lens barrel

Abstract

The invention relates to a lens barrel, comprising a lens barrel body (1) coaxial with the lens barrel centerline and a lens barrel head (2) located at the object side end of the lens barrel body (1); the inner wall of the lens barrel head (2) is provided with a first conical surface (201) coaxial with the lens barrel centerline and with the cone bottom located on the object side; the first conical surface (201) is provided with an annular groove (2011) arranged in sequence along the axis of the first conical surface (201); the annular groove (2011) is composed of a first cylindrical surface (2011a) and a second conical surface (2011b) coaxial with the lens barrel centerline; the angle between the first cylindrical surface (2011a) and the second conical surface (2011b) constituting each annular groove (2011) faces the object side of the lens barrel. The lens barrel of the invention can improve the stray light generated by the lens barrel head to the greatest extent while ensuring sufficient light transmission, so as to achieve better imaging effect of the lens.

Description

Technical Field

[0001] The present invention relates to the field of imaging equipment, and in particular to a lens barrel. Background Art

[0002] Against the backdrop of the rise of "hole-punch" screen phones, the current development trend of mobile phone lenses is small heads and large image surfaces, especially front-facing cameras. In order to ensure that the size of the lens barrel head is small while having sufficient light transmittance, the lens disclosed in patent CN208636528U sets the front end of the lens into a horn mouth. The first conical surface at the horn mouth will cause stray light, seriously affecting the image quality. In addition to setting a light baffle, the patent's method of extincting stray light is to set a conical surface on one of the lenses and coat the conical surface with a matte material. However, this method will affect the imaging effect of the lens itself, and the matte effect is not ideal. Summary of the Invention

[0003] The object of the present invention is to provide a lens barrel with better imaging effect.

[0004] To achieve the above object, the present invention provides a lens barrel, comprising a lens barrel body coaxial with the lens barrel center line and a lens barrel head located at the object side end of the lens barrel body;

[0005] The inner wall of the lens barrel head has a first conical surface coaxial with the center line of the lens barrel and with the cone bottom located on the object side;

[0006] The first conical surface is provided with annular grooves arranged in sequence along the axis of the first conical surface;

[0007] The annular groove is composed of a first cylindrical surface and a second conical surface coaxial with the center line of the lens barrel;

[0008] The included angle between the first cylindrical surface and the second conical surface constituting each annular groove faces the object side of the lens barrel.

[0009] According to one aspect of the present invention, the cone bottom of the second conical surface is located on the image side.

[0010] According to one aspect of the present invention, the number of the annular grooves is 15 to 50;

[0011] An included angle θ between the first cylindrical surface and the second conical surface of the annular groove satisfies the following: 45°≤θ≤60°, in particular, θ=45°.

[0012] According to one aspect of the present invention, the dimension h of the first cylindrical surface along the axial direction of the lens barrel is ≤ 0.03 mm, in particular h = 0.03 mm;

[0013] The difference between the radii of the object-side end and the image-side end of the second conical surface is k≤0.02 mm, in particular k=0.01 mm.

[0014] According to one aspect of the present invention, the included angle β between the first conical surface and the center line of the lens barrel satisfies: 20°≤β≤35°, in particular, β=30°.

[0015] According to one aspect of the present invention, the outer diameter a of the object side end of the lens barrel head satisfies: 1mm≤a≤2.2mm;

[0016] A distance c between the object-side end surface and the image-side end surface of the lens barrel head along the axial direction of the lens barrel satisfies: c≥0.4 mm.

[0017] According to one aspect of the present invention, the lens barrel head and the lens barrel body are connected via a connecting structure;

[0018] The wall thickness e of the connection structure satisfies: e≥0.1mm.

[0019] According to one aspect of the present invention, the connecting structure is an annular structure perpendicular to the center line of the lens barrel;

[0020] The distance d1 between the object side end surface of the lens barrel head and the object side wall of the connecting structure along the lens barrel axial direction is ≥ 0.2 mm, in particular d1 = 0.45;

[0021] The wall thickness of the connecting structure is e = 0.15 mm;

[0022] The dimension of the first conical surface along the axial direction of the lens barrel is f1 = 0.36 mm;

[0023] The distance between the object side end face and the image side end face of the lens barrel head along the lens barrel axial direction is c = 0.65 mm;

[0024] The outer diameter of the object side end of the lens barrel head is a=2mm.

[0025] According to one aspect of the present invention, the outer wall of the connecting structure and the outer wall of the lens barrel head are continuous conical surfaces;

[0026] The distance d2 between the object side end surface of the lens barrel head and the object side end of the lens barrel body along the lens barrel axial direction is ≥ 0.2 mm, especially d2 = 0.67 mm;

[0027] The wall thickness of the connecting structure is e = 0.18 mm;

[0028] The dimension of the first conical surface along the axial direction of the lens barrel is f2 = 0.51 mm;

[0029] The distance between the object side end face and the image side end face of the lens barrel head along the lens barrel axis is c = 0.45 mm;

[0030] The outer diameter of the object side end of the lens barrel head is a=1.9mm.

[0031] According to one aspect of the present invention, the object side end surface and the inner wall of the lens barrel head are both subjected to laser atomization processing.

[0032] According to one embodiment of the present invention, an annular groove is provided along the axis of the first conical surface. The annular groove is formed by a first cylindrical surface and a second conical surface, with the base of the second conical surface located on the image side. This arrangement of the annular groove allows light to be reflected from both surfaces of the first conical surface within the groove when it strikes the first conical surface, thereby reducing the amount of stray light that directly reaches the imaging sensor after a single reflection from the first conical surface. This prevents the smooth conical surface from generating significant amounts of reflected light that enters the lens barrel and creates stray light.

[0033] According to one embodiment of the present invention, a first conical surface disposed on the inner wall of the lens barrel head with its base on the object side can prevent the smaller lens barrel head from blocking effective imaging light. The angle between the first conical surface and the lens barrel centerline is 20°≤β≤35°. Within this angle range, the first conical surface neither obstructs effective imaging light nor effectively redirects incident light after reflection, thereby reducing the amount of stray light reflected into the lens barrel.

[0034] According to one solution of the present invention, the number of annular grooves is 15 to 50. This arrangement is beneficial to improving the stray light of the lens barrel head and is also beneficial to the molding and mold design of the annular grooves.

[0035] According to one solution of the present invention, the angle θ between the first cylindrical surface and the second conical surface satisfies: 45°≤θ≤60°. Within this angle range, stray light can be effectively reduced while ensuring the strength and molding process of the groove.

[0036] According to one embodiment of the present invention, the distance c between the object-side end face and the image-side end face of the lens barrel head along the lens barrel axis satisfies the requirement of c ≥ 0.4 mm. This distance allows the aperture stop in the lens assembly of the present invention to be relatively far from the first lens element, allowing the lens barrel head to be made very small, meeting the requirements of "hole-punch" screen mobile phones.

[0037] According to one embodiment of the present invention, the wall thickness e of the connecting structure satisfies: e≥0.1 mm, thereby ensuring the strength of the lens barrel and the stability and reliability of the assembled lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a cross-sectional view schematically showing a lens assembly in a lens barrel according to a first embodiment of the present invention;

[0039] Figure 2 yes Figure 1 A partial enlarged view of the lens barrel head and connecting structure;

[0040] Figure 3 yes Figure 1A local enlarged view of the first conical surface in FIG;

[0041] Figure 4 FIG1 is a schematic diagram schematically showing laser atomization of a lens assembled in a lens barrel according to a first embodiment of the present invention;

[0042] Figure 5 is a cross-sectional view schematically showing a lens assembly in a lens barrel according to a second embodiment of the present invention;

[0043] Figure 6 yes Figure 5 A partial enlarged view of the lens barrel head and connecting structure;

[0044] Figure 7 yes Figure 5 A local enlarged view of the first conical surface in FIG;

[0045] Figure 8 FIG2 is a schematic diagram schematically showing laser atomization of a lens assembled in a lens barrel according to a second embodiment of the present invention;

[0046] Figure 9 This is the lens spot diagram and optical path diagram when the lens barrel is f1 = 0.36mm, β = 30° and no annular groove is set;

[0047] Figure 10 The lens spot diagram and optical path diagram are of f1 = 0.36mm, β = 30°, and a θ = 45° annular groove.

[0048] Figure 11 This is the lens spot diagram and light path diagram when the lens barrel with f1 = 0.36mm, β = 30° is set with a θ = 60° annular groove;

[0049] Figure 12 This is the lens spot diagram and light path diagram when the lens barrel is f1 = 0.36mm, β = 25° and no annular groove is set;

[0050] Figure 13 This is the lens spot diagram and light path diagram when the lens barrel with f1 = 0.36mm, β = 25° is set with a θ = 45° annular groove;

[0051] Figure 14 This is the lens spot diagram and optical path diagram when the lens barrel with f1 = 0.36mm, β = 25° is set with a θ = 60° annular groove;

[0052] Figure 15 This is the lens spot diagram and optical path diagram when the lens barrel is f1 = 0.36mm, β = 35° and no annular groove is set;

[0053] Figure 16This is the lens spot diagram and light path diagram when the lens barrel with f1 = 0.36mm, β = 35° is set with a θ = 45° annular groove;

[0054] Figure 17 This is the lens spot diagram and light path diagram when the lens barrel with f1 = 0.36mm, β = 35° is set with a θ = 60° annular groove;

[0055] Figure 18 This is the lens spot diagram and light path diagram when the lens barrel is f2 = 0.51mm, β = 30° and no annular groove is set;

[0056] Figure 19 This is the lens flare diagram when the lens barrel with f2 = 0.51mm, β = 30° is set with a θ = 45° annular groove;

[0057] Figure 20 This is the lens spot diagram when the lens barrel with f2 = 0.51mm, β = 30° is set with a θ = 60° annular groove;

[0058] Figure 21 This is the lens spot diagram and light path diagram when the lens barrel is f2 = 0.51mm, β = 25° and no annular groove is set;

[0059] Figure 22 This is the lens flare diagram when the lens barrel with f2 = 0.51mm, β = 25° is set with a θ = 45° annular groove;

[0060] Figure 23 This is the lens flare diagram when the lens barrel with f2 = 0.51mm, β = 25° is set with a θ = 60° annular groove;

[0061] Figure 24 This is the lens spot diagram and light path diagram when the lens barrel is f2 = 0.51mm, β = 35° and no annular groove is set;

[0062] Figure 25 This is the lens flare diagram when the lens barrel with f2 = 0.51mm, β = 35° is set with a θ = 45° annular groove;

[0063] Figure 26 This is the lens spot diagram when the lens barrel with f2 = 0.51mm, β = 35° is set with θ = 60° annular groove. DETAILED DESCRIPTION

[0064] 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 the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0065] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0066] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0067] Figure 1 is a cross-sectional view schematically showing a lens according to a first embodiment of the present invention; Figure 5 FIG is a cross-sectional view schematically showing a lens according to a second embodiment of the present invention. Figure 1 and Figure 5 The lens assembly of the lens barrel according to the two embodiments of the present invention shown in the figure comprises a lens barrel body 1 and a lens barrel head 2 coaxial with the center line of the lens barrel. Figure 1 and Figure 5 The left side of the image is Figure 1 and Figure 5 On the right side, the lens barrel head 2 is located at the object side end of the barrel body. Figure 1 and Figure 5 The lens barrel in the lens shown is cylindrical in shape as a whole, and its outer wall is stepped, with the outer diameter gradually decreasing from the image side end to the object side end. The inner wall of the lens barrel is also a stepped surface to facilitate the installation of the lens group 5. In order to make the lens meet the requirements of the small head of the "hole-punch" screen mobile phone, the outer diameter of the lens barrel head 2 is relatively small. In order to ensure that the lens has sufficient light transmission, the inner wall of the object side end of the lens barrel head 2 is provided with a first conical surface 201 with the cone bottom located on the object side of the lens barrel to avoid blocking the effective imaging light. Figure 1 and Figure 5As can be seen, the diaphragm 4 in the lens of the lens barrel of the present invention is mounted on the object-side end surface of the lens barrel head 2, i.e., the diaphragm is positioned in front. This increases the axial dimension of the lens barrel head 2, and consequently, the size of the first conical surface 201. However, a smooth conical surface with a large size can cause light to reflect after impinging on it, resulting in severe stray light. Conventional processes such as discharge on the reflective surface, laser atomization, and sandblasting are not ideal for improving stray light. Therefore, the present invention primarily improves the structure of the first conical surface 201 to address the drawback of existing lenses that they cannot effectively eliminate or reduce stray light.

[0068] Figures 1 to 4 The schematic diagrams shown are all used to explain the lens barrel according to the first embodiment of the present invention; Figure 2 yes Figure 1 A partial enlarged view of the lens barrel head 2 and the connecting structure 3. Figure 1 and Figure 2 The lens barrel head 2 is a hollow cylinder extending from the object side to the image side along the center line of the lens barrel until it reaches the first lens group 501 from left to right in the figure, and its outer surface is cylindrical. The lens barrel head 2 is connected to the lens barrel body 1 through a connecting structure 3. According to the first embodiment of the present invention, the connecting structure 3 is basically a circular ring coaxial with the center line of the lens barrel, and its outer surface (i.e. Figure 2 The upper middle end) is connected to the lens barrel 1, and the inner surface of the ring (i.e. Figure 2 In this application, although the above distinction between the lens barrel head 2 and the connecting structure 3 is adopted, this is only for the purpose of describing the technical solution of this application and is not a necessary separate component or part in the actual structure. Figure 1 and 2 As shown, the object side end face of the lens barrel head 2 is used to install the aperture 4, while the image side end face and the connecting structure 3 are used together to support the first lens 501 located on the object side of the lens group 5. In the present invention, the distance c between the object side end face and the image side end face of the lens barrel head 2 along the axial direction of the lens barrel should meet the following requirements: c ≥ 0.4 mm (the distance c can also be understood as the axial distance between the aperture 4 and the supporting surface of the first lens). And the outer diameter a of the object side end of the lens barrel head 2 should meet the following requirements: 1 mm ≤ a ≤ 2.2 mm. The lens barrel configured in this way not only meets the requirements of a smaller head size, but also ensures that the axial length of the lens barrel is shorter, thereby making the axial dimension of the first conical surface 201 shorter, thereby reducing the reflection of light at the first conical surface 201. Figure 1 In the first embodiment shown, c=0.65 mm and a=2 mm.

[0069] from Figure 2It can be clearly seen that the first conical surface 201 is located on the inner wall of the lens barrel head 2 near the object side end. The first conical surface 201 constitutes a hollow truncated cone, the axis of the hollow cone is coaxial with the axis of the lens barrel, and the bottom of the cone is located on the object side. The dimension f1 of the first conical surface 201 along the axial direction of the lens barrel is = 0.36mm. In this embodiment, the dimension f1 = 0.36mm of the first conical surface 201 along the axial direction of the lens barrel is mainly suitable for reducing the stray light generated by the 49° incident light irradiating the first conical surface 201. Thus, the connecting structure 3 is annular, having two left and right side walls, and its image side wall (i.e. Figure 2 The left and right side walls of the connecting structure 3 of the present invention are not absolutely flat; their shape is adapted to the supporting surface of the first lens 501. The thickness e of the connecting structure 3 of the present invention should satisfy the following requirement: e ≥ 0.1 mm. This ensures the strength of the lens barrel and the stability and reliability of the assembled lens. The distance d1 between the object-side end face of the lens barrel head 2 and the object-side sidewall of the connecting structure 3 along the axial direction of the lens barrel is ≥ 0.2 mm. In this embodiment, the thickness e of the connecting structure 3 is 0.15 mm, and d1 is 0.45 mm.

[0070] Figure 3 yes Figure 2 The partial enlarged view at the first conical surface 201 shows in detail the structure of the first conical surface 201 of the present invention. Figure 3As can be seen, in order to prevent light from directly reflecting at the first conical surface 201, thereby generating a large amount of stray light, the present invention provides annular grooves 2011 arranged in sequence along the axis of the first conical surface 201. The annular grooves 2011 are composed of a first cylinder 2011a and a second conical surface 2011b coaxial with the lens barrel centerline. The angle between the first cylindrical surface 2011a and the second conical surface 2011b that constitute each annular groove 2011 is open toward the lens barrel object side. The second conical surface 2011b forms a truncated cone with its base on the image side. The method of arranging the grooves on the conical surface in this way can cause light to reflect between the first cylindrical surface 2011a and the second conical surface 2011b inside the grooves, thereby preventing light from directly reflecting on the first conical surface 201 and entering the lens barrel to generate a large amount of stray light. According to the present invention, 15 to 50 annular grooves 2011 are provided. This not only helps eliminate or reduce stray light at the object-side end of the lens barrel head 2, but also facilitates the molding and mold design of the annular groove 2011. To achieve the purpose of the present invention, the angle θ between the first cylindrical surface 2011a and the second conical surface 2011b of each annular groove 2011 should satisfy the following: 45°≤θ≤60°. The dimension h of the first cylindrical surface 2011a along the lens barrel axial direction is ≤0.03mm, and the difference in radius between the object-side end and the image-side end of the second conical surface 2011b is ≤0.02mm. This arrangement can effectively reduce or eliminate stray light while also effectively ensuring the strength and molding process of the annular groove 2011. In particular, the cone angle of the first conical surface 201 directly affects the amount of stray light generated. According to the present invention, the larger the semi-conical angle of the first conical surface 2011, the more it can prevent light from being reflected into the lens barrel and causing stray light. However, if the semi-conical angle is too large, it will affect the amount of light passing through, hindering effective imaging light. Therefore, to achieve the purpose of the present invention, the semi-cone angle β of the first conical surface 201 satisfies: 20°≤β≤35°. Within this angle range, sufficient light throughput can be ensured while changing the direction of the reflected light to reduce the amount of light reflected into the lens barrel. Figures 1 to 4 In the illustrated embodiment, the semi-cone angle β of the first conical surface 201 is 30°. This angle neither obstructs effective light nor prevents light reflected from the conical surface from entering the lens barrel. In one embodiment, 20 annular grooves 2011 are provided. The angle θ between the first cylindrical surface 2011a and the second conical surface 2011b is 45°. The dimension h of the first cylindrical surface 2011a along the axial direction of the lens barrel is 0.03 mm. The difference in radius between the object-side end and the image-side end of the second conical surface 2011b is k = 0.01 mm. This arrangement makes this embodiment suitable for eliminating stray light generated by incident light at a 49° angle.

[0071] Figure 4 FIG1 shows the laser atomization of the lens at the head of the lens barrel according to the first embodiment of the present invention. Figure 4 As shown, the object side end surface and inner wall of the lens barrel head 2 of the present invention are both laser atomized. Figure 4 A in the figure indicates the area treated by laser atomization. Figure 2 As shown, the atomization process covers the entire first conical surface 201 and the two surfaces of the annular groove 2011 provided thereon, as well as the rest of the inner wall of the lens barrel head 2. The area after laser atomization forms a diffuse reflection surface, which can effectively reduce the surface reflectivity and further improve stray light.

[0072] Figures 5 to 8 The schematic diagrams shown are all used to explain the lens barrel according to the second embodiment of the present invention. Figure 5 As shown, the lens barrel head 2 of the lens barrel according to the second embodiment of the present invention is also connected to the lens barrel body 1 via a connecting structure 3. The outer wall of the connecting structure 3 in this embodiment and the outer wall of the lens barrel head 2 are continuous conical surfaces. The distance d2 between the object side end face of the lens barrel head 2 and the object side end face of the lens barrel body 1 along the axial direction of the lens barrel is ≥0.2mm. In this embodiment, d2 = 0.67mm. The distance c between the object side end face of the lens barrel head 2 and the image side end face along the axial direction of the lens barrel is 0.45mm. The outer diameter a of the object side end of the lens barrel head 2 is 1.90mm. The distance d2 between the object side end face of the lens barrel head 2 and the object side end of the lens barrel body 1 along the axial direction of the lens barrel is 0.67mm (i.e., the overall axial dimension of the lens barrel head 2 and the connecting structure 3).

[0073] Figure 6 yes Figure 5 A partial enlarged view of the lens barrel head 2 and the connecting structure 3. Figure 6 As shown, in this embodiment, although the connection structure 3 supports the first lens 501 in a different manner than in the previous embodiment, its thickness should still comply with the above-mentioned range of limitations on the thickness e of the connection structure 3. Therefore, the thickness e of the connection structure 3 in this embodiment is 0.18 mm. The dimension f2 of the first conical surface 201 along the axial direction of the lens barrel is 0.51 mm. This dimension results in a strong stray light when the incident light at an angle of about 16° strikes the first conical surface 201. Figures 5 to 8 In the illustrated embodiment, the included angle β between the first conical surface 201 and the center line of the lens barrel is 30°.

[0074] Figure 7 yes Figure 6 A partial enlarged view of the first conical surface 201 to illustrate the structure of the annular groove 2011. Figures 5 to 8 The structure and size of the annular groove 2011 in the embodiment shown are the same as those in the first embodiment, except that this embodiment has 28 annular grooves 2011. This arrangement makes this embodiment suitable for eliminating stray light generated by 16° incident light.

[0075] Figure 8 FIG2 shows a laser atomization control diagram of a lens at the head of a lens barrel according to a second embodiment of the present invention. Figure 8 As shown, the laser atomization method of this embodiment is the same as that of the first embodiment (the area treated by laser atomization is also represented by A).

[0076] Figures 9 to 17 The figure shows the spot diagram and optical path diagram when the dimension f1 of the first conical surface 201 in the lens barrel along the axial direction is 0.36 mm. Figure 9 、 Figure 12 and Figure 15 No annular groove is provided on the first conical surface 201 of the lens barrel, while the angle θ of the annular groove 2011 in other figures is changed relative to the first embodiment for comparison. Figures 9 to 17 The optical system (i.e. lens group 5) generates strong stray light after the incident light of 49° is refracted and reflected on the first conical surface 201 with f1=0.36mm. Figures 9 to 17 Only the 49° incident light is shown. Figures 9 to 17 The darker the spot in the left-center spot diagram, the stronger the stray light. The light path diagram on the right has the same number of input light rays and the same intensity of each ray. Therefore, the denser the light rays refracted by the optical system, the stronger the stray light.

[0077] Figure 10 and Figure 11 The shown barrel has β = 30°. Figure 10 An annular groove 2011 with an angle of θ = 45° is provided; Figure 11 An annular groove 2011 with θ=60° is provided. Figure 13 and Figure 14 The shown barrel has β = 25°. Figure 13 An annular groove 2011 with an angle of θ = 45° is provided; Figure 14 An annular groove 2011 with θ=60° is provided. Figure 16 and Figure 17 The shown barrel has β=35°. Figure 16 An annular groove 2011 with an angle of θ = 45° is provided; Figure 17 An annular groove 2011 with an angle of θ=60° is provided. It can be seen that the light spot diagram in the above figure is different from that in the Figure 9 、 Figure 12 and Figure 15 There are fewer dark spots in the image, and the light path diagram on the right is also sparse. It can be seen that the lens barrel with the annular groove 2011 of the present invention can significantly reduce stray light. Figure 10 、 Figure 13 and Figure 16It can be seen that, when the specifications of the annular groove 2011 are the same, the larger the angle between the first conical surface 201 and the center line of the lens barrel is, the more obvious the effect of eliminating stray light is.

[0078] Figure 9 The lens barrel shown is not provided with the annular groove 2011, and Figure 10 In the middle is a lens barrel with an annular groove 2011. In addition, Figure 9 and 10 The rest of the lens barrel is the same as in the . Figure 9 and Figure 10 As can be seen from the optical path diagram, Figure 9 In the optical path diagram, the refracted light below the optical axis is relatively dense, while Figure 10 The light distribution in the middle right optical path diagram is relatively uniform, which indicates that the provision of the annular groove 2011 effectively reduces or eliminates stray light entering the imaging sensor.

[0079] Figures 18 to 26 It shows the light spot diagram and / or light path diagram when the dimension f2 of the first conical surface 201 in the lens barrel along the axial direction of the lens barrel is 0.51 mm. Figure 18 、 Figure 21 and Figure 24 The lens barrel in FIG. 1 is not provided with an annular groove, while the angle θ of the annular groove 2011 in other figures is changed relative to the second embodiment to form a contrast. Figures 18 to 26 The optical system generates strong stray light after the incident light of 16° is refracted and reflected on the first conical surface 201 with f2 = 0.51 mm. Figures 18 to 26 Only the incident light at 16° is shown. Figures 18 to 26 The darker the spot in the center spot diagram, the stronger the stray light. The input light in the optical path diagram is the same, and the intensity of each light is also the same. Therefore, the denser the light after refraction by the optical system, the stronger the stray light.

[0080] Figure 19 and Figure 20 The shown barrel has β = 30°. Figure 19 An annular groove 2011 with an angle of θ=45° is provided; Figure 20 An annular groove 2011 with a θ=60° is provided. Figure 22 and Figure 23 The shown barrel has β = 25°. Figure 22 An annular groove 2011 with an angle of θ=45° is provided; Figure 23 An annular groove 2011 with a θ=60° is provided. Figure 25 and Figure 26 The shown barrel has β=35°. Figure 25 An annular groove 2011 with an angle of θ=45° is provided; Figure 26A circular groove 2011 with a θ=60° angle is provided. Figure 18 、 Figure 21 and Figure 24 It can be seen that the lens assembly without the annular groove 2011 produces a large number of dark spots (i.e., strong stray light), while no obvious spots are seen in other views, so the right light view is not shown. It can be seen that the lens barrel with the annular groove 2011 according to the second embodiment of the present invention can greatly reduce or even eliminate (elimination means that the stray light can be ignored in actual shooting) the stray light generated by the 16° incident light. Figure 19 、 Figure 22 and Figure 25 It can also be seen that, when the specifications of the annular groove 2011 are the same, the larger the angle between the first conical surface 201 and the center line of the lens barrel, the more obvious the effect of eliminating stray light.

[0081] The above description is merely one embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A lens barrel, comprising a lens barrel body (1) coaxial with a lens barrel centerline and a lens barrel head (2) located at an object side end of the lens barrel body (1); The inner wall of the lens barrel head (2) has a first conical surface (201) coaxial with the lens barrel centerline and with the cone bottom located on the object side; It is characterized in that The first conical surface (201) is provided with annular grooves (2011) arranged in sequence along the axis of the first conical surface (201); The annular groove (2011) is composed of a first cylindrical surface (2011a) and a second conical surface (2011b) coaxial with the center line of the lens barrel; The included angle between the first cylindrical surface (2011a) and the second conical surface (2011b) constituting each annular groove (2011) faces the object side of the lens barrel; The base of the second conical surface (2011b) is located on the image side; The annular groove (2011) Set 15 to 50; The included angle θ between the first cylindrical surface (2011a) and the second conical surface (2011b) of the annular groove (2011) satisfies: 45°≤θ≤60°; The included angle β between the first conical surface (201) and the center line of the lens barrel satisfies the following: 20°≤β≤35°; The lens barrel head (2) and the lens barrel body (1) are connected via a connecting structure (3); The wall thickness e of the connecting structure (3) satisfies: e≥0.1 mm.

2. The lens barrel according to claim 1, wherein: The dimension h of the first cylindrical surface (2011a) along the axial direction of the lens barrel is ≤ 0.03 mm; The difference k between the radius of the object side end and the image side end of the second conical surface (2011b) is ≤ 0.02 mm.

3. The lens barrel according to claim 1, wherein: The outer diameter a of the object side end of the lens barrel head (2) satisfies: 1mm≤a≤2.2mm; The distance c between the object side end face and the image side end face of the lens barrel head (2) along the axial direction of the lens barrel satisfies: c≥0.4mm.

4. The lens barrel according to claim 1, wherein: The connecting structure (3) is an annular structure perpendicular to the center line of the lens barrel; The distance d1 between the object-side end surface of the lens barrel head (2) and the object-side side wall of the connecting structure (3) along the lens barrel axial direction is ≥0.2 mm; The wall thickness of the connecting structure (3) is e=0.15 mm; The dimension f1 of the first conical surface (201) along the axial direction of the lens barrel is 0.36 mm; The distance between the object side end surface and the image side end surface of the lens barrel head (2) along the lens barrel axial direction is c=0.65 mm; The outer diameter a of the object side end of the lens barrel head (2) is 2 mm.

5. The lens barrel according to claim 1, wherein: The outer wall of the connecting structure (3) and the outer wall of the lens barrel head (2) are continuous conical surfaces; The distance d2 between the object side end surface of the lens barrel head (2) and the object side end of the lens barrel body (1) along the lens barrel axial direction is ≥0.2 mm; The wall thickness of the connecting structure (3) is e=0.18 mm; The dimension f2 of the first conical surface (201) along the axial direction of the lens barrel is 0.51 mm; The distance between the object side end surface and the image side end surface of the lens barrel head (2) along the lens barrel axial direction is c=0.45 mm; The outer diameter a of the object side end of the lens barrel head (2) is 1.9 mm.

6. The lens barrel according to claim 1, wherein: The object side end surface and the inner wall of the lens barrel head (2) are both subjected to laser atomization processing.

Images