A miniature wide-angle lens

Abstract

The utility model discloses a kind of miniature wide-angle lenses, it includes first lens, second lens, third lens, fourth lens, fifth lens, sixth lens and seventh lens sequentially distributed from object side to image side along optical axis, wherein: first lens is the convex-concave lens with negative optical power, wherein, the first surface of first lens close to object side is convex, and the second surface close to image side is concave;Second lens is the double convex lens with positive optical power;Third lens is the double concave lens with negative optical power;Fourth lens is the convex-concave lens with positive optical power;Fifth lens is the double convex lens with positive optical power;Sixth lens is the convex-concave lens with positive optical power;Seventh lens is the flat lens with positive optical power.In the utility model, the optical structure of seven glass lenses is used in the miniature wide-angle lens, to reduce the overall volume of miniature wide-angle lens.

Description

TECHNICAL FIELD

[0001] The utility model relates to technical field of lens especially relates to a miniature wide-angle lens. BACKGROUND

[0002] With the rapid development of modern science and technology, security monitoring technology is more and more widely used in various fields. From public places such as squares, warehouses, to residential areas, schools and other living areas, to the border and important facilities and other key areas, security monitoring plays an indispensable role. In the security monitoring system, the lens as the key supporting product of the camera, its quality and performance directly affect the clarity of the monitoring picture and the monitoring efficiency. In the existing monitoring facilities on the market, the related types of lenses have a large number of glass lenses, resulting in a large volume of lens barrel, which cannot meet the needs of consumers for small volume monitoring equipment. SUMMARY

[0003] The technical problem to be solved by the utility model is to provide a miniature wide-angle lens to solve the problem of large volume of the existing wide-angle lens.

[0004] In order to solve the above technical problem, the utility model adopts the technical scheme of a miniature wide-angle lens, which comprises first lens, second lens, third lens, fourth lens, fifth lens, sixth lens and seventh lens distributed along the optical axis from the object side to the image side, wherein:

[0005] The first lens is a convex-concave lens with negative focal length, wherein the first curve of the first lens close to the object side is convex, and the second curve close to the image side is concave;

[0006] The second lens is a double convex lens with positive focal length;

[0007] The third lens is a double concave lens with negative focal length;

[0008] The fourth lens is a convex-concave lens with positive focal length, wherein the first curve of the fourth lens close to the object side is concave, and the second curve close to the image side is convex;

[0009] The fifth lens is a double convex lens with positive focal length;

[0010] The sixth lens is a convex-concave lens with positive focal length, wherein the first curve of the sixth lens close to the object side is concave, and the second curve close to the image side is convex;

[0011] The seventh lens is a flat lens with positive focal length.

[0012] Furthermore, in the miniature wide-angle lens described in this utility model, the radius of curvature of the first surface of the second lens is a positive value, and the radius of curvature of the second surface of the second lens is a negative value, wherein the absolute values ​​of the radii of curvature of the first surface and the second surface of the second lens are the same.

[0013] Furthermore, in the miniature wide-angle lens of this utility model, the radius of curvature of the second surface of the fifth lens is negative, and the radius of curvature of the first surface of the sixth lens is negative, wherein the radius of curvature of the second surface of the fifth lens and the first surface of the sixth lens are the same.

[0014] Furthermore, in the miniature wide-angle lens described in this utility model, the miniature wide-angle lens must satisfy the following condition:

[0015] Tan(Semi-FOV) > TTL / (2×f)

[0016] 17 < (f23 × f45) / (D2 × D3) < 22

[0017] 8.5 < (f45 × f56) / (D4 × D56) < 9.0

[0018] Where Tan(Semi-FOV) represents the tangent of Semi-FOV, Semi-FOV is the maximum half field of view of the micro wide-angle lens, TTL is the total optical length of the micro wide-angle lens, and f is the equivalent focal length of the micro wide-angle lens;

[0019] Wherein, f23 is the equivalent focal length of the second and third lenses; f45 is the equivalent focal length of the fourth and fifth lenses; D2 is the center thickness of the second lens on the optical axis; and D3 is the center thickness of the third lens on the optical axis.

[0020] Wherein, f56 is the equivalent focal length of the fifth and sixth lenses; D4 is the center thickness of the fourth lens on the optical axis; and D56 is the total center thickness of the fifth and sixth lenses on the optical axis.

[0021] Furthermore, in the miniature wide-angle lens described in this utility model, the first lens and the second lens satisfy the following relationship:

[0022] 0.9<|f1 / f |<1.0; 0.24<|L1 / f1 |<0.3, 0.2<|D1 / f1 |<0.3;

[0023] 1.2 < |f2 / f1| < 1.3; 0.02 <L2 / f2<0.08;0.6<D2 / f2<0.8

[0024] Wherein, f1 is the focal length of the first lens; f is the equivalent focal length of the micro wide-angle lens; L1 is the distance between the first lens and the second lens; D1 is the central thickness of the first lens on the optical axis; f2 is the focal length of the second lens; L2 is the distance between the second lens and the third lens; D2 is the central thickness of the second lens on the optical axis.

[0025] Further, in the micro wide-angle lens, the third lens satisfies the following relationship:

[0026] 1.8<|f3 / f |<1.9

[0027] 0.02<|L2 / f3|<0.05, 0.09<|D3 / f3|<0.13

[0028] Wherein, f3 is the focal length of the third lens; f is the equivalent focal length of the micro wide-angle lens; L2 is the distance between the second lens and the third lens; D3 is the central thickness of the third lens on the optical axis.

[0029] Further, in the micro wide-angle lens, the fourth lens and the fifth lens satisfy the following relationship:

[0030] 1.6<f4 / f<2.0, 20<f5 / f<23

[0031] 0.03<L3 / f<0.6, 0.3<D4 / f<0.5

[0032] Wherein, f4 is the focal length of the fourth lens; f is the equivalent focal length of the micro wide-angle lens; f5 is the focal length of the fifth lens; L3 is the distance between the third lens and the fourth lens; D4 is the central thickness of the fourth lens on the optical axis.

[0033] Further, in the micro wide-angle lens, the first lens, the fourth lens and the fifth lens are glass lenses of the same material.

[0034] Further, in the micro wide-angle lens, the second lens and the sixth lens are glass lenses with a refractive index greater than a first threshold value; the third lens is a glass lens with an Abbe number lower than a second threshold value.

[0035] Further, in the micro wide-angle lens, the fifth lens and the sixth lens are cemented lenses.

[0036] The micro wide-angle lens for safety monitoring has the advantages that only seven glass lenses are needed, the arrangement and combination of the seven glass lenses are adopted, the total optical length of the micro wide-angle lens can be maintained below 14mm in practical application, and the volume of the micro wide-angle lens is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 A lens group schematic diagram of the micro wide-angle lens in the embodiment one is provided.

[0038] Figure 2 A point column diagram of the micro wide-angle lens in the embodiment one is provided.

[0039] Figure 3 An astigmatism diagram of the micro wide-angle lens in the embodiment one is provided.

[0040] Figure 4 A distortion diagram of the micro wide-angle lens in the embodiment one is provided.

[0041] Figure 5 A spherical aberration diagram of the micro wide-angle lens in the embodiment one is provided.

[0042] Figure 6 A chromatic aberration diagram of the micro wide-angle lens in the embodiment one is provided.

[0043] Figure 7 A lens group schematic diagram of the micro wide-angle lens in the embodiment two is provided.

[0044] Figure 8 A point column diagram of the micro wide-angle lens in the embodiment two is provided.

[0045] Figure 9 An astigmatism diagram of the micro wide-angle lens in the embodiment two is provided.

[0046] Figure 10 A distortion diagram of the micro wide-angle lens in the embodiment two is provided.

[0047] Figure 11 A spherical aberration diagram of the micro wide-angle lens in the embodiment two is provided.

[0048] Figure 12 A chromatic aberration diagram of the micro wide-angle lens in the embodiment two is provided.

[0049] REFERENCE NUMERALS

[0050] 1, first lens;

[0051] 2. the second lens;

[0052] 3. the third lens;

[0053] 4. the fourth lens;

[0054] 5. the fifth lens;

[0055] 6. the sixth lens;

[0056] 7. the seventh lens. DETAILED DESCRIPTION

[0057] In order to make the technical content of the utility model, the purpose and effect realized be explained in detail, the following will be explained in combination with the embodiment and the drawings.

[0058] In the monitoring facilities on the existing market, the related types of lenses are all multi-piece structures. With the gradual increase in the number of lenses used, the volume of the lens also increases, and the design of the optical module mechanism is also becoming more and more strict, which cannot meet the needs of consumers for small-volume monitoring devices. Therefore, please refer to Figures 1 to 12 The utility model discloses a kind of miniature wide-angle lenses, it includes first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6 and seventh lens 7 sequentially distributed along optical axis from object side to image side, wherein:

[0059] The first lens is convex-concave lens with negative optical power, wherein the first curve of the first lens close to object side is convex, and the second curve close to image side is concave;

[0060] The second lens is biconvex lens with positive optical power; wherein the first curve of the second lens close to object side is convex, and the second curve close to image side is convex;

[0061] The third lens is biconcave lens with negative optical power; wherein the first curve of the third lens close to object side is concave, and the second curve close to image side is concave;

[0062] The fourth lens is convex-concave lens with positive optical power, wherein the first curve of the fourth lens close to object side is concave, and the second curve close to image side is convex;

[0063] The fifth lens is biconvex lens with positive optical power; wherein the first curve of the fifth lens close to object side is convex, and the second curve close to image side is convex;

[0064] The sixth lens is convex-concave lens with positive optical power, wherein the first curve of the sixth lens close to object side is concave, and the second curve close to image side is convex;

[0065] The seventh lens is a flat lens with positive focal power.

[0066] From the above description, the micro wide-angle lens of the utility model has the advantages that the micro wide-angle lens adopts the optical structure of seven glass lenses, and the total lens optical length can be maintained below 14mm in actual application.

[0067] It should be noted that, in the lens of the utility model, the surface close to the object side (i.e. the object side surface) is referred to as the first curved surface, and the surface close to the image side (i.e. the image side surface) is referred to as the second curved surface. In the lens design of the utility model, when determining the positive and negative values of the curvature radius of the lens curved surface, the direction of the lens towards the object side is the reference direction. When the curvature radius value of the first curved surface of the lens is positive, the first curved surface is convex relative to the direction towards the object side, and concave relative to the direction towards the image side. When the curvature radius value of the second curved surface is positive, the second curved surface is convex relative to the direction towards the object side, and concave relative to the direction towards the image side.

[0068] Further, in the micro wide-angle lens of the utility model, the curvature radius value of the first curved surface of the second lens is positive, and the curvature radius value of the second curved surface of the second lens is negative, wherein the absolute values of the curvature radius values of the first curved surface and the second curved surface of the second lens are the same.

[0069] In actual application, the first curved surface and the second curved surface of the first lens 1 have positive curvature radius values. The first curved surface of the second lens 2 has a positive curvature radius value, and the second curved surface has a negative curvature radius value, wherein the curvature radius values of the two curved surfaces are the same. The first curved surface of the third lens 3 has a negative curvature radius value, and the second curved surface has a positive curvature radius value. The first and second curved surfaces of the fourth lens 4 have negative curvature radius values. The first curved surface of the fifth lens 5 has a positive curvature radius value, and the second curved surface has a negative curvature radius value. The first curved surface of the sixth lens 6 has a negative curvature radius value, and the second curved surface has a positive curvature radius value. The curvature radius values of the second curved surface of the fifth lens 5 and the first curved surface of the sixth lens 6 are the same.

[0070] Further, in the micro wide-angle lens of the utility model, the curvature radius value of the second curved surface of the fifth lens is negative, and the curvature radius value of the first curved surface of the sixth lens is negative, wherein the curvature radius values of the second curved surface of the fifth lens and the first curved surface of the sixth lens are the same.

[0071] Further, in the micro wide-angle lens of the utility model, the micro wide-angle lens needs to satisfy the following conditional expression:

[0072] Tan (Semi-FOV) > TTL / (2 x f)

[0073] 17 < (f23 x f45) / (D2 x D3) < 22

[0074] 8.5 < (f45 x f56) / (D4 x D56) < 9.0

[0075] Tan (Semi-FOV) represents the tangent value of Semi-FOV, Semi-FOV is the maximum half field angle of the micro wide-angle lens, TTL is the total optical length of the micro wide-angle lens; f is the equivalent focal length of the micro wide-angle lens;

[0076] f23 is the equivalent focal length of the second lens 2 and the third lens 3; f45 is the equivalent focal length of the fourth lens 4 and the fifth lens 5; D2 is the central thickness of the second lens 2 on the optical axis; D3 is the central thickness of the third lens 3 on the optical axis;

[0077] f56 is the equivalent focal length of the fifth lens 5 and the sixth lens 6; D4 is the central thickness of the fourth lens 4 on the optical axis; D56 is the central total thickness of the fifth lens 5 and the sixth lens 6 on the optical axis.

[0078] As described above, the micro wide-angle lens of the utility model needs to meet the above three conditional expressions, wherein, the Tan (Semi-FOV) > TTL / (2 x f) conditional expression relates to the allowable value of the total height design of the micro wide-angle lens of the utility model, when the value difference of Tan (Semi-FOV) > TTL / (2 x f) is greater, the allowable value is lower. The above allowable value refers to the maximum deviation degree of some parameters (such as total height) that can be accepted during design. Tan (Semi-FOV) represents that the Tan coefficient is taken by the maximum half angle, which can obtain the design parameter of the ideal optical height of the micro wide-angle lens, and this parameter directly affects the setting of the lens thickness.

[0079] The (f23 x f45) / (D2 x D3) conditional expression relates to the upper limit value of the total height design of the micro wide-angle lens of the utility model, and the (f45 x f56) / (D4 x D56) conditional expression relates to the lower limit value of the total height design of the micro wide-angle lens of the utility model.

[0080] From the above description, through the above three conditional expressions, the total height of the micro wide-angle lens of the utility model is limited and constrained, so that the total optical length of the micro wide-angle lens of the utility model can be maintained below 14mm, meeting the needs of consumers for small volume monitoring equipment.

[0081] Further, the first lens 1 and the second lens 2 satisfy the following relationship formula in the micro wide-angle lens:

[0082] 0.9<|f1 / f |<1.0;0.24<|L1 / f1 |<0.3, 0.2<|D1 / f1 |<0.3;

[0083] 1.2<|f2 / f1 |<1.3;0.02<L2 / f2<0.08;0.6<D2 / f2<0.8

[0084] Wherein, f1 is the focal length of the first lens 1, f is the equivalent focal length of the micro wide-angle lens, L1 is the distance between the first lens 1 and the second lens 2, D1 is the central thickness of the first lens 1 on the optical axis, f2 is the focal length of the second lens 2, L2 is the distance between the second lens 2 and the third lens 3, and D2 is the central thickness of the second lens 2 on the optical axis.

[0085] From the above description, through the above relationship formula, the overall thickness of the first lens 1 and the second lens 2 can be better controlled, so that the total length of the finally prepared micro wide-angle lens is maintained below 14mm, and the volume of the micro wide-angle lens is reduced.

[0086] Further, the third lens 3 satisfies the following relationship formula in the micro wide-angle lens:

[0087] 1.8<|f3 / f |<1.9

[0088] 0.02<|L2 / f3|<0.05, 0.09<|D3 / f3|<0.13

[0089] Wherein, f3 is the focal length of the third lens 3, f is the equivalent focal length of the micro wide-angle lens, L2 is the distance between the second lens 2 and the third lens 3, and D3 is the central thickness of the third lens 3 on the optical axis.

[0090] From the above description, in order to control the thickness of the third lens 3, the third lens 3 is correspondingly set, so that the third lens 3 satisfies the following relationship formula: 0.02<|L2 / f3|<0.05, 0.09<|D3 / f3|<0.13, so that the thickness of the third lens 3 can be effectively controlled, so that the total length of the finally prepared micro wide-angle lens is maintained below 14mm, and the volume of the micro wide-angle lens is reduced.

[0091] Further, the fourth lens and the fifth lens 5 must satisfy the following relationship formula in the micro wide-angle lens:

[0092] 1.6 < f4 / f < 2.0, 20 < f5 / f < 23

[0093] 0.03 < L3 / f < 0.6, 0.3 < D4 / f < 0.5

[0094] Wherein, f4 is the focal length of the fourth lens 4; f is the equivalent focal length of the micro wide-angle lens; f5 is the focal length of the fifth lens 5; L3 is the distance between the third lens 3 and the fourth lens 4; D4 is the central thickness of the fourth lens 4 on the optical axis.

[0095] From the above description, in order to control the thickness of the fourth lens 4 and the fifth lens 5, the corresponding parameters of the fourth lens 4 and the fifth lens 5 satisfy the following relationship, that is, satisfy 0.03 < L3 / f < 0.6 and 0.3 < D4 / f < 0.5, so that the thickness of the fourth lens 4 and the fifth lens 5 can be effectively controlled, thereby ensuring that the total length of the finally prepared micro wide-angle lens can be maintained below 14mm, and the volume of the micro wide-angle lens is reduced.

[0096] Further, in the micro wide-angle lens, the first lens 1, the fourth lens 4 and the fifth lens 5 are glass lenses of the same material.

[0097] Further, in the micro wide-angle lens, the second lens 2 and the sixth lens 6 are glass lenses of a material having a refractive index greater than a first threshold value; and the third lens 3 is a glass lens having an Abbe number lower than a second threshold value.

[0098] In actual application, the second lens 2 and the sixth lens 6 are glass lenses of a high-refractive material (such as a material having a refractive index greater than or equal to 1.60), and the third lens 3 is a glass lens having a low Abbe number (such as an Abbe number lower than 30). It should be noted that the first threshold value and the second threshold value can be selected according to actual conditions, which are not limited herein.

[0099] In actual application, through the combination of high and low refractive lenses, the first lens, the fourth lens and the fifth lens are glass lenses of the same material; the second lens and the sixth lens are glass lenses of a high-refractive material, and the first lens, the second lens, the third lens and the fourth lens have positive and negative refractive powers, which can make the micro wide-angle lens of the present application achieve high relative brightness and high resolution, that is, improve the relative brightness and resolution of the micro wide-angle lens.

[0100] Further, in the micro wide-angle lens, the fifth lens 5 and the sixth lens 6 are cemented lenses.

[0101] Please refer to Figures 1 to 6The embodiment one of the utility model provides a kind of miniature wide-angle lens, it is applied to safety monitoring field, as shown in figure, the miniature wide-angle lens adopts seven glass lenses optical structure, specifically: the miniature wide-angle lens includes first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6 and seventh lens 7 sequentially distributed along optical axis from object side to image side, the total length of miniature wide-angle lens in the embodiment is maintained below 14mm.And the miniature wide-angle lens in the embodiment is arranged by high and low refractive lens combination, can reach the purpose of high relative brightness and high-definition resolution. Figure 1

[0102] For convenience of description, the inventor sequentially states the specific parameter settings (such as the thickness and size of glass lenses) of the miniature wide-angle lens in embodiment one.

[0103] Table 1 lists the parameters of the glass lenses corresponding to the curved surfaces in the miniature wide-angle lens in embodiment one.

[0104] Table 1.

[0105]

[0106] Note: OBJ represents the object plane; STOP represents the stop; IMA represents the image plane; EFFL represents the effective focal length; F / NO represents the F number (F-Number), also known as the relative aperture.

[0107] It should be noted that the thickness / gap corresponding to the thirteenth surface in Table 1 is the distance length of the optical back focal length in the miniature wide-angle lens of the utility model.

[0108] Correspondingly, Table 2 is the main optical parameters of the miniature wide-angle lens in embodiment one.

[0109] Table 2.

[0110]

[0111] Table 3 is the corresponding numerical values of the corresponding condition formula of the miniature wide-angle lens in embodiment one.

[0112] Table 3.

[0113]

[0114] Table 4 is the corresponding numerical values of the corresponding relationship formula of the miniature wide-angle lens in embodiment one.

[0115] Table 4.

[0116]

[0117] ​The lens shape and the lens properties of the wide-angle lens in the first embodiment are shown in Tables 1 to 4. The corresponding values in the corresponding conditions in Table 3 can be used to determine the length range and effect of the TTL. Based on the corresponding values in Table 3, the lens thickness (e.g., D1, D2) and the lens spacing distance (e.g., L1, L2) can be controlled by using the relationships in the above table to achieve the effect of miniaturization. Therefore, based on the corresponding values in Tables 1 to 4, it can be seen that the wide-angle lens in the first embodiment can achieve miniaturization.

[0118] Correspondingly, in order to further verify the optical performance of the wide-angle lens, such as the depth of field range and effect, the edge resolution, and the like, the RMS (Root Mean Square Radius) values, the astigmatism values, the spherical aberration values, and the chromatic aberration values of the wide-angle lens in the first embodiment are provided as follows.

[0119] Table 5 shows the RMS values of the wide-angle lens in the first embodiment.

[0120] Table 5.

[0121]

[0122] Table 6 shows the astigmatism values of the wide-angle lens in the first embodiment.

[0123] Table 6.

[0124]

[0125] Table 7 shows the spherical aberration values of the wide-angle lens in the first embodiment.

[0126] Table 7.

[0127]

[0128] Table 8 shows the chromatic aberration values of the wide-angle lens in the first embodiment.

[0129] Table 8.

[0130]

[0131] It should be noted that the RMS values mainly represent the degree of light focusing. The smaller the RMS values, the smaller the focusing point, and the better the depth of field range and effect. The astigmatism values mainly represent that the closer the red and blue wavelengths are to the main wavelength (green), the higher the image and color restoration, and the less likely the image of the photographed object is blurred. In addition, because the wide-angle lens usually has a problem of poor edge resolution (excessive distortion), the spherical aberration coefficient must be controlled to avoid excessive blurring of the edge image. The chromatic aberration values are used to control the convergence of the red, green, and blue wavelengths to reduce the occurrence of purple and green edges.

[0132] Based on the above disclosed contents in Tables 5-8, it is not difficult to see that the micro wide-angle camera prepared in Embodiment One has good optical performance. In actual applications, the edge effect of a general wide-angle lens is not good, such as without controlling the spherical aberration and the astigmatism, the edge effect is difficult to have a good performance, and according to the above spherical aberration values and pixel values of the micro wide-angle lens of Embodiment One, the edge effect of the micro wide-angle lens is better; in addition, the CRA of the wide-angle lens is usually large, such as matched with a small CRA sensor, the purple edge and green edge are prone to occur, at this time, the chromatic aberration can be used for control to avoid the phenomenon, and it can be seen from Table 8 that the chromatic aberration value is not much different from the ideal range, and the situation that the wide-angle lens has purple edge and green edge can be better controlled.

[0133] Please refer to Figures 7 to 12 Embodiment Two of the utility model provides a micro wide-angle lens, which is applied to the field of safety monitoring, such as Figure 7 As shown in the figure, the micro wide-angle lens adopts the optical structure of seven glass lenses, specifically: the micro wide-angle lens includes first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6 and seventh lens 7 distributed in order along the optical axis from the object side to the image side, the total length of the micro wide-angle lens in the embodiment is maintained below 14mm. Moreover, the micro wide-angle lens in the embodiment can achieve the purposes of high relative brightness and high-definition resolution through the combination of high and low refractive lenses.

[0134] For the convenience of description, the inventor sequentially describes the specific parameter settings (such as the thickness and size of the glass lens) of the micro wide-angle lens in Embodiment Two.

[0135] Table 9 lists the parameters of the glass lens corresponding to the surface in the micro wide-angle lens in Embodiment Two.

[0136] Table 9.

[0137]

[0138] Note: OBJ represents the object plane; STOP represents the stop; IMA represents the image plane; EFFL represents the effective focal length; F / NO represents the F number (F-Number), also known as the relative aperture.

[0139] It should be noted that the thickness / gap of the thirteenth surface in the above Table 9 is the distance length of the optical back focal length of the micro wide-angle lens of the utility model.

[0140] Table 10 is the main optical parameters of the micro wide-angle lens in Embodiment Two.

[0141] Table 10.

[0142]

[0143] Table 11 is the corresponding numerical values of the conditional formula of the miniature wide-angle lens in this embodiment two.

[0144] Table 11.

[0145]

[0146] Table 12 is the corresponding numerical values of the corresponding relationship formula of the miniature wide-angle lens in this embodiment two.

[0147] Table 12.

[0148]

[0149] The above Tables 9 to 12 give the lens shape and the properties of each lens of the miniature wide-angle lens in this embodiment two, and the corresponding numerical values of the conditional formula in the above Table 11 can be used to determine the length range and effect of the TTL, and based on the corresponding numerical values in the above Table 11, the lens thickness (such as D1, D2) and the lens spacing distance (such as L1, L2) can be controlled by the relationship formula in the above table to achieve the effect of miniaturization. Therefore, based on the corresponding numerical values of the above Tables 9 to 12, it can be seen that the optical wide-angle lens of this embodiment two can achieve miniaturization.

[0150] In addition, in combination with the data of the conditional formula Tan(Semi-FOV)>TTL / (2×f) in Table 3 of the above embodiment one and Table 11 of this embodiment two, the design tolerance of the above embodiment one is better than that of embodiment two.

[0151] Correspondingly, in order to further verify the optical performance of the miniature wide-angle lens, such as the depth of field range and effect, edge resolution, etc., and compare the performance of embodiments one and two in the above parameters, the RMS numerical value, the astigmatism numerical value, the spherical aberration numerical value and the chromatic aberration numerical value of the miniature wide-angle lens in this embodiment two are also provided, as follows.

[0152] Table 13 is the RMS numerical value of the miniature wide-angle lens in this embodiment two.

[0153] Table 13.

[0154]

[0155] Table 14 is the astigmatism numerical value of the miniature wide-angle lens in this embodiment two.

[0156] Table 14.

[0157]

[0158] Table 15 is the spherical aberration numerical value of the miniature wide-angle lens in this embodiment two.

[0159] Table 15.

[0160]

[0161] Table 16 is the chromatic aberration value of the wide-angle lens in the second embodiment.

[0162] Table 16.

[0163]

[0164] Based on the above disclosed contents in Tables 13-16, and compared with the corresponding parameters in the first embodiment, it can be known that: (1) from the RMS values in Table 5 of the first embodiment and Table 13 of the second embodiment, even though the aperture of the wide-angle lens in the first embodiment is larger than that in the second embodiment, the RMS value of the maximum half field angle 5 of the wide-angle lens in the first embodiment is still better than that in the second embodiment, and the RMS values of the half field angles 1-4 of the wide-angle lens in the first embodiment are not much different from those in the second embodiment, that is, the beam convergence and focusing of the first embodiment are better than those of the second embodiment, please refer to Figure 2 and Figure 8 for details. (2) from the astigmatism values in Table 6 of the first embodiment and Table 14 of the second embodiment, the main wavelength of the wide-angle lens of the utility model is 588 nm, the difference values of wavelength one and wavelength three in the S direction and wavelength two in the first embodiment are -7.6 um and -7.6 um respectively, and the difference values of wavelength one and wavelength three in the T direction and wavelength two in the first embodiment are 8.7 um and 0.4 um respectively; the difference values of wavelength one and wavelength three in the S direction and wavelength two in the second embodiment are 7.0 um and 7.0 um respectively, and the difference values of wavelength one and wavelength three in the T direction and wavelength two in the second embodiment are 12 um and 1.0 um respectively, from the data, the difference of the S direction offset number is not large, but the T direction of the first embodiment performs better, please refer to Figure 3 and Figure 9 for details. In the above, the three groups of curves in Figure 3 and Figure 9 are the corresponding curves of blue, green and red wavelengths, and because there are two directions of sub-five and arc loss, there are a total of six curves. (3) according to the spherical aberration values in Table 7 of the first embodiment and Table 15 of the second embodiment, the maximum difference value of the spherical aberration values of wavelength one, two and three of the wide-angle lens in the first embodiment is 27 um, and the maximum difference value of the spherical aberration values of wavelength one, two and three of the wide-angle lens in the second embodiment is 24 um, from the data, the second embodiment performs better than the first embodiment, but the difference is not large, please refer to Figure 5 and Figure 11 for details.(4) According to the chromatic aberration values in Table 8 in Embodiment 1 and Table 16 in Embodiment 2, the main wavelength of the micro wide-angle lens is 588nm, the difference values of wavelength one and wavelength three of the micro wide-angle lens in Embodiment 1 from the ideal value are -0.27um and -0.49um respectively, and the difference values of wavelength one and wavelength three of Embodiment 2 from wavelength two in the T direction are 1.50um and -0.33um respectively, from the data, the deviation of wavelength one and wavelength three of the micro wide-angle lens in Embodiment 1 is within 1um, but the deviation of wavelength one of Embodiment 2 is greater than 1um, please refer to Figure 6 and Figure 12 . Embodiments 1 and 2 are basically similar in design, and the optical performance is similar, and even the TTL performance of Embodiment 2 is better than that of Embodiment 1, but in the dispersion part, the value of wavelength one (blue light) of Embodiment 2 is close to twice the ideal SPOT size, which will greatly increase the risk of purple edge, and the purple edge phenomenon is difficult to solve by the rear-end software (DSP) in the image screen, so Embodiment 1 is preferred. In summary, the TTL and field angle design of Embodiment 2 is better than that of Embodiment 1, but the basic optical performance evaluation is still better than that of Embodiment 1, so Embodiment 1 is preferred.

[0165] In summary, the micro wide-angle lens provided by the utility model: the utility model provides a kind of micro wide-angle lens for safety monitoring, and the micro wide-angle lens adopts the optical structure of seven glass lenses, and the total length of micro wide-angle lens is maintained below 14mm, and is combined and arranged by high and low refractive lenses, to achieve the purpose of high relative brightness and high-definition resolution.

[0166] The above-mentioned is only the embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent transformation or direct or indirect application in related technical field using the contents of the utility model specification and drawings is also included in the patent protection range of the utility model.

Claims

1. A miniature wide-angle lens characterized by comprising: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are sequentially arranged along the optical axis from the object side to the image side, wherein: The first lens is a convex-concave lens with negative focal power, wherein the first curve close to the object side is convex, and the second curve close to the image side is concave; The second lens is a biconvex lens with positive focal power; The third lens is a biconcave lens with negative focal power; The fourth lens is a convex-concave lens with positive focal power, wherein the first curve close to the object side is concave, and the second curve close to the image side is convex; The fifth lens is a biconvex lens with positive focal power; The sixth lens is a convex-concave lens with positive focal power, wherein the first curve close to the object side is concave, and the second curve close to the image side is convex; The seventh lens is a flat lens with positive focal power.

2. The miniature wide-angle lens according to claim 1, characterized in that, The radius of curvature of the first curve of the second lens is a positive value, and the radius of curvature of the second curve of the second lens is a negative value, wherein the absolute values of the radii of curvature of the first curve and the second curve of the second lens are the same.

3. The miniature wide-angle lens according to claim 1, characterized in that, The radius of curvature of the second curve of the fifth lens is a negative value, and the radius of curvature of the first curve of the sixth lens is a negative value, wherein the radii of curvature of the second curve of the fifth lens and the first curve of the sixth lens are the same.

4. The mini wide-angle lens according to claim 1, characterized in that, The micro wide-angle lens satisfies the following conditions: Tan(Semi-FOV)> TTL / (2×f) 17<(f23×f45) / (D2×D3) <22 8.5 <(f45×f56) / (D4×D56) < 9.0 Tan(Semi-FOV) represents the tangent value of Semi-FOV, Semi-FOV is the maximum half field angle of the micro wide-angle lens, TTL is the total optical length of the micro wide-angle lens; f is the equivalent focal length of the micro wide-angle lens; f23 is the equivalent focal length of the second lens and the third lens; f45 is the equivalent focal length of the fourth lens and the fifth lens; D2 is the central thickness of the second lens on the optical axis; D3 is the central thickness of the third lens on the optical axis; f56 is the equivalent focal length of the fifth lens and the sixth lens; D4 is the central thickness of the fourth lens on the optical axis; D56 is the total central thickness of the fifth lens and the sixth lens on the optical axis.

5. The miniature wide-angle lens of claim 1, wherein The first lens and the second lens satisfy the following relationship: 0.9<|f1 / f |<1.0;0.24<|L1 / f1 |<0.3, 0.2<|D1 / f1 |<0.3; 1.2<|f2 / f1 |<1.3;0.02< L2 / f2 <0.08;0.6 < D2 / f2 <0.8 Wherein, f1 is the focal length of the first lens; f is the equivalent focal length of the micro wide-angle lens; L1 is the distance between the first lens and the second lens; D1 is the central thickness of the first lens on the optical axis; f2 is the focal length of the second lens; L2 is the distance between the second lens and the third lens; D2 is the central thickness of the second lens on the optical axis.

6. The mini wide-angle lens according to claim 1, characterized in that, The third lens satisfies the following relationship: 1.8<|f3 / f |<1.9 0.02<|L2 / f3|<0.05, 0.09< |D3 / f3|<0.13 Wherein, f3 is the focal length of the third lens; f is the equivalent focal length of the micro wide-angle lens; L2 is the distance between the second lens and the third lens; D3 is the central thickness of the third lens on the optical axis.

7. The mini wide-angle lens according to claim 1, characterized in that, The fourth lens and the fifth lens satisfy the following relationship: 1.6< f4 / f <2.0, 20< f5 / f <23 0.03< L3 / f <0.6, 0.3< D4 / f <0.5 Wherein, f4 is the focal length of the fourth lens; f is the equivalent focal length of the micro wide-angle lens; f5 is the focal length of the fifth lens; L3 is the distance between the third lens and the fourth lens; D4 is the central thickness of the fourth lens on the optical axis.

8. The miniature wide-angle lens of claim 1, wherein, The first lens, the fourth lens and the fifth lens are glass lenses of the same material.

9. The miniature wide-angle lens of claim 1, wherein, The second lens and the sixth lens are glass lenses with a refractive index greater than a first threshold value; the third lens is a glass lens with an Abbe number lower than a second threshold value.

10. The miniature wide-angle lens of claim 1, wherein, The fifth lens and the sixth lens are cemented lenses.

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