultrahigh-temperature cooking environment, and the lenses need to have heat resistance. By setting the seven lenses to be high-temperature-resistant glass, damage of the lens assembly in an ultrahigh-temperature use environment can be prevented.

[0069] Optionally, the lens assembly further comprises heat insulation glass 38, which is arranged at the front end of the first lens 31, as shown in Figure 3 .

[0070] In the embodiment of the disclosure, the seven lenses are arranged behind the heat insulation glass 38 at the front end of the lens 30, and the heat insulation glass 38 can block part of the heat in the cooking cavity from entering the inside of the lens 30. The plurality of lenses are also high-temperature-resistant glass. In this way, the lens assembly can withstand the high temperature inside the oven.

[0071] Optionally, the applicable spectral range of the lens assembly is 400 nm to 700 nm.

[0072] The lens assembly provided by the embodiment of the disclosure is suitable for a cooking device, such as an oven or an air fryer and the like. The wave band of light in the oven is mostly the visible light wave band, and may also contain a small amount of near-infrared light emitted by a heat pipe. In this way, the working wave band of the lens assembly capable of imaging is the visible light wave band 400 nm to 650 nm and the near-infrared light wave band 650 nm to 700 nm. After imaging on the photosensitive element 39, the lens assembly can be received by the human eye, the imaging is real and natural, and the resolution is high.

[0073] The optical parameters of each lens in a lens assembly provided by an embodiment of the disclosure are listed in Table 1 below.

[0074]

[0075]

[0076] Wherein, L1 is the first lens 31, L2 is the second lens 32, L3 is the third lens 33, L4 is the fourth lens 34, L5 is the fifth lens 35, L6 is the sixth lens 36, L7 is the seventh lens 37. R1 represents the side of the lens facing the object side, that is, the object side of the lens. R2 represents the side of the lens facing the image side, that is, the image side of the lens. R represents the radius of curvature of the object side or the image side of the lens. nd represents the refractive index of each lens.

[0077] Figure 5 Figure 4 is a MTF performance diagram of the lens assembly shown in Table 1. The MTF curve shows the contrast restoration of the lens 30, the vertical axis represents the pros and cons of the contrast, and the horizontal axis represents the distance from the imaging center. The multiple curves of different forms in the figure are the resolution of the lens 30 at different field positions. The more concentrated and closer to 1, the higher the resolution of the lens assembly at different field positions, that is, the center and edge positions of the field of view can be clearly imaged, the edge position of the field of view will not be blurred, and the imaging quality is high. The image acquisition resolution of the lens assembly shown in Table 1 can reach 1080P, which can provide high-definition resolution.

[0078] Figure 6 Figure 5 is a relative illumination curve of the lens assembly shown in Table 1. Relative illumination represents the brightness ratio of the image edge and center. The higher the relative illumination, the better the uniformity of the final imaging, and the clearer the image. The relative illumination of the lens assembly shown in Table 1 is greater than 61%.

[0079] Figure 7 Figure 6 is a distortion curve of the lens assembly shown in Table 1. The closer the curve in the figure to the middle reference line, the better the distortion performance of the lens 30. The smaller the distortion percentage, the higher the imaging quality of the lens 30, and the smaller the image deformation. The optical distortion of the lens assembly shown in Table 1 is less than 10%, which can reach 8.9%, and the image deformation is very small, and the imaging quality is high.

[0080] Figure 8 Figure 7 is a CRA curve diagram of the lens assembly shown in Table 1. Figure 8 The curve in Figure 7 is the chief ray of the photosensitive element 39, and the straight line is the chief ray of the lens assembly, and the chief ray of the lens assembly changes linearly, Figure 8 The closer the curve and the straight line in Figure 7, the better the chief ray angle performance of the lens assembly, and the clearer the imaging. The chief ray angle of the lens assembly provided by the embodiment of the present disclosure can reach 5 degrees at most.

[0081] The lens assembly in the embodiment of the present disclosure has a high image acquisition resolution by setting 7 lenses and limiting the related parameters of the lenses, and the optical deformation is less than 10%, which can clearly image in the wavelength band of 400nm to 700nm, and the imaging quality is high.

[0082] Optionally, the lens assembly further comprises a lens barrel 40, the lens barrel 40 is internally provided with a lens; the lens barrel 40 is provided with at least one heat dissipation part 41, the heat dissipation part 41 is in the shape of a gear in the length direction.

[0083] It can be understood that the optical axis of the lens assembly can coincide with the central axis of the lens barrel 40. As shown in the figure, the middle part of the lens barrel 40 is the heat dissipation part 41, and the heat dissipation part 41 is arranged around the outside of the lens. Figure 2 The heat dissipation part 41 comprises a plurality of heat dissipation teeth arranged in the axial direction of the lens 30, and the plurality of heat dissipation teeth are arranged around the middle part of the lens barrel 40. The heat dissipation part 41 is designed in the shape of a gear, which can increase the heat dissipation area of the lens barrel 40 and improve the heat dissipation efficiency of the lens barrel 40, which is conducive to the dissipation of heat in the lens 30, so that the heat conducted from the front end of the lens 30 to the middle part of the lens barrel 40 is reduced, greatly reducing the temperature of the photosensitive element 39 at the end of the lens barrel 40. For example, the temperature of the front end of the lens 30 is 320℃, and after heat dissipation by the heat dissipation part 41, the temperature of the lens 30 can be about 150℃, and the heat dissipation teeth can effectively cool the lens 30.

[0084] Optionally, the shape of the tooth top of the heat dissipation tooth can be sawtooth-shaped or planar. The sawtooth-shaped or planar tooth top can both increase the heat dissipation area of the heat dissipation part 41 and improve the heat dissipation efficiency of the lens barrel 40. The shape of the tooth top of the heat dissipation tooth is not specifically limited in the present application.

[0085] Optionally, the material of the heat dissipation part 41 is aluminum alloy.

[0086] It can be understood that the material of the heat dissipation part 41 is aluminum alloy, which is conducive to the heat dissipation of the lens 30 and can also withstand the high temperature in the oven, so that the temperature of the lens 30 is reduced and the heat transferred to the rear end of the lens 30 is greatly reduced, which is conducive to improving the high temperature resistance of the lens 30.

[0087] Optionally, the lens barrel 40 further comprises a front lens barrel 43 and a rear lens barrel 44, and the heat dissipation part 41 is arranged between the front lens barrel 43 and the rear lens barrel 44.

[0088] Optionally, the material of the front lens barrel 43 is stainless steel.

[0089] It can be understood that the stainless steel material not only has high temperature resistance, but also has fast heat dissipation, and can withstand the high temperature in the cooking cavity of the oven when arranged at the front end of the lens barrel 40. Moreover, the front end of the lens 30 can also be quickly cooled, avoiding that the high heat is stored in the lens 30 for a long time and causing damage to the lens in the lens 30. At the same time, the heat transferred to the rear end of the lens 30 can also be reduced.

[0090] Optionally, the lens barrel 40 further comprises a heat insulation ring 42, which is connected with the heat dissipation part 41 and arranged at the rear of the heat dissipation part 41. The heat insulation ring 42 can block the heat in the cooking cavity from entering the lens 30. The heat at the front end of the lens 30 gradually decreases through the heat dissipation part 41, and the temperature of the lens 30 will not continue to rise after passing through the heat insulation ring 42.

[0091] Optionally, the material of the heat insulation ring 42 is PEEK (polyether ether ketone) material.

[0092] It can be understood that PEEK material is a special engineering plastic with excellent properties such as high temperature resistance, self-lubrication, easy processing and high mechanical strength, and good plasticity. Using PEEK material for the lens barrel 40 can effectively insulate the lens 30.

[0093] Optionally, the rear lens barrel 44 is provided with the heat dissipation part 41.

[0094] In order to distinguish the position of the heat dissipation part 41, we define the heat dissipation part 41 in the front of the heat insulation ring 42 as the first heat dissipation part 41, and the heat dissipation part 41 in the rear of the heat insulation ring 42 as the second heat dissipation part. The structures of the first heat dissipation part and the second heat dissipation part can be the same and can both include a plurality of heat dissipation teeth.

[0095] By arranging heat dissipation teeth in the front and rear of the heat insulation ring 42, the lens 30 can be effectively cooled, the temperature of the lens 30 is reduced, the heat transferred to the photosensitive element 39 at the rear end of the lens barrel 40 is reduced, and the temperature resistance of the lens 30 is improved. For example, the temperature at the front end of the lens 30 is about 320℃, the temperature of the lens 30 is about 150℃ after passing through the first heat dissipation part, the temperature of the lens 30 is about 70℃ after passing through the heat insulation ring 42 and the second heat dissipation part, and the working temperature of the photosensitive element 39 at the rear end of the lens 30 is about 55℃. In this way, through the temperature resistance and heat insulation of the lens 30, the working temperature of the internal working elements of the lens 30 is reduced, so that the lens 30 can balance the temperature resistance and the clear imaging characteristics.

[0096] Optionally, a rubber ring 45 is arranged between the front lens barrel 43 and the heat dissipation part 41 to prevent the lens 30 from being damp during use. Optionally, rubber rings 45 are arranged between the rear lens barrel 44 and the heat insulation ring 42 and between the heat dissipation part 41 and the heat insulation ring 42, which can also prevent the lens 30 from being damp during use.

[0097] The above description and drawings suffice to fully enable one skilled in the art to practice the embodiments of the present disclosure. Other embodiments can include structural and other changes. The embodiments are merely representative of possible variations. Individual components and functions are optional unless explicitly required, and the order of operations can be varied. Portions and features of some embodiments can be included in, or substituted for, portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the drawings, and can be varied in a variety of ways. The scope of the present disclosure is limited only by the claims that follow.

Claims

1. A lens assembly, characterized by, The lens assembly is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens from the object side to the image side along the direction of the optical axis: the first lens has a convex object side surface and a concave image side surface; the second lens has a convex object side surface and a concave image side surface; the third lens has a concave object side surface and a convex image side surface; the fourth lens has a concave object side surface and a convex image side surface; the fifth lens has a convex object side surface and a concave image side surface; the sixth lens has a convex object side surface and a convex image side surface; the seventh lens has a concave object side surface and a convex image side surface; wherein the outer diameter of the lenses decreases from the first lens to the seventh lens, the air gap between the edge positions of the first lens and the second lens is 0 mm, the air gap between the edge positions of the second lens and the third lens is 0 mm, the air gap between the edge positions of the sixth lens and the seventh lens is 0 mm, the air gap between the edge positions of the fourth lens and the fifth lens is greater than or equal to 24.18 mm and less than or equal to 24.58 mm, and the total optical length of the lens assembly is greater than or equal to 64.5 mm and less than or equal to 65.5 mm.

2. The lens assembly according to claim 1, wherein: the outer diameter of the second lens is equal to the outer diameter of the third lens and equal to the outer diameter of the fourth lens; the outer diameter of the fifth lens is equal to the outer diameter of the sixth lens and equal to the outer diameter of the seventh lens.

3. The lens assembly according to claim 1, wherein: the air gap between the edge positions of the third lens and the fourth lens is greater than or equal to 0.7 mm and less than or equal to 1.1 mm, and the air gap between the edge positions of the fifth lens and the sixth lens is greater than or equal to 4.63 mm and less than or equal to 5.03 mm.

4. The lens assembly according to claim 1, wherein: the central thickness of the first lens ranges from [1.6 mm, 2.0 mm], the central thickness of the second lens ranges from [1.2 mm, 1.6 mm], the central thickness of the third lens ranges from [3.67 mm, 4.07 mm], the central thickness of the fourth lens ranges from [4.8 mm, 5.2 mm], the central thickness of the fifth lens ranges from [3.8 mm, 4.2 mm], the central thickness of the sixth lens ranges from [3.74 mm, 4.14 mm], and the central thickness of the seventh lens ranges from [1.8 mm, 2.2 mm].

5. The lens assembly according to claim 3, wherein: the focal length of the lens assembly is greater than or equal to 2.5 mm and less than or equal to 3.0 mm.

6. The lens assembly according to claim 1, wherein: the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all glass lenses.

7. The lens assembly according to claim 1, wherein: The lens assembly has an applicable spectral range of 400 nm to 700 nm.

8. The lens assembly according to any one of claims 1 to 7, wherein, Further comprising: a lens barrel having a lens disposed therein; at least one heat dissipation portion is disposed on the lens barrel, and the cross-sectional shape of the heat dissipation portion in the length direction thereof is tooth-shaped.

9. A cooking apparatus characterized by, including the lens assembly according to any one of claims 1 to 8.

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