Optical lens

Abstract

The present invention relates to the field of optical lenses and discloses an optical lens. The optical lens comprises, in order from the object side to the image side along the optical axis: a first lens having positive focal power, whose object-side surface is convex and whose image-side surface is concave; a second lens having negative focal power, whose object-side surface is convex and whose image-side surface is concave; a third lens having negative focal power, whose object-side surface is concave and whose image-side surface is concave; an aperture; a fourth lens having positive focal power, whose object-side surface is concave and whose image-side surface is convex; and a fifth lens having positive focal power, whose object-side surface is convex and whose image-side surface is convex. The optical lens satisfies the following relationships: 0.1≤f5 / f≤2; 0.2≤(R9+R10) / (R9-R10)≤1.2; and 0.01≤d9 / TTL≤0.2. The optical lens of the present invention has good uniformity, a large depth of field, can correct aberrations, and improves imaging quality, among other excellent optical properties.

Description

Technical Field

[0001] The invention relates to the field of optical lenses, and in particular to an optical lens suitable for a dental impression instrument. Background Art

[0002] A digital oral impression system is a device used by medical institutions to scan a patient's oral cavity, capturing images of teeth and other tissues. The device, when used in conjunction with a computer, reconstructs a digital 3D model of the oral cavity. This digital 3D model can be used, for example, in the production of dental restorations.

[0003] At present, the optical components of the oral digital impression instrument based on binocular structure mainly consist of a projector and two imaging camera optical lenses, as shown in the attached figure. Figure 1 As shown, a light template with sinusoidal stripes is projected into the scene, and 2D images are captured by the left and right cameras. This system does not require projector calibration, only the binocular cameras. The calibrated camera internal and external parameters are then used to correct the 2D image pairs. Next, matching point pairs are found using the unique encoding in the light template and a region-based binocular matching algorithm. Finally, the coordinate system relationship is used to reconstruct a digital 3D model of the oral cavity.

[0004] However, due to the limited space inside the oral cavity, the operation and use of the above-mentioned equipment bring many inconveniences and difficulties. The camera lens needs to be as small as possible to facilitate use and operation. However, after solving the size problem, the imaging range of the optical lens currently used in oral digital impression devices has also been reduced accordingly, which also affects the image acquisition effect inside the oral cavity.

[0005] Therefore, there is an urgent need to provide an optical lens that is as small as possible while having a large imaging range, that is, a large depth of field. Summary of the Invention

[0006] In view of the above problems, the object of the present invention is to provide an optical lens with good uniformity, large depth of field, and the ability to correct aberrations and improve imaging quality.

[0007] To solve the above technical problems, an embodiment of the present invention provides an optical lens, characterized in that the optical lens comprises, in order from the object side to the image side along the optical axis:

[0008] The first lens has positive refractive power, its object-side surface is convex and its image-side surface is concave;

[0009] a second lens having negative optical power, the object-side surface of which is convex and the image-side surface of which is concave;

[0010] a third lens element having negative optical power, with a concave object-side surface and a concave image-side surface;

[0011] Aperture;

[0012] a fourth lens element having positive optical power, whose object-side surface is concave and whose image-side surface is convex;

[0013] and a fifth lens having positive refractive power, the object-side surface of which is convex and the image-side surface of which is convex;

[0014] The focal length of the optical lens is defined as f, the focal length of the fifth lens element is defined as f5, the radius of curvature of the object side surface of the fifth lens element is defined as R9, the radius of curvature of the image side surface of the fifth lens element is defined as R10, the axial thickness of the fifth lens element is defined as d9, and the total optical length of the optical lens element is defined as TTL. The optical lens element satisfies the following relationship:

[0015] 0.1≤f5 / f≤2;

[0016] 0.2≤(R9+R10) / (R9-R10)≤1.2;

[0017] 0.01≤d9 / TTL≤0.2.

[0018] Preferably, the optical power of the first lens is φ1, the refractive index of the first lens is nd1, the curvature radius of the object side surface of the first lens is R1, the curvature radius of the image side surface of the first lens is R2, and the axial thickness of the first lens is d1;

[0019] The optical power of the second lens is φ2, the refractive index of the second lens is nd2, the radius of curvature of the object side surface of the second lens is R3, the radius of curvature of the image side surface of the second lens is R4, and the axial thickness of the second lens is d3;

[0020] The optical power of the third lens is φ3, the refractive index of the third lens is nd3, the curvature radius of the object side of the third lens is R5, the curvature radius of the image side of the third lens is R6, and the axial thickness of the third lens is d5;

[0021] The optical power of the fourth lens is φ4, the refractive index of the fourth lens is nd4, the curvature radius of the object side surface of the fourth lens is R7, the curvature radius of the image side surface of the fourth lens is R8, and the axial thickness of the fourth lens is d7;

[0022] The optical power of the fifth lens is φ5, the refractive index of the fifth lens is nd5, the curvature radius of the object side surface of the fifth lens is R9, the curvature radius of the image side surface of the fifth lens is R10, and the axial thickness of the fifth lens is d9;

[0023] And the following relationship is satisfied:

[0024] φ1= ;

[0025] Φ2= ;

[0026] Φ3= ;

[0027] Φ4= ;

[0028] Φ5= .

[0029] Preferably, the optical lens satisfies the following relationship:

[0030] 0.05 / mm≤φ1≤0.1 / mm;

[0031] -0.15 / mm≤φ2≤-0.05 / mm;

[0032] -0.15 / mm≤φ3≤-0.1 / mm;

[0033] 0.05 / mm≤φ4≤0.1 / mm;

[0034] 0.05 / mm≤φ5≤0.1 / mm.

[0035] Preferably, the focal length of the first lens is f1, the focal length of the second lens is f2, the axial thickness of the fourth lens is d7, and the axial distance from the image side surface of the fourth lens to the object side surface of the fifth lens is d8, and the following relationship is satisfied:

[0036] 0.6≤f1 / f≤1.7;

[0037] -30mm≤f2≤0mm;

[0038] 1≤d7 / d8≤30.

[0039] Preferably, the optical lens satisfies the following relationship:

[0040] 0.9≤f1 / f≤1.55;

[0041] -15mm≤f2≤0mm;

[0042] 2≤d7 / d8≤19.

[0043] Preferably, the focal length of the second lens is f2; and the optical lens satisfies the following relationship:

[0044] -1.8≤f2 / f≤0;

[0045] 0.5≤(R3+R4) / (R3-R4)≤4;

[0046] 0.005≤d3 / TTL≤0.08.

[0047] Preferably, the focal length of the third lens is f3; and the optical lens satisfies the following relationship:

[0048] -1.2≤f3 / f≤0.7;

[0049] -1.5≤(R5+R6) / (R5-R6)≤0.85;

[0050] 0.01≤d5 / TTL≤0.05.

[0051] Preferably, the focal length of the fourth lens is f4, and the optical lens satisfies the following relationship:

[0052] 0.1≤f4 / f≤2;

[0053] 0.5≤(R7+R8) / (R7-R8)≤2.25;

[0054] 0.01≤d7 / TTL≤0.08.

[0055] Preferably, the optical lens satisfies the following relationship:

[0056] 0.1≤(R9+R10) / (R9-R10)≤0.95.

[0057] Preferably, the axial thickness of the first lens is d1, and the optical lens satisfies the following relationship:

[0058] 0.01≤d1 / TTL≤0.08.

[0059] The beneficial effects of the present invention are as follows: the optical lens according to the present invention has excellent optical characteristics, good uniformity, a large depth of field, can correct aberrations, and improve imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a schematic diagram of binocular structured light;

[0061] Figure 2 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present invention;

[0062] Figure 3 yes Figure 1 MTF curve diagram of the optical lens shown;

[0063] Figure 4 yes Figure 1 Schematic diagram of field curvature and distortion of the optical lens shown;

[0064] Figure 5 yes Figure 1 The lateral raster diagram of the optical lens shown;

[0065] Figure 6 2 is a schematic structural diagram of an optical lens according to a second embodiment of the present invention;

[0066] Figure 7 yes Figure 6 MTF curve diagram of the optical lens shown;

[0067] Figure 8 yes Figure 6 Schematic diagram of field curvature and distortion of the optical lens shown;

[0068] Figure 9 yes Figure 6 The lateral raster diagram of the optical lens shown;

[0069] Figure 10 1 is a schematic structural diagram of an optical lens according to a third embodiment of the present invention;

[0070] Figure 11 yes Figure 10 MTF curve diagram of the optical lens shown;

[0071] Figure 12 yes Figure 10 Schematic diagram of field curvature and distortion of the optical lens shown;

[0072] Figure 13 yes Figure 10 Lateral raster diagram of the optical lens shown. DETAILED DESCRIPTION

[0073] To make the objectives, technical solutions, and advantages of the present invention more apparent, various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in various embodiments of the present invention to facilitate a better understanding of the present invention. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present invention can still be implemented.

[0074] (First embodiment)

[0075] With reference to the accompanying drawings, the present invention provides an optical lens 10 . Figure 1The optical lens 10 according to the first embodiment of the present invention is shown. This optical lens 10 comprises five lenses. Specifically, along the optical axis, from the object side to the image side, the optical lens 10 comprises: a first lens L1, a second lens L2, a third lens L3, an aperture STO, a fourth lens L4, and a fifth lens L5. An optical element such as an optical filter GF may be positioned between the fifth lens L5 and the image plane Si. The aperture STO is located between the third and fourth lenses and includes several apertures for limiting the size of the incident light beam. The aperture STO's size and position play a decisive role in the clarity, accuracy, and brightness of the image ultimately produced by the optical lens.

[0076] In this embodiment, the first lens has positive optical power, its object-side surface is convex, and its image-side surface is concave; the second lens has negative optical power, its object-side surface is convex, and its image-side surface is concave; the third lens has negative optical power, its object-side surface is concave, and its image-side surface is concave; the fourth lens has positive optical power, its object-side surface is concave, and its image-side surface is convex; the fifth lens has positive optical power, its object-side surface is convex, and its image-side surface is convex.

[0077] The focal length of the overall optical lens 10 is defined as f, and the focal length of the first lens L1 is defined as f1. The following relationship is satisfied: 0.6 ≤ f1 / f ≤ 1.7. Within the specified range of the conditional expression, the ratio of the focal length of the first lens to the total focal length is defined. This conditional expression helps reduce system aberrations and facilitates the development of ultra-thin and wide-angle lenses. Preferably, 0.9 ≤ f1 / f ≤ 1.55 is satisfied.

[0078] The focal length of the second lens L2 is defined as f2, which satisfies the following relationship: -30mm≤f2≤0mm. This specifies the focal length of the second lens, helps correct system aberrations, and improves imaging quality. Preferably, -15mm≤f2≤0mm is satisfied.

[0079] Furthermore, the following relationship is satisfied: -1.8 ≤ f2 / f ≤ 0; this specifies the ratio of the focal length of the second lens element to the total focal length. By controlling the negative power of the second lens element L2 within a reasonable range, it is beneficial to correct aberrations of the optical system. Preferably, -1.2 ≤ f2 / f ≤ -0.2 is satisfied.

[0080] The focal length of the third lens L3 is defined as f3, satisfying the following relationship: -1.2 ≤ f3 / f ≤ 0.7. This specifies the ratio of the third lens focal length to the total focal length, ensuring that the system has good imaging quality and low sensitivity within this range. Preferably, -0.91 ≤ f3 / f ≤ 0.12 is satisfied.

[0081] The focal length of the fourth lens L4 is defined as f4, satisfying the following relationship: 0.1 ≤ f4 / f ≤ 2. This specifies the ratio of the fourth lens focal length to the total focal length, ensuring that the system has good imaging quality and low sensitivity within this range. Preferably, 0.456 ≤ f4 / f ≤ 1.539 is satisfied.

[0082] The focal length of the fifth lens element is defined as f5, satisfying the following relationship: 0.1 ≤ f5 / f ≤ 2. Within the specified range of this conditional expression, the ratio of the fifth lens focal length to the total focal length is specified. By properly distributing the focal lengths within this range, the system achieves better imaging quality and lower sensitivity. Preferably, 0.53 ≤ f5 / f ≤ 1.5 is satisfied.

[0083] The on-axis curvature radius of the object-side surface of the first lens is defined as R1, and the on-axis curvature radius of the image-side surface of the first lens is defined as R2, satisfying the following relationship: -2.5 ≤ (R1 + R2) / (R1 - R2) ≤ 0.5. The shape of the first lens L1 is appropriately controlled so that the first lens L1 can effectively correct system spherical aberration. Preferably, -1.921 ≤ (R1 + R2) / (R1 - R2) ≤ -0.392 is satisfied.

[0084] The on-axis curvature radius of the object side of the second lens is defined as R3, and the on-axis curvature radius of the image side of the second lens is defined as R4, satisfying the following relationship: 0.5 ≤ (R3 + R4) / (R3 - R4) ≤ 4. This specifies the shape of the second lens. Within this range, as lenses move towards ultra-thin and wide-angle lenses, it is beneficial to correct on-axis chromatic aberration. Preferably, 1.396 ≤ (R3 + R4) / (R3 - R4) ≤ 3.254 is satisfied.

[0085] The on-axis radius of curvature of the object side of the third lens is defined as R5, and the on-axis radius of curvature of the image side of the third lens is defined as R6, satisfying the following relationship: -1.5 ≤ (R5 + R6) / (R5 - R6) ≤ 0.85. This specifies the shape of the third lens, which can mitigate the degree of light deflection through the lens and effectively reduce aberrations. Preferably, -1.12 ≤ (R5 + R6) / (R5 - R6) ≤ 0.079.

[0086] The on-axis curvature radius of the object side of the fourth lens is defined as R7, and the on-axis curvature radius of the image side of the fourth lens is defined as R8, satisfying the following relationship: 0.5 ≤ (R7 + R8) / (R7 - R8) ≤ 2.25. This specifies the shape of the fourth lens, helping to minimize light deflection and aberrations. Preferably, 0.976 ≤ (R7 + R8) / (R7 - R8) ≤ 1.913.

[0087] The on-axis curvature radius of the object-side surface of the fifth lens is defined as R9, and the on-axis curvature radius of the image-side surface of the fifth lens is defined as R10, satisfying the following relationship: 0.2 ≤ (R9 + R10) / (R9 - R10) ≤ 1.2. This defines the shape of the fifth lens, helping to minimize light deflection and aberrations. Preferably, 0.1 ≤ (R9 + R10) / (R9 - R10) ≤ 0.95.

[0088] The axial thickness of the first lens is defined as d1, and the total optical length of the optical lens is defined as TTL. The following relationship is satisfied: 0.01≤d1 / TTL≤0.08. When this condition is satisfied, ultra-thinness is achieved. Preferably, 0.025≤d1 / TTL≤0.063 is satisfied.

[0089] The axial thickness of the second lens is defined as d3, which satisfies the following relationship: 0.005≤d3 / TTL≤0.08. When it is within the range specified by the conditional expression, it is conducive to achieving ultra-thinness. Preferably, it satisfies 0.019≤d3 / TTL≤0.047.

[0090] The axial thickness of the third lens is defined as d5, which satisfies the following relationship: 0.01≤d3 / TTL≤0.05. When this condition is within the specified range, it is conducive to achieving ultra-thinness. Preferably, 0.019≤d5 / TTL≤0.047 is satisfied.

[0091] The aperture STO can reduce the risk of stray light or vignetting generated by the optical lens 10 and improve the performance of the optical lens 10.

[0092] The on-axis thickness of the fourth lens element is defined as d7, and the on-axis distance from the image side of the fourth lens to the object side of the fifth lens is defined as d8, satisfying the following relationship: 1 ≤ d7 / d8 ≤ 30. This specifies the ratio of the fourth lens thickness to the air gap between the fourth and fifth lenses. Within this range, the ratio facilitates lens processing and assembly. Preferably, 2 ≤ d7 / d8 ≤ 19 is satisfied. Furthermore, the following relationship is satisfied: 0.01 ≤ d7 / TTL ≤ 0.08. This range facilitates ultra-thin lens fabrication.

[0093] The axial thickness of the fifth lens is defined as d9, which satisfies the following relationship: 0.01≤d9 / TTL≤0.2. When this condition is within the specified range, it is conducive to achieving ultra-thinness. Preferably, 0.056≤d9 / TTL≤0.15 is satisfied.

[0094] Define the focal power of the first lens to be φ1, and the refractive index of the first lens to be nd1; the focal power of the second lens to be φ2, and the refractive index of the second lens to be nd2; the focal power of the third lens to be φ3, and the refractive index of the third lens to be nd3; the focal power of the fourth lens to be φ4, and the refractive index of the fourth lens to be nd4; the focal power of the fifth lens to be φ5, and the refractive index of the fifth lens to be nd5;

[0095] And the following relationship is satisfied:

[0096] φ1= ;

[0097] Φ2= ;

[0098] Φ3= ;

[0099] Φ4= ;

[0100] Φ5= .

[0101] Specifically, the curvature radius of the two surfaces of each lens, the refractive index of the lens, and the lens thickness are selected through the above relationship to calculate its optical focal value, and the relevant parameters of the five lenses are restricted by the range of the above optical focal value, which is conducive to correcting the aberrations of the optical system and achieving an optical effect of having a large imaging range while being as small as possible.

[0102] Preferably, 0.05≤ / mmφ1≤0.1 / mm is satisfied;

[0103] -0.15 / mm≤φ2≤-0.05 / mm;

[0104] -0.15 / mm≤φ3≤-0.1 / mm;

[0105] 0.05 / mm≤φ4≤0.1 / mm;

[0106] 0.05 / mm≤φ5≤0.1 / mm.

[0107] When the focal length of the optical lens 10 of the present invention, the focal length of each lens, the on-axis distance from the image side to the object side of the relevant lens, the on-axis thickness, and the optical focal length satisfy the above-mentioned relationship, the optical lens 10 can have high performance and meet the design requirements of good uniformity, large depth of field, correction of aberrations, and improved imaging quality.

[0108] In this embodiment, the ratio of the total optical length TTL of the optical lens 10 to the image height TTL / IH is less than or equal to 25, which is conducive to achieving ultra-thinness.

[0109] In this embodiment, the aperture F number (Fno) of the optical lens 10 is 4.53, which takes into account both a large depth of field and good imaging performance.

[0110] Such a design can shorten the total optical length TTL of the entire optical lens 10 as much as possible, thereby maintaining the miniaturization characteristic.

[0111] The optical lens 10 of the present invention will be described below using examples. The symbols used in each example are as follows: The focal length, on-axis distance, radius of curvature, and on-axis thickness are in units of mm.

[0112] Tables 1 and 2 show design data of the optical lens 10 according to the first embodiment of the present invention.

[0113]

Table 1

[0114]

[0115] The meanings of the symbols and related nouns are as follows.

[0116] The radius of curvature represents the degree of curvature of the lens surface. A positive value means that the center of the sphere is to the right of the vertex of the sphere, and a negative value means that the center of the sphere is to the left of the vertex of the sphere. "PL" means that the surface is flat and the radius of curvature is infinite. The on-axis thickness represents the axial distance from the center of the current surface to the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A space means that the current position is air and the refractive index is 1.

[0117] S1: object plane;

[0118] R: The curvature radius of the optical surface, or the central curvature radius of the lens;

[0119] R1: the radius of curvature of the object-side surface of the first lens L1;

[0120] R2: the radius of curvature of the image-side surface of the first lens L1;

[0121] R3: radius of curvature of the object-side surface of the second lens L2;

[0122] R4: the radius of curvature of the image-side surface of the second lens L2;

[0123] R5: radius of curvature of the object-side surface of the third lens L3;

[0124] R6: radius of curvature of the image-side surface of the third lens L3;

[0125] R7: radius of curvature of the object-side surface of the fourth lens L4;

[0126] R8: radius of curvature of the image-side surface of the fourth lens L4;

[0127] R9: radius of curvature of the object-side surface of the fifth lens element L5;

[0128] R10: radius of curvature of the image-side surface of the fifth lens L5;

[0129] R11: radius of curvature of the object side of the optical filter GF;

[0130] R12: radius of curvature of the image side of the optical filter GF;

[0131] d: the on-axis thickness of the lens and the on-axis distance between the lenses;

[0132] d0: the on-axis distance from aperture S1 to the object-side surface of the first lens L1;

[0133] d1: axial thickness of the first lens L1;

[0134] d2: the on-axis distance from the image-side surface of the first lens L1 to the object-side surface of the second lens L2;

[0135] d3: axial thickness of the second lens L2;

[0136] d4: the on-axis distance from the image-side surface of the second lens L2 to the object-side surface of the third lens L3;

[0137] d5: axial thickness of the third lens L3;

[0138] d6: the axial distance from the image side surface of the third lens L3 to the aperture stop STO surface;

[0139] d67: the on-axis distance from the aperture STO to the object side of the fourth lens;

[0140] d7: axial thickness of the fourth lens L4;

[0141] d8: the on-axis distance from the image-side surface of the fourth lens L4 to the object-side surface of the fifth lens L5;

[0142] d9: axial thickness of the fifth lens L5;

[0143] d10: the on-axis distance between the image-side surface of the fifth lens L5 and the object-side surface of the optical filter GF;

[0144] d11: axial thickness of the optical filter GF;

[0145] d12: the axial distance from the image side of the optical filter GF to the image plane;

[0146] nd: lens refractive index;

[0147] nd1: refractive index of the first lens L1;

[0148] nd2: the refractive index of the second lens L2;

[0149] nd3: the refractive index of the third lens L3;

[0150] nd4: the refractive index of the fourth lens L4;

[0151] nd5: the refractive index of the fifth lens L5;

[0152] ndg: refractive index of the optical filter GF;

[0153] vd: Abbe number;

[0154] v1: Abbe number of the first lens L1;

[0155] v2: Abbe number of the second lens L2;

[0156] v3: Abbe number of the third lens L3;

[0157] v4: Abbe number of the fourth lens L4;

[0158] v5: Abbe number of the fifth lens L5;

[0159] vg: Abbe number of optical filter GF;

[0160] IH: Like high.

[0161] Figure 3 shows an MTF curve diagram of the optical lens 10 according to the first embodiment; Figure 4 Schematic diagram showing field curvature and distortion of the optical lens 10 according to the first embodiment; Figure 5 A lateral grating diagram of the optical lens 10 according to the first embodiment is shown.

[0162] Table 13 that appears later shows the values ​​corresponding to the various numerical values ​​in Examples 1, 2, and 3 and the parameters specified in the conditional expressions.

[0163] As shown in Table 13, the first embodiment satisfies each conditional expression.

[0164] In this embodiment, the optical lens is suitable for receiving light waves with a wavelength of 450nm to 656nm, the system aperture, i.e., the paraxial working number F / #, is equal to 4.85, the materials used are all environmentally friendly glass materials manufactured by Chengdu Guangming, the effective focal length of the lens is 12.6997 mm, and the distance from the fifth lens to the image plane, i.e., the optical back focus, is 20 mm.

[0165] The optical lens has a paraxial imaging height of 2.105 mm, a paraxial magnification of -0.128, an entrance pupil diameter of 2.803 mm, an exit pupil diameter of 5.225 mm, and a diagonal field of view of 8.8°. The optical lens has good uniformity and a large depth of field, can correct aberrations, improve imaging quality, and has excellent optical characteristics.

[0166] (Second embodiment)

[0167] The second embodiment is substantially the same as the first embodiment, and the meanings of the symbols are the same as those of the first embodiment. Only the differences are listed below.

[0168] Tables 5 and 6 show the design data of the optical lens 20 according to the second embodiment of the present invention.

[0169]

Table 5

[0170]

[0171] Figure 6 shows an MTF curve diagram of the optical lens 20 according to the second embodiment; Figure 7 Schematic diagram showing field curvature and distortion of the optical lens 20 according to the first embodiment; Figure 8 A lateral raster diagram of the optical lens 20 according to the first embodiment is shown.

[0172] As shown in Table 13, the second embodiment satisfies each conditional expression.

[0173] In this embodiment, the optical lens is suitable for receiving light waves with a wavelength of 450nm to 656nm, the system aperture, i.e., the paraxial working number F / #, is equal to 4.85, the materials used are all environmentally friendly glass materials manufactured by Chengdu Guangming, the effective focal length of the lens is 12.7299 mm, and the distance from the fifth lens to the image plane, i.e., the optical back focus, is 20 mm.

[0174] The optical lens has a paraxial imaging height of 2.105 mm, a paraxial magnification of -0.128, an entrance pupil diameter of 2.803 mm, an exit pupil diameter of 5.398 mm, and a diagonal field of view of 8.8°. The optical lens has good uniformity and a large depth of field, can correct aberrations, improve imaging quality, and has excellent optical characteristics.

[0175] (Third embodiment)

[0176] The third embodiment is substantially the same as the first embodiment, and the meanings of the symbols are the same as those of the first embodiment. Only the differences are listed below.

[0177] Tables 9 and 10 show the design data of the optical lens 30 according to the third embodiment of the present invention.

[0178]

Table 9

[0179]

[0180] Figure 9 shows an MTF curve diagram of the optical lens 30 according to the second embodiment; Figure 10 Schematic diagram showing field curvature and distortion of the optical lens 30 according to the third embodiment; Figure 11 A lateral raster diagram of the optical lens 30 according to the third embodiment is shown.

[0181] As shown in Table 13, the third embodiment satisfies each conditional expression.

[0182] In this embodiment, the optical lens is suitable for receiving light waves with a wavelength of 450nm to 656nm, the system aperture, i.e., the paraxial working number F / #, is equal to 4.84, the materials used are all environmentally friendly glass materials manufactured by Chengdu Guangming, the effective focal length of the lens is 12.6568 mm, and the distance from the fifth lens to the image plane, i.e., the optical back focus, is 20 mm.

[0183] The optical lens has a paraxial imaging height of 2.105 mm, a paraxial magnification of -0.128, an entrance pupil diameter of 2.805 mm, an exit pupil diameter of 4.949 mm, and a diagonal field of view of 8.8°. The optical lens has good uniformity and a large depth of field, can correct aberrations, improve imaging quality, and has excellent optical characteristics.

[0184]

Table 13

[0185]

[0186] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present invention, and that in actual applications, various changes may be made in form and detail without departing from the spirit and scope of the present invention.

Claims

1. An optical lens, characterized in that: The optical lens is composed of five lenses, which are as follows from the object side to the image side along the optical axis: The first lens has positive refractive power, its object-side surface is convex and its image-side surface is concave; a second lens having negative optical power, the object-side surface of which is convex and the image-side surface of which is concave; a third lens element having negative optical power, with a concave object-side surface and a concave image-side surface; Aperture; a fourth lens element having positive optical power, whose object-side surface is concave and whose image-side surface is convex; and a fifth lens having positive refractive power, the object-side surface of which is convex and the image-side surface of which is convex; The focal length of the optical lens is defined as f, the focal length of the fifth lens element is defined as f5, the radius of curvature of the object side surface of the fifth lens element is defined as R9, the radius of curvature of the image side surface of the fifth lens element is defined as R10, the axial thickness of the fifth lens element is defined as d9, and the total optical length of the optical lens element is defined as TTL. The optical lens element satisfies the following relationship: 0.1≤f5 / f≤2; 0.2≤(R9+R10) / (R9-R10)≤1.2; 0.01≤d9 / TTL≤0.2; The optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, the optical power of the fourth lens is φ4, and the optical power of the fifth lens is φ5; The optical lens satisfies the following relationship: 0.05 / mm≤φ1≤0.1 / mm; -0.15 / mm≤φ2≤-0.05 / mm; -0.15 / mm≤φ3≤-0.1 / mm; 0.05 / mm≤φ4≤0.1 / mm; 0.05 / mm≤φ5≤0.1 / mm.

2. The optical lens according to claim 1, wherein: The refractive index of the first lens is nd1, the curvature radius of the object side surface of the first lens is R1, the curvature radius of the image side surface of the first lens is R2, and the axial thickness of the first lens is d1; The refractive index of the second lens is nd2, the radius of curvature of the object side surface of the second lens is R3, the radius of curvature of the image side surface of the second lens is R4, and the axial thickness of the second lens is d3; The refractive index of the third lens is nd3, the curvature radius of the object side of the third lens is R5, the curvature radius of the image side of the third lens is R6, and the axial thickness of the third lens is d5; The refractive index of the fourth lens is nd4, the curvature radius of the object side surface of the fourth lens is R7, the curvature radius of the image side surface of the fourth lens is R8, and the axial thickness of the fourth lens is d7; The refractive index of the fifth lens is nd5, the curvature radius of the object side surface of the fifth lens is R9, the curvature radius of the image side surface of the fifth lens is R10, and the axial thickness of the fifth lens is d9; And the following relationship is satisfied: φ1= ; Φ2= ; Φ3= ; Φ4= ; Φ5= 。 3. The optical lens according to claim 1, wherein: The focal length of the first lens is f1, the focal length of the second lens is f2, the axial thickness of the fourth lens is d7, and the axial distance from the image side surface of the fourth lens to the object side surface of the fifth lens is d8, and the following relationship is satisfied: 0.6≤f1 / f≤1.7; -30mm≤f2≤0mm; 1≤d7 / d8≤30.

4. The optical lens according to claim 3, wherein: The optical lens satisfies the following relationship: 0.9≤f1 / f≤1.55; -15mm≤f2≤0mm; 2≤d7 / d8≤19.

5. The optical lens according to claim 2, wherein: The focal length of the second lens is f2; the optical lens satisfies the following relationship: -1.8≤f2 / f≤0; 0.5≤(R3+R4) / (R3-R4)≤4; 0.005≤d3 / TTL≤0.

08.

6. The optical lens according to claim 2, wherein: The focal length of the third lens is f3; the optical lens satisfies the following relationship: -1.2≤f3 / f≤0.7; -1.5≤(R5+R6) / (R5-R6)≤0.85; 0.01≤d5 / TTL≤0.

05.

7. The optical lens according to claim 2, wherein: The focal length of the fourth lens is f4, and the optical lens satisfies the following relationship: 0.1≤f4 / f≤2; 0.5≤(R7+R8) / (R7-R8)≤2.25; 0.01≤d7 / TTL≤0.

08.

8. The optical lens according to claim 1, wherein: The optical lens satisfies the following relationship: 0.1≤(R9+R10) / (R9-R10)≤0.

95.

9. The optical lens according to claim 1, wherein: The axial thickness of the first lens is d1, and the optical lens satisfies the following relationship: 0.01≤d1 / TTL≤0.08.

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