Large-F-number day and night lens and imaging method thereof

Abstract

The invention discloses a large-F-number day and night integrated lens and an imaging method thereof, and relates to the technical field of lens imaging, the large-F-number day and night integrated lens comprises six lenses, and the six lenses are sequentially arranged along the axis direction, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. An aperture diaphragm is arranged between the second lens and the third lens, one side of the sixth lens is provided with an optical imaging target surface, the optical imaging target surface is arranged at the tail end of the lens, the first surface and the second surface of the second lens and the second surface of the third lens are aspheric surfaces, the lens adopts a positive + positive + negative + negative + positive + negative focal length combination, and the positive and negative lenses are alternately arranged. The lens in the optical system is regular in shape, large in centering angle, free of inflection points on the aspheric surface and easy to process, and meanwhile the aspheric mirror is made of low-softening glass D-ZK3.

Description

Technical Field

[0001] The present invention relates to the field of lens imaging technology, and more particularly to a large F-number day and night lens and an imaging method thereof. Background Art

[0002] In daily life, the wavelengths of lenses we commonly see are visible light (400nm~780nm, used during the day) or dim light (800nm~900nm, used in the evening and night).

[0003] Of course, there are some day and night lenses on the market with a designed wavelength of 400nm to 900nm, covering visible light and low light, but the lens uses a traditional spherical surface. Due to the large span of the imaging band, this type of lens has disadvantages such as a large number of lenses, a small F number, and a heavy weight.

[0004] In view of the above situation, the present invention designs a large F-number day and night combined lens and an imaging method thereof to solve the above technical problems. Summary of the invention

[0005] In view of the deficiencies in the prior art, an object of the present invention is to provide a large F-number day and night lens and an imaging method thereof.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a large F-number day and night lens, the lens comprising six lenses, the six lenses comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the axial direction, an aperture stop is arranged between the second lens and the third lens, an optical imaging target surface is arranged on one side of the sixth lens, and the optical imaging target surface is arranged at the end of the lens, the first surface and the second surface of the second lens and the second surface of the third lens are aspherical surfaces, the lens adopts a positive + positive + negative + negative + positive + negative focal length combination, and the positive and negative lenses are arranged alternately.

[0007] Preferably, the lens material adopts a crown-crown-crown-crown-flint-flint material combination.

[0008] Preferably, the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens respectively satisfy 140<f1<150, 170<f2<180, -70<f3<-60, -40<f4<-30, 50<f5<60, -40<f6<-30, wherein f1, f2, f3, f4, f5 and f6 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens respectively.

[0009] Preferably, the focal length f1 of the lens and the focal length f of the lens satisfy the following conditions: 3.5<f1 / f<3.75, 4.25<f2 / f<4.5, -1.75<f3 / f<-1.5, -1<f4 / f<-0.75, 1.25<f5 / f<1.5, -1<f6 / f<-0.75, wherein f1, f2, f3, f4, f5, f6 are the focal length values ​​of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, and f is the focal length of the lens.

[0010] Preferably, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are respectively clamped by a lens clamp, and the lens clamp comprises a shell, a control rod, a transmission member and a clamping assembly. A mounting cavity is provided inside the shell, and a through hole is provided in the middle of the shell. A dust ring is provided on one side of the shell, a through hole is provided above the shell, and a control rod is coaxially provided in the through hole. A transmission member is coaxially provided on the control rod, and the rotation of the control rod drives the transmission member to move synchronously. A clamping assembly is connected to one side of the transmission member, and the clamping assembly is provided in the mounting cavity. When the lens is assembled, the control rod rotates to drive the transmission member to rotate, and the rotation of the transmission member drives the clamping assembly to expand or contract, so that the lens can be clamped stably to avoid damage to the corners of the lens.

[0011] Preferably, the transmission member includes a driving gear and a driven gear ring, the driving gear is coaxially arranged with the control rod, and the driving gear is rotatably arranged in the installation cavity, the driven gear ring is arranged on the clamping assembly, and the driving gear and the driven gear ring are meshed with each other, the control rod rotates to drive the driving gear to rotate, and through the meshing of the driving gear and the driven gear ring, the driving gear drives the clamping assembly to expand or contract.

[0012] Preferably, the control rod includes a locking piece and a threaded end, and the control rod is rotatably arranged with the through hole, one end of the control rod is provided with a threaded end, and the other end of the control rod is provided with a threaded groove matching the threaded end, the locking piece is provided on the outer circumferential surface of the control rod, and the control rod drives the driving gear to rotate through the locking piece.

[0013] Preferably, the locking member includes a movable sleeve, a connecting spring and a locking block, the control rod is provided with a mounting groove, the driving gear is provided with an annular groove, and a magnet is arranged in the annular groove, the mounting groove is provided with an ejection outlet of the locking block near the annular groove, the mounting groove is slidably provided with a movable sleeve, the movable sleeve is provided with a plurality of connecting springs in an annular array near one end of the annular groove, one end of the connecting spring is fixedly connected to the movable sleeve, and the other end of the connecting spring is connected to the locking block, the movable sleeve moves so that the locking block fits with the magnet, and at this time, the rotation of the control rod drives the driving gear to move synchronously.

[0014] Preferably, the clamping assembly includes a fixed plate, a driving plate and a clamping block, one side of the fixed plate is fixedly connected to the mounting cavity, and a limiting groove is provided in an annular array on the fixed plate, a driving plate is provided on the side of the fixed plate away from the inner wall of the mounting cavity, a driving groove is provided in an annular array on the driving plate, and a plurality of clamping blocks are provided between the driving plate and the fixed plate, a driving rod is provided at one end of the clamping block, a limiting rod is provided at the other end of the clamping block, and a fixing groove for fixing the lens is provided in the middle of the clamping block, and an elastic element is installed in the fixing groove.

[0015] An imaging method for a large F-number day and night lens, the specific steps are as follows:

[0016] Step 1: The operator first takes out the lens, and then places the lens in a fixing groove on the clamping block. The elastic element provided in the fixing groove can prevent the corners of the lens from being damaged;

[0017] Step 2: During the lens clamping process, the operator first pushes the moving sleeve, which drives the locking block to move into the annular groove on the driving gear. After the locking block and the annular groove are completely overlapped, the elastic potential energy of the connecting spring makes the locking block fit into the annular groove of the driving gear.

[0018] Step 3: The locking block is adsorbed to the annular groove by the magnet in the annular groove. At this time, the operator rotates the control lever, and the rotation of the control lever drives the driving gear to move coaxially. The driving gear drives the driven gear ring to rotate, and the rotation of the driven gear ring drives the clamping assembly to center, clamp and fix the lens;

[0019] Step 4: After the lens is fixed, if multiple lenses need to be connected in series, the threaded end of one end of the control rod can be fixed to the threaded groove of another lens clamp control rod, so that multiple lenses can be connected in series. At the same time, the dust ring can prevent dust from entering the connection between multiple clamps.

[0020] Beneficial effects of the present invention:

[0021] 1. The optical system is designed with a wavelength band of 400nm to 900nm, which can be used day and night; it can also be downgraded to daytime or nighttime use, with better imaging quality;

[0022] 2. The optical system adopts a heat-free design with a design temperature of -50℃~+60℃. The system has good imaging quality under normal temperature and high and low temperature environments;

[0023] 3. The lenses in the optical system have regular shapes, large centering angles, and aspheric surfaces without inflection points, making them easy to process. At the same time, aspheric lenses use low-softening glass D-ZK3, which is easy to mass-produce by precision molding. The optical system engineering is highly feasible and has strong practical application value. It can be used in monitoring, aiming tools, artificial intelligence and other fields;

[0024] 4. Make full use of the advantages of aspheric surface's strong aberration correction ability, reduce the number of lenses, and make the lens structure simple, small in size and light in weight;

[0025] 5. The present invention can prevent the lens from being damaged at the corners during the assembly process by clamping the lens with a lens clamp. At the same time, multiple lenses can be connected in series. When connected in series, a dustproof ring provided on one side of the shell can prevent gaps between the clamps from causing dust to enter, thereby preventing the lens surface from being dirty. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is an optical diagram of the present invention;

[0027] Figure 2 is a spot diagram of the present invention;

[0028] Figure 3 is a field curvature and distortion diagram of the present invention;

[0029] Figure 4 is a relative illumination diagram of the present invention;

[0030] Figure 5 is an axial chromatic aberration diagram of the present invention;

[0031] Figure 6 is a vertical axis chromatic aberration diagram of the present invention;

[0032] Figure 7 is the diffraction circle energy diagram of the present invention;

[0033] Figure 8 This is the MTF curve diagram of the present invention at room temperature +20 degrees;

[0034] Fig. 9 This is the high temperature +60 degree MTF curve of the present invention;

[0035] Fig.10 This is the high temperature -50 degree MTF curve diagram of the present invention;

[0036] Fig.11 It is a schematic diagram of the overall structure of the lens clamp of the present invention;

[0037] Fig.12 is a half-section view of the overall structure of the lens clamp of the present invention;

[0038] Fig.13 It is a schematic diagram of the overall structure of the transmission member and the clamping assembly of the present invention;

[0039] Fig.14 The present invention Fig.12 A partial enlarged view of the middle A;

[0040] Fig.15 is a half-section view of the overall structure of the control rod of the present invention;

[0041] Fig.16 It is a schematic diagram of the overall structure of the clamping block of the present invention.

[0042] Reference numerals:

[0043] 1. First lens; 2. Second lens; 3. Aperture stop; 4. Third lens; 5. Fourth lens; 6. Fifth lens; 7. Sixth lens; 8. Optical imaging target surface; 10. Housing; 101. Dust ring; 102. Mounting cavity; 103. Through hole; 20. Control rod; 201. Locking member; 2011. Moving sleeve; 2012. Connecting spring; 2013. Locking block; 202. Threaded end; 30. Transmission member; 301. Driving gear; 3011. Annular groove; 3012. Magnet; 302. Driven gear ring; 40. Clamping assembly; 401. Fixed plate; 4011. Limiting groove; 402. Driving plate; 4021. Driving groove; 403. Clamping block; 4031. Driving rod; 4032. Limiting rod; 4033. Fixed groove; 4034. Elastic element; DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0045] refer to Figures 1 to 16 As shown, a large F-number day and night lens comprises six lenses, wherein the six lenses are arranged in sequence along the axis direction, namely a first lens 1, a second lens 2, a third lens 4, a fourth lens 5, a fifth lens 6, and a sixth lens 7; an aperture stop 3 is arranged between the second lens 2 and the third lens 4; an optical imaging target surface 8 is arranged on one side of the sixth lens 7, and the optical imaging target surface 8 is arranged at the end of the lens; the first surface and the second surface of the second lens 2 and the second surface of the third lens 4 are aspherical surfaces; the lens adopts a positive+positive+negative+negative+positive+negative focal length combination, and the positive and negative lenses are arranged alternately.

[0046] The optical system composed of the above lenses has achieved the following optical indicators: focal length: f=40mm; F ​​number: 1.4; field of view: 2w≥41.11°, target size ≥30mm; total optical length L≤58mm; design wavelength: 400nm~900nm; weight: ≤40g; resolution: can match 1920×128012um white light low light imaging chip; can also be backward compatible with white light low light imaging chip with larger pixel size, such as matching 1280×1024, 13um white light low light imaging chip;

[0047] Depend on Figure 2 It is known that the maximum RMS value in the spot diagram is 8.255um<12um, which shows that the optical system can match the imaging chip with a pixel size of 12um;

[0048] Depend on Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 It is known that the optical system has excellent imaging quality;

[0049] Depend on Figure 8 , Fig. 9 , Fig.10 It is known that the minimum MTF value of the optical system at the line logarithm 42lp / mm under high and low temperature (-50℃~+60℃) environment is ≥0.42, so the system can be applied to high and low temperature (-50℃~+60℃) environment;

[0050] This lens has about 6 fewer lenses than traditional lenses of the same type, is about 60% lighter, and about 50% shorter in length. The mass production cost is expected to be reduced by about 50%, and the imaging quality will be improved by about 40%. It can meet the consumer trend of cheap, easy-to-use, small in size, and light in weight.

[0051] In order to adapt to various environments, a salt-fog resistant high-efficiency anti-reflection film is coated on the first surface of the first lens 1;

[0052] The first lens 1 of the present invention has positive refractive power, and the first surface is convex and the second surface is concave;

[0053] The second lens 2 of the present invention has positive refractive power, and the first surface is convex and the second surface is concave;

[0054] The third lens 4 of the present invention has negative optical power, and the first surface is concave, and the second surface is concave;

[0055] The fourth lens 5 of the present invention has negative optical power, and the first surface is concave, and the second surface is concave;

[0056] The fifth lens 6 of the present invention has positive refractive power, and the first surface is convex, and the second surface is convex;

[0057] The sixth lens element 7 of the present invention has negative refractive power, and has a first surface that is concave and a second surface that is concave.

[0058] The lens materials of the present invention are: H-ZK11, D-ZK3, D-ZK3, H-ZK11, H-ZF88, H-ZF52;

[0059] Further, aspheric surfaces are placed on the first and second surfaces of the second lens 2 and the second surface of the third lens 4;

[0060] Furthermore, the ratio of focal length to optical length is: 0.65<f / L<0.75.

[0061] Other data of the lens are shown in Table 1.

[0062] Table 1 Lens data table

[0063] Surface number Face type Radius of curvature thickness Material Remark S1 Spherical 30≤r≤35 5 H-ZK11 First lens S2 Spherical 50≤r≤55 5.7 S3 Aspheric 40≤r≤45 3.7 D-ZK3 Second lens S4 Aspheric 60≤r≤65 6.0 S5 (aperture stop) flat ∞ 3.95 S6 Spherical -90≤r≤-85 2.3 D-ZK3 The third lens S7 Aspheric 60≤r≤65 4.41 S8 Spherical -550≤r≤-540 2.2 H-ZK11 The fourth lens S9 Spherical 25≤r≤30 7.38 S10 Spherical 80≤r≤85 3.6 H-ZF88 Fifth lens S11 Spherical -120≤r≤-115 1.5 S12 Spherical -50≤r≤-45 2.5 H-ZF52 The sixth lens S13 Spherical 70≤r≤75 8.45 S14 (imaging surface) flat ∞ 0

[0064] The aspheric formula used by S3, S4, and S7 is:

[0065]

[0066] Where Z represents the aspheric surface sag, c represents the vertex curvature radius, k represents the conic section coefficient, A, B, C, D represent the aspheric surface coefficients, and r represents the radial coordinate on the aspheric surface.

[0067] The aspheric parameters of S3, S4 and S7 are shown in Table 2.

[0068] Table 2 Aspheric parameters of S3, S4, S7

[0069] Surface number k A B C D S3 2.021 -7.613e-6 -3.281e-10 -5.232e-11 -4.972e-14 S4 10 -2.836e-6 1.021e-8 -8.504e-11 1.3e-14 S7 -0.011 -5.044e-9 -4.248e-12 2.175e-14 1.634e-16

[0070] In the present invention, the lens thickness and spacing accuracy requirements are ±0.03mm, the lens center deviation accuracy is 1′, the aperture number is 3, the local aperture number is 0.5, the aspheric surface pv value is 1um, the rms value is 0.15um, the lens diameter tolerance is f7, and the lens body hole diameter tolerance is H7. The above-mentioned precisions are general precision requirements in modern and contemporary processing, and mass production and assembly can be carried out under this precision condition.

[0071] Specifically, the lens material adopts a crown-crown-crown-crown-flint-flint material combination.

[0072] Specifically, the focal lengths of the first lens 1, the second lens 2, the third lens 4, the fourth lens 5, the fifth lens 6, and the sixth lens 7 respectively satisfy 140<f1<150, 170<f2<180, -70<f3<-60, -40<f4<-30, 50<f5<60, -40<f6<-30, where f1, f2, f3, f4, f5, and f6 are the focal lengths of the first lens 1, the second lens 2, the third lens 4, the fourth lens 5, the fifth lens 6, and the sixth lens 7, respectively.

[0073] Specifically, the focal length f1 of the lens and the focal length f of the lens satisfy the following conditions: 3.5<f1 / f<3.75, 4.25<f2 / f<4.5, -1.75<f3 / f<-1.5, -1<f4 / f<-0.75, 1.25<f5 / f<1.5, -1<f6 / f<-0.75, where f1, f2, f3, f4, f5, f6 are the focal length values ​​of the first lens 1, the second lens 2, the third lens 4, the fourth lens 5, the fifth lens 6, and the sixth lens 7 respectively, and f is the focal length of the lens.

[0074] Specifically, the first lens 1, the second lens 2, the third lens 4, the fourth lens 5, the fifth lens 6, and the sixth lens 7 are respectively clamped by a lens clamp, which includes a shell 10, a control rod 20, a transmission member 30 and a clamping assembly 40. A mounting cavity 102 is provided inside the shell 10, and a through hole is provided in the middle of the shell 10. A dust ring 101 is provided on one side of the shell 10, a through hole 103 is provided above the shell 10, and a control rod 20 is coaxially provided in the through hole 103. The control rod 20 is coaxially provided with a transmission member 30. The control rod 20 rotates to drive the transmission member 30 to move synchronously. The clamping assembly 40 is connected to one side of the transmission member 30, and the clamping assembly 40 is provided in the mounting cavity 102. When the lens is assembled, the control rod 20 rotates to drive the transmission member 30 to rotate, and the transmission member 30 rotates to drive the clamping assembly 40 to expand or contract, so that the lens can be clamped stably to avoid damage to the corners of the lens.

[0075] Specifically, the transmission member 30 includes a driving gear 301 and a driven gear ring 302. The driving gear 301 is coaxially arranged with the control rod 20, and the driving gear 301 is rotatably arranged in the installation cavity 102. The driven gear ring 302 is arranged on the clamping assembly 40, and the driving gear 301 and the driven gear ring 302 are meshed with each other. The control rod 20 rotates to drive the driving gear 301 to rotate. Through the meshing of the driving gear 301 and the driven gear ring 302, the driving gear 301 drives the clamping assembly 40 to expand or contract.

[0076] Specifically, the control rod 20 includes a locking piece 201 and a threaded end 202, and the control rod 20 is rotatably arranged with the through hole 103, one end of the control rod 20 is provided with the threaded end 202, and the other end of the control rod 20 is provided with a threaded groove matching the threaded end 202, the locking piece 201 is arranged on the outer circumferential surface of the control rod 20, and the control rod 20 drives the driving gear 301 to rotate through the locking piece 201.

[0077] Specifically, the locking member 201 includes a movable sleeve 2011, a connecting spring 2012 and a locking block 2013. A mounting groove is provided on the control rod 20, and an annular groove 3011 is provided on the driving gear 301, and a magnet 3012 is arranged in the annular groove 3011. A pop-up outlet of the locking block 2013 is arranged near the annular groove 3011 in the mounting groove, and a movable sleeve 2011 is slidably arranged in the mounting groove. A plurality of connecting springs 2012 are arranged in an annular array near one end of the annular groove 3011 of the movable sleeve 2011, one end of the connecting spring 2012 is fixedly connected to the movable sleeve 2011, and the other end of the connecting spring 2012 is connected to the locking block 2013. The movable sleeve 2011 moves so that the locking block 2013 fits with the magnet 3012. At this time, the rotation of the control rod 20 drives the driving gear 301 to move synchronously.

[0078] Specifically, the clamping assembly 40 includes a fixed disk 401, a driving disk 402 and a clamping block 403. One side of the fixed disk 401 is fixedly connected to the installation cavity 102, and a limiting groove 4011 is provided in an annular array on the fixed disk 401. A driving disk 402 is provided on the side of the fixed disk 401 away from the inner wall of the installation cavity 102. A driving groove 4021 is provided in an annular array on the driving disk 402, and a plurality of clamping blocks 403 are provided between the driving disk 402 and the fixed disk 401. A driving rod 4031 is provided at one end of the clamping block 403, and a limiting rod 4032 is provided at the other end of the clamping block 403. A fixing groove 4033 for fixing the lens is provided in the middle of the clamping block 403, and an elastic element 4034 is installed in the fixing groove 4033.

[0079] An imaging method for a large F-number day and night lens, the specific steps are as follows:

[0080] Step 1: The operator first takes out the lens, and then places the lens in the fixing groove 4033 provided on the clamping block 403. The elastic element 4034 provided in the fixing groove 4033 can prevent the corners of the lens from being damaged;

[0081] Step 2: During the lens clamping process, the operator first pushes the movable sleeve 2011, and the movable sleeve 2011 drives the locking block 2013 to move into the annular groove 3011 provided on the driving gear 301. After the locking block 2013 and the annular groove 3011 are completely overlapped, the elastic potential energy of the connecting spring 2012 causes the locking block 2013 to fit into the annular groove 3011 of the driving gear 301.

[0082] Step 3: The locking block 2013 is adsorbed to the annular groove 3011 by the magnet 3012 in the annular groove 3011. At this time, the operator rotates the control rod 20, and the rotation of the control rod 20 drives the driving gear 301 to move coaxially. The driving gear 301 drives the driven gear ring 302 to rotate. The rotation of the driven gear ring 302 drives the clamping assembly 40 to center, clamp and fix the lens;

[0083] Step 4: After the lens is fixed, if multiple lenses need to be connected in series, the threaded end 202 at one end of the control rod 20 can be fixed to the threaded groove of another lens clamp control rod 20, so that multiple lenses can be connected in series. At the same time, the dust ring 101 can prevent dust from entering the connection between multiple clamps.

[0084] Working process and principle: in the initial state, the unassembled lens fixture is not unfolded. The operator first places the lens in the fixing groove 4033 of the clamping block 403. Since the fixing groove 4033 is provided with an elastic element 4034, there is no need to worry about the corners of the lens being damaged or worn. Then the operator pushes the moving sleeve 2011 provided on the control rod 20. The moving sleeve 2011 moves so that the locking block 2013 provided at one end of the moving sleeve 2011 moves. When the moving sleeve 2011 moves to the annular groove 3011 provided on the driving gear 301, the locking block 2013 is elastically connected to the spring 2012. The potential energy can push the locking block 2013 into the annular groove 3011. When the locking block 2013 is stuck in the annular groove 3011, the magnet 3012 arranged in the annular groove 3011 can adsorb the locking block 2013. At this time, the locking block 2013 and the annular groove 3011 attract each other. The operator can rotate the control rod 20, and the rotation of the control rod 20 drives the driving gear 301 to rotate. Since the driving gear 301 and the driven gear ring 302 are meshed with each other, and the driven gear ring 302 is coaxially fixedly connected with the driving disk 402, the driving gear 301 drives the driving disk 402 to rotate, and the driving disk 402 rotates through the driving groove 4021 squeezes the driving rod 4031 set at one end of the clamping block 403, so that the limiting rod 4032 on the other side of the clamping block 403 moves in the limiting groove 4011 on the fixing plate 401. At this time, the clamping block 403 shrinks toward the center of the fixing plate 401, so that the lens in the fixing groove 4033 moves toward the center position of the installation cavity 102. When the clamping block 403 is completely shrunk, the lens can be fixed by multiple clamping blocks 403, so as to avoid the lens from shaking or being out of the center during use. After the lens is fixed, the operator can pull the moving sleeve 2011 so that the locking block 2013 is not aligned with the driving gear 301. The control rod 20 is locked and then rotated to connect the control rod 20 with another lens clamp control rod 20. The threaded end 202 on the control rod 20 cooperates with the spiral groove of the other control rod 20 to fix the two lens clamps, thereby realizing the series connection between multiple lenses and making the central axes of the multiple lenses in a straight line. At the same time, the dust ring 101 on one side of the outer shell 10 can reduce the gap between the lens clamps after series connection, thereby preventing the gap between the lens clamps from being too large, causing dust in the external environment to enter the lens clamp, thereby preventing dust from adhering to the lens surface and affecting the imaging result of the lens.

[0085] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A large F number day and night lens, characterized in that: The lens comprises six lenses, wherein the six lenses are arranged in sequence along the axis direction, namely, a first lens (1), a second lens (2), a third lens (4), a fourth lens (5), a fifth lens (6), and a sixth lens (7); an aperture stop (3) is arranged between the second lens (2) and the third lens (4); an optical imaging target surface (8) is arranged on one side of the sixth lens (7), and the optical imaging target surface (8) is arranged at the end of the lens; the first surface and the second surface of the second lens (2) and the second surface of the third lens (4) are aspherical surfaces; the lens adopts a positive+positive+negative+negative+positive+negative focal length combination, and the positive and negative lenses are arranged alternately.

2. The large F number day and night lens according to claim 1, characterized in that: The lens material adopts a crown-crown-crown-crown-flint-flint material combination.

3. The large F number day and night lens according to claim 1, characterized in that: The focal lengths of the first lens (1), the second lens (2), the third lens (4), the fourth lens (5), the fifth lens (6) and the sixth lens (7) respectively satisfy 140<f1<150, 170<f2<180, -70<f3<-60, -40<f4<-30, 50<f5<60, -40<f6<-30, wherein f1, f2, f3, f4, f5 and f6 are the focal lengths of the first lens (1), the second lens (2), the third lens (4), the fourth lens (5), the fifth lens (6) and the sixth lens (7) respectively.

4. The large F number day and night lens according to claim 3, characterized in that: The focal length f1 of the lens and the focal length f of the lens meet the following conditions: 3.5<f1 / f<3.75, 4.25<f2 / f<4.5, -1.75<f3 / f<-1.5, -1<f4 / f<-0.75, 1.25<f5 / f<1.5, -1<f6 / f<-0.75, wherein f1, f2, f3, f4, f5, f6 are the focal length values ​​of the first lens (1), the second lens (2), the third lens (4), the fourth lens (5), the fifth lens (6), and the sixth lens (7), respectively, and f is the focal length of the lens.

5. The large F number day and night lens according to claim 1, characterized in that: The first lens (1), the second lens (2), the third lens (4), the fourth lens (5), the fifth lens (6) and the sixth lens (7) are respectively clamped by a lens clamp, the lens clamp comprising a housing (10), a control rod (20), a transmission member (30) and a clamping assembly (40), a mounting cavity (102) is provided inside the housing (10), a through hole is provided in the middle of the housing (10), a dustproof ring (101) is provided on one side of the housing (10), and a through hole (103) is provided on the top of the housing (10), A control rod (20) is coaxially arranged in the through hole (103), and a transmission member (30) is coaxially arranged in the control rod (20). The control rod (20) rotates to drive the transmission member (30) to move synchronously. A clamping assembly (40) is connected to one side of the transmission member (30). The clamping assembly (40) is arranged in the installation cavity (102). When the lens is assembled, the control rod (20) rotates to drive the transmission member (30) to rotate, and the transmission member (30) rotates to drive the clamping assembly (40) to expand or contract, so that the lens can be clamped stably and damage to the corners of the lens is avoided.

6. The large F number day and night lens according to claim 5, characterized in that: The transmission member (30) comprises a driving gear (301) and a driven gear ring (302); the driving gear (301) is coaxially arranged with the control rod (20), and the driving gear (301) is rotatably arranged in the installation cavity (102); the driven gear ring (302) is arranged on the clamping assembly (40), and the driving gear (301) and the driven gear ring (302) are meshed with each other; the control rod (20) rotates to drive the driving gear (301) to rotate; through the meshing of the driving gear (301) and the driven gear ring (302), the driving gear (301) drives the clamping assembly (40) to expand or contract.

7. The large F number day and night lens according to claim 4, characterized in that: The control rod (20) comprises a locking piece (201) and a threaded end (202), and the control rod (20) is rotatably arranged with the through hole (103), one end of the control rod (20) is provided with the threaded end (202), and the other end of the control rod (20) is provided with a threaded groove matched with the threaded end (202), the locking piece (201) is arranged on the outer circumferential surface of the control rod (20), and the control rod (20) drives the driving gear (301) to rotate through the locking piece (201).

8. The large F number day and night lens according to claim 7, characterized in that: The locking member (201) comprises a movable sleeve (2011), a connecting spring (2012) and a locking block (2013); a mounting groove is provided on the control rod (20); an annular groove (3011) is provided on the driving gear (301), and a magnet (3012) is arranged in the annular groove (3011); an ejection outlet of the locking block (2013) is arranged near the annular groove (3011); and the movable sleeve (2011) is slidably arranged in the mounting groove. A plurality of connecting springs (2012) are arranged in an annular array at one end of the movable sleeve (2011) close to the annular groove (3011), one end of the connecting spring (2012) is fixedly connected to the movable sleeve (2011), and the other end of the connecting spring (2012) is connected to a locking block (2013). The movable sleeve (2011) moves so that the locking block (2013) fits with the magnet (3012), and at this time, the control rod (20) rotates to drive the driving gear (301) to move synchronously.

9. The large F number day and night lens according to claim 8, characterized in that: The clamping assembly (40) comprises a fixed disk (401), a driving disk (402) and a clamping block (403); one side of the fixed disk (401) is fixedly connected to the mounting cavity (102); a limiting groove (4011) is provided in an annular array on the fixed disk (401); a driving disk (402) is provided on a side of the fixed disk (401) away from the inner wall of the mounting cavity (102); a driving groove (4021) is provided in an annular array on the driving disk (402); a plurality of clamping blocks (403) are provided between the driving disk (402) and the fixed disk (401); a driving rod (4031) is provided at one end of the clamping block (403); a limiting rod (4032) is provided at the other end of the clamping block (403); a fixing groove (4033) for fixing a lens is provided in the middle of the clamping block (403); an elastic element (4034) is installed in the fixing groove (4033).

10. An imaging method for a large F-number day and night lens, characterized in that: The specific steps are as follows: Step 1: The operator first takes out the lens, and then places the lens in a fixing groove (4033) provided on the clamping block (403). The elastic element (4034) provided in the fixing groove (4033) can prevent the corners of the lens from being damaged; Step 2: During the lens clamping process, the operator first pushes the movable sleeve (2011), and the movable sleeve (2011) drives the locking block (2013) to move into the annular groove (3011) provided on the driving gear (301). After the locking block (2013) and the annular groove (3011) are completely overlapped, the elastic potential energy of the connecting spring (2012) causes the locking block (2013) to fit into the annular groove (3011) of the driving gear (301). Step 3: The locking block (2013) is adsorbed to the annular groove (3011) by the magnet (3012) in the annular groove (3011). At this time, the operator rotates the control rod (20), and the rotation of the control rod (20) drives the driving gear (301) to move coaxially, and the driving gear (301) drives the driven gear ring (302) to rotate. The rotation of the driven gear ring (302) drives the clamping assembly (40) to center, clamp and fix the lens; Step 4: After the lens is fixed, if multiple lenses need to be connected in series, the threaded end (202) at one end of the control rod (20) can be fixed to the threaded groove of another lens clamp control rod (20), so that multiple lenses can be connected in series. At the same time, the dustproof ring (101) can prevent dust from entering the connection between multiple clamps.

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