Range finder and imaging lens thereof

Abstract

A rangefinder and an imaging lens thereof, wherein the imaging lens comprises first, second, third, fourth, fifth, sixth, seventh, eighth and ninth lenses. The first lens is a meniscus lens with negative power and comprises a convex surface facing the object side and a concave surface facing the image side. The second lens is a meniscus lens with positive power. The third lens is a double convex lens with positive power. The fourth lens has positive power. The fifth lens and the eighth lens have negative power. The sixth lens is a meniscus lens with power. The seventh lens has power and comprises a concave surface facing the image side. The ninth lens has power and comprises a convex surface facing the image side. The first, second, third, fourth, fifth, sixth, seventh, eighth and ninth lenses are arranged in order from the object side to the image side along the optical axis.

Description

Technical Field

[0001] This invention relates to a rangefinder and its imaging lens. Background Technology

[0002] The current development trend of long focal length imaging lenses used in rangefinders, in addition to increasing focal length, also requires miniaturization and high resolution capabilities to meet different application needs. Existing imaging lenses can no longer meet current needs, and a new imaging lens architecture is needed to simultaneously meet the requirements of long focal length, miniaturization and high resolution. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the shortcomings of existing imaging lenses in that they cannot simultaneously meet the requirements of long focal length, miniaturization and high resolution, and to provide a rangefinder and its imaging lens, wherein the imaging lens has a long focal length, a short total lens length and a high resolution, but still has good optical performance.

[0004] The technical solution adopted by the present invention to solve its technical problem is to provide an imaging lens comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens. The first lens is a meniscus lens with negative refractive power and includes a convex surface facing the object side and a concave surface facing the image side. The second lens has positive refractive power and is also a meniscus lens. The third lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing the image side. The fourth lens has positive refractive power. The fifth lens has negative refractive power. The sixth lens is a meniscus lens with refractive power. The seventh lens has refractive power and includes a concave surface facing the image side. The eighth lens has negative refractive power. The ninth lens has refractive power and includes a convex surface facing the image side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are arranged sequentially along the optical axis from the object side to the image side.

[0005] The fourth lens is a biconvex lens, and includes a convex surface facing the object side and another convex surface facing the image side; the fifth lens is a biconcave lens, and includes a concave surface facing the object side and another concave surface facing the image side; the sixth lens has positive refractive power; the seventh lens has negative refractive power; the ninth lens has positive refractive power; and the eighth lens is a biconcave lens, and includes a concave surface facing the object side and another concave surface facing the image side.

[0006] wherein the second lens includes a convex surface facing the object side and a concave surface facing the image side; the sixth lens includes a convex surface facing the object side and a concave surface facing the image side; and the ninth lens is a biconvex lens and may further include another convex surface facing the object side.

[0007] wherein the seventh lens is a biconcave lens and may further include another concave surface facing the object side.

[0008] wherein the seventh lens is a plano-concave lens and may further include a flat surface facing the object side.

[0009] wherein the seventh lens is movable in a direction perpendicular to the optical axis to perform optical image stabilization.

[0010] wherein the first lens and the second lens are cemented.

[0011] wherein the imaging lens satisfies at least one of the following conditions: 0.85<TTL / f<0.9; 1.23<|f / f7|<1.30; 0.71<TTL / f6<0.86; 3.0<|f89 / f7|<4.1; Vd3>60; 7<TTL / BFL<11; 0.5<R11 / TTL<0.9; 0.1<|R92 / TTL|<0.5; 4<R11 / BFL<8; 1<|R92 / BFL|<4; wherein TTL is the distance on the optical axis from the object side surface of the first lens to the imaging plane, BFL is the distance on the optical axis from the image side surface of the ninth lens to the imaging plane, f is the effective focal length of the imaging lens, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, f89 is the combined effective focal length of the eighth lens and the ninth lens, R11 is the radius of curvature of the object side surface of the first lens, R92 is the radius of curvature of the image side surface of the ninth lens, and Vd3 is the Abbe number of the third lens.

[0012] The present invention provides a range finder comprising a transmitting module; a receiving module; an objective lens; an imaging lens; and a display module; wherein the transmitting module emits a light beam toward a measured object; wherein the measured object reflects the light beam, causing the light beam to pass through the objective lens toward the receiving module; wherein the imaging lens captures an image of the measured object; wherein the display module displays the image of the measured object.

[0013] The range finder of the present invention may further comprise an eyepiece module disposed adjacent to the display module, so that the display module can be viewed through the eyepiece module.

[0014] By implementing the range finder and the imaging lens thereof of the present invention, the imaging lens has a longer focal length, a shorter total lens length, higher resolution, and still maintains good optical performance. Brief Description of the Drawings

[0015] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the lens configuration according to a first embodiment of the imaging lens of the present invention.

[0017] Figure 2A , 2B 2C, 2D, and 2E are respectively the longitudinal aberration diagram, field curvature diagram, distortion diagram, lateral chromatic aberration diagram, and modulation transfer function diagram of the first embodiment of the imaging lens according to the present invention.

[0018] Figure 3 This is a schematic diagram of the lens configuration according to a second embodiment of the imaging lens of the present invention.

[0019] Figure 4A , 4B 4C, 4D, and 4E are respectively the longitudinal aberration diagram, field curvature diagram, distortion diagram, lateral chromatic aberration diagram, and modulation conversion function diagram of the second embodiment of the imaging lens according to the present invention.

[0020] Figure 5 This is a schematic diagram of the lens configuration according to a third embodiment of the imaging lens of the present invention.

[0021] Figure 6A , 6B 6C, 6D, and 6E are respectively the longitudinal aberration diagram, field curvature diagram, distortion diagram, lateral chromatic aberration diagram, and modulation conversion function diagram of the imaging lens according to the third embodiment of the present invention.

[0022] Figure 7 This is a schematic diagram of the lens configuration according to the fourth embodiment of the imaging lens of the present invention.

[0023] Figure 8A , 8B 8C, 8D, and 8E are respectively the longitudinal aberration diagram, field curvature diagram, distortion diagram, lateral chromatic aberration diagram, and modulation conversion function diagram of the imaging lens according to the fourth embodiment of the present invention. Detailed Implementation

[0024] The present invention provides an imaging lens, comprising: a first lens having negative refractive power, the first lens being a meniscus lens and including a convex surface facing the object side and a concave surface facing the image side; a second lens having positive refractive power, the second lens being a meniscus lens; a third lens having positive refractive power, the third lens being a biconvex lens and including a convex surface facing the object side and another convex surface facing the image side; a fourth lens having positive refractive power; a fifth lens having negative refractive power; a sixth lens having positive refractive power, the sixth lens being a meniscus lens; a seventh lens having negative refractive power, the seventh lens including a concave surface facing the image side; an eighth lens having negative refractive power; and a ninth lens having positive refractive power, the ninth lens including a convex surface facing the image side; wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are arranged sequentially along the optical axis from the object side to the image side.

[0025] Please refer to Tables 1, 2, 4, 5, 7, 8, 10 and 11 below. Tables 1, 4, 7 and 10 are the relevant parameter tables for each lens in the first to fourth embodiments of the imaging lens according to the present invention. Tables 2, 5, 8 and 11 are the relevant parameter tables for the aspherical surface of the aspherical lens in Tables 1, 4, 7 and 10.

[0026] Figure 1 , 3 Figures 5, 6, and 7 are schematic diagrams of lens configurations in the first, second, third, and fourth embodiments of the imaging lens of the present invention, respectively. Among them, the first lenses L11, L21, L31, and L41 are meniscus lenses with negative refractive power, made of glass, with their object-side surfaces S11, S21, S31, and S41 being convex surfaces and their image-side surfaces S12, S22, S32, and S42 being concave surfaces. The object-side surfaces S11, S21, S31, and S41 and the image-side surfaces S12, S22, S32, and S42 are all spherical surfaces.

[0027] The second lenses L12, L22, L32, and L42 are meniscus lenses with positive refractive power. They are made of glass, with the object-side surfaces S12, S22, S32, and S42 being convex and the image-side surfaces S13, S23, S33, and S43 being concave. Both the object-side surfaces S12, S22, S32, and S42 and the image-side surfaces S13, S23, S33, and S43 are spherical surfaces.

[0028] The first lenses L11, L21, L31, and L41 are cemented together with the second lenses L12, L22, L32, and L42.

[0029] The third lenses L13, L23, L33, and L43 are biconvex lenses with positive refractive power. They are made of glass, and their object-side surfaces S14, S24, S34, and S44 are convex, as are their image-side surfaces S15, S25, S35, and S45. Both the object-side surfaces S14, S24, S34, and S44 and the image-side surfaces S15, S25, S35, and S45 are spherical surfaces.

[0030] The fourth lenses L14, L24, L34, and L44 are biconvex lenses with positive refractive power. They are made of glass, with the object-side surfaces S16, S26, S36, and S46 being convex surfaces, and the image-side surfaces S17, S27, S37, and S47 being convex surfaces. The object-side surfaces S16, S26, S36, and S46, as well as the image-side surfaces S17, S27, S37, and S47, are all spherical surfaces.

[0031] The fifth lenses L15, L25, L35, and L45 are biconcave lenses with negative refractive power, made of glass. Their object-side surfaces S18, S28, S38, and S48 are concave, and their image-side surfaces S19, S29, S39, and S49 are concave. Both the object-side surfaces S18, S28, S38, and S48 and the image-side surfaces S19, S29, S39, and S49 are spherical surfaces.

[0032] The sixth lenses L16, L26, L36, and L46 are meniscus lenses with positive refractive power. They are made of glass, with the object side S110, S210, S310, and S410 being convex surfaces, and the image side S111, S211, S311, and S411 being concave surfaces.

[0033] The seventh lenses L17, L27, L37, and L47 have negative refractive power and are made of glass. Their image sides S113, S213, S313, and S413 are concave and aspherical.

[0034] The eighth lenses L18, L28, L38, and L48 are biconcave lenses with negative refractive power. They are made of glass, with their object sides S114, S214, S314, and S414 being concave, and their image sides S115, S215, S315, and S415 being concave.

[0035] The ninth lenses L19, L29, L39, and L49 are biconvex lenses with positive refractive power, made of glass. Their object-side surfaces S116, S216, S316, and S416 are convex, and their image-side surfaces S117, S217, S317, and S417 are convex. Both the object-side surfaces S116, S216, S316, and S416 and the image-side surfaces S117, S217, S317, and S417 are aspherical surfaces.

[0036] In addition, the imaging lenses 1, 2, 3, 4 satisfy at least one of the following condition (1) to condition (10):

[0037]

[0038] Herein, TTL is the distance on the optical axes OA1, OA2, OA3, OA4 from the object-side surfaces S11, S21, S31, S41 of the first lenses L11, L21, L31, L41 to the imaging planes IMA1, IMA2, IMA3, IMA4 in the first to fourth embodiments, BFL is the distance on the optical axes OA1, OA2, OA3, OA4 from the image-side surfaces S117, S217, S317, S417 of the ninth lenses L19, L29, L39, L49 to the imaging planes IMA1, IMA2, IMA3, IMA4 in the first to fourth embodiments, f is the effective focal length of the imaging lenses 1, 2, 3, 4 in the first to fourth embodiments, f6 is the effective focal length of the sixth lenses L16, L26, L36, L46 in the first to fourth embodiments, f7 is the effective focal length of the seventh lenses L17, L27, L37, L47 in the first to fourth embodiments, f89 is the combined effective focal length of the eighth lenses L18, L28, L38, L48 and the ninth lenses L19, L29, L39, L49 in the first to fourth embodiments, R11 is the radius of curvature of the object-side surfaces S11, S21, S31, S41 of the first lenses L11, L21, L31, L41 in the first to fourth embodiments, R92 is the radius of curvature of the image-side surfaces S117, S217, S317, S417 of the ninth lenses L19, L29, L39, L49 in the first to fourth embodiments, and Vd3 is the Abbe number of the third lenses L13, L23, L33, L43 in the first to fourth embodiments. This enables the imaging lenses 1, 2, 3, 4 to effectively shorten the total lens length, effectively improve resolution, effectively correct aberrations, and effectively correct chromatic aberration.

[0039] When condition (1): 0.85<TTL / f<0.9 is satisfied, the total lens length can be effectively shortened; when condition (2): 1.23<|f / f7|<1.30 is satisfied, optical image stabilization can be effectively achieved; when condition (3): 0.71<TTL / f6<0.86 is satisfied, the resolution can be effectively improved.

[0040] The first embodiment of the imaging lens of the present invention will now be described in detail. The imaging lens 1, along the optical axis OA1 from the object side to the image side, sequentially includes a first lens L11, a second lens L12, a third lens L13, a fourth lens L14, a fifth lens L15, a sixth lens L16, a seventh lens L17, an eighth lens L18, a ninth lens L19, and a filter OF1. During imaging, the light rays from the object side are finally imaged onto the imaging plane IMA1. According to paragraphs 1 to 12 of the [Specific Implementation], the object-side surface S110 and image-side surface S111 of the sixth lens L16 are both spherical surfaces; the seventh lens L17 is a biconcave lens, with its object-side surface S112 being concave and its object-side surface S112 being an aspherical surface; the object-side surface S114 and image-side surface S115 of the eighth lens L18 are both aspherical surfaces; the object-side surface S118 and image-side surface S119 of the filter OF1 are both planar; by utilizing the above-mentioned lenses and the design that satisfies at least one of conditions (1) to (10), the imaging lens 1 can effectively shorten the total length of the lens, effectively improve the resolution, effectively correct aberrations, and effectively correct chromatic aberrations.

[0041] Table 1 shows the relevant parameters of each lens in imaging lens 1.

[0042] Table 1

[0043]

[0044]

[0045] The aspherical surface concavity z of the aspherical lens in Table 1 is obtained by the following formula: z = ch 2 / {1+[1-(k+1)c 2 h 2 ] 1 / 2}+Ah 4 +Bh 6 +Ch 8 ;

[0046] Where: c: curvature; h: perpendicular distance from any point on the lens surface to the optical axis; k: conic coefficient; A~C: aspherical coefficient.

[0047] Table 2 is a table of relevant parameters for the aspherical surface of the aspherical lens in Table 1, where k is the conic constant and A to C are the aspherical coefficients.

[0048] Table 2

[0049]

[0050] Table 3 shows the relevant parameter values ​​of the imaging lens 1 in the first embodiment and the calculated values ​​of the corresponding conditions (1) to (10). As can be seen from Table 3, the imaging lens 1 in the first embodiment can meet the requirements of conditions (1) to (10).

[0051] Table 3

[0052]

[0053]

[0054] Furthermore, the optical performance of the imaging lens 1 in the first embodiment also meets the requirements. Figures 2A-2E As can be seen, the imaging lens 1 of the first embodiment has a longitudinal aberration between -0.01mm and 0.04mm, a field curvature between -0.01mm and 0.03mm, a distortion between 0% and 0.8%, a lateral chromatic aberration between -1.5μm and 0.5μm, and a modulation transfer function value between 0.35 and 1.0. Clearly, the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 1 of the first embodiment can be effectively corrected, and the lens resolution can meet the requirements, thus achieving better optical performance.

[0055] The second embodiment of the imaging lens of the present invention will now be described in detail. Please refer to... Figure 3 The imaging lens 2, along the optical axis OA2 from the object side to the image side, includes, in sequence, a first lens L21, a second lens L22, a third lens L23, a fourth lens L24, a fifth lens L25, a sixth lens L26, a seventh lens L27, an eighth lens L28, a ninth lens L29, and a filter OF2. During imaging, the light rays from the object side are finally imaged onto the imaging plane IMA2. According to paragraphs 1 to 12 of the [Specific Implementation], the object-side surface S210 and image-side surface S211 of the sixth lens L26 are both aspherical surfaces; the seventh lens L27 is a biconcave lens, with its object-side surface S212 being concave and its object-side surface S212 being aspherical; the object-side surface S214 and image-side surface S215 of the eighth lens L28 are both spherical surfaces; the object-side surface S218 and image-side surface S219 of the filter OF2 are both planar; by utilizing the above lenses and the design that satisfies at least one of conditions (1) to (10), the imaging lens 2 can effectively shorten the total length of the lens, effectively improve the resolution, effectively correct aberrations, and effectively correct chromatic aberrations.

[0056] Table 4 shows the relevant parameters of each lens in imaging lens 2.

[0057] Table 4

[0058]

[0059]

[0060] The definition of the aspherical surface concavity z of the aspherical lens in Table 4 is the same as the definition of the aspherical surface concavity z of the aspherical lens in Table 1 of the first embodiment, and will not be repeated here.

[0061] Table 5 is a table of relevant parameters for the aspherical surface of the aspherical lens in Table 4, where k is the conic constant and A to C are the aspherical coefficients.

[0062] Table 5

[0063]

[0064] Table 6 shows the relevant parameter values ​​of the imaging lens 2 in the second embodiment and the calculated values ​​of the corresponding conditions (1) to (10). As can be seen from Table 6, the imaging lens 2 in the second embodiment can meet the requirements of conditions (1) to (10).

[0065] Table 6

[0066] R92 -11.73mm TTL / f 0.90 |f / f7| 1.24 TTL / f6 0.85 |f89 / f7| 3.05 Vd3 81.61 TTL / BFL 9.29 R11 / TTL 0.72 |R92 / TTL| 0.30 R11 / BFL 6.68 |R92 / BFL| 2.79

[0067] Furthermore, the optical performance of the imaging lens 2 in the second embodiment also meets the requirements. Figures 4A-4E As can be seen, the imaging lens 2 of the second embodiment has a longitudinal aberration between -0.01mm and 0.05mm, a field curvature between -0.02mm and 0.06mm, a distortion between 0% and 0.8%, a lateral chromatic aberration between -2.5μm and 0.5μm, and a modulation transfer function value between 0.28 and 1.0. Clearly, the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 2 of the second embodiment can be effectively corrected, and the lens resolution can meet the requirements, thus achieving better optical performance.

[0068] The third embodiment of the imaging lens of the present invention will now be described in detail. Please refer to... Figure 5The imaging lens 3, along the optical axis OA3 from the object side to the image side, includes, in sequence, a first lens L31, a second lens L32, a third lens L33, a fourth lens L34, a fifth lens L35, a sixth lens L36, a seventh lens L37, an eighth lens L38, a ninth lens L39, and a filter OF3. During imaging, the light rays from the object side are finally imaged onto the imaging plane IMA3. According to paragraphs 1 to 12 of the [Specific Implementation], the object-side surface S310 and image-side surface S311 of the sixth lens L36 are both aspherical surfaces; the seventh lens L37 is a plano-concave lens, and its object-side surface S312 is a plane; the object-side surface S314 and image-side surface S315 of the eighth lens L38 are both spherical surfaces; the object-side surface S318 and image-side surface S319 of the filter OF3 are both planes; by using the above lenses and the design that satisfies at least one of conditions (1) to (10), the imaging lens 3 can effectively shorten the total length of the lens, effectively improve the resolution, effectively correct aberrations, and effectively correct chromatic aberrations.

[0069] Table 7 shows the relevant parameters of each lens in imaging lens 3.

[0070] Table 7

[0071]

[0072]

[0073] The definition of the aspherical surface concavity z of the aspherical lens in Table 7 is the same as the definition of the aspherical surface concavity z of the aspherical lens in Table 1 of the first embodiment, and will not be repeated here.

[0074] Table 8 is a table of relevant parameters for the aspherical surface of the aspherical lens in Table 7, where k is the conic constant and A to C are the aspherical coefficients.

[0075] Table 8

[0076]

[0077] Table 9 shows the relevant parameter values ​​of the imaging lens 3 in the third embodiment and the calculated values ​​of the corresponding conditions (1) to (10). As can be seen from Table 9, the imaging lens 3 in the third embodiment can meet the requirements of conditions (1) to (10).

[0078] Table 9

[0079] R92 -13.93mm TTL / f 0.90 |f / f7| 1.24 TTL / f6 0.83 |f89 / f7| 3.27 Vd3 81.61 TTL / BFL 9.30 R11 / TTL 0.72 |R92 / TTL| 0.28 R11 / BFL 6.68 |R92 / BFL| 2.63

[0080] Furthermore, the optical performance of the imaging lens 3 in the third embodiment also meets the requirements. Figures 6A-6EAs can be seen, the imaging lens 3 of the third embodiment has a longitudinal aberration between -0.01mm and 0.06mm, a field curvature between -0.05mm and 0.06mm, a distortion between 0% and 0.9%, a lateral chromatic aberration between -3.5μm and 0.5μm, and a modulation transfer function value between 0.22 and 1.0. Clearly, the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 3 of the third embodiment can be effectively corrected, and the lens resolution can meet the requirements, thus achieving better optical performance.

[0081] The fourth embodiment of the imaging lens of the present invention will now be described in detail. Referring to Figure 7, the imaging lens 4 includes, along the optical axis OA4 from the object side to the image side, a first lens L41, a second lens L42, a third lens L43, a fourth lens L44, a fifth lens L45, a sixth lens L46, a seventh lens L47, an eighth lens L48, a ninth lens L49, and a filter OF4. During imaging, the light rays from the object side are finally imaged onto the imaging surface IMA4. According to paragraphs 1 to 12 of the [Specific Implementation], the object-side surface S410 and image-side surface S411 of the sixth lens L46 are both aspherical surfaces; the seventh lens L47 is a plano-concave lens, and its object-side surface S412 is a plane; the object-side surface S414 and image-side surface S415 of the eighth lens L48 are both spherical surfaces; the object-side surface S418 and image-side surface S419 of the filter OF4 are both planes; by using the above lenses and the design that satisfies at least one of conditions (1) to (10), the imaging lens 4 can effectively shorten the total length of the lens, effectively improve the resolution, effectively correct aberrations, and effectively correct chromatic aberrations.

[0082] Table 10 shows the relevant parameters of each lens in imaging lens 4.

[0083] Table 10

[0084]

[0085] The definition of the aspherical surface concavity z of the aspherical lens in Table 10 is the same as the definition of the aspherical surface concavity z of the aspherical lens in Table 1 of the first embodiment, and will not be repeated here.

[0086] Table 11 is a table of relevant parameters for the aspherical surface of the aspherical lens in Table 10, where k is the conic constant and A to C are the aspherical coefficients.

[0087] Table 11

[0088]

[0089] Table 12 shows the relevant parameter values ​​of the imaging lens 4 in the fourth embodiment and the calculated values ​​of the corresponding conditions (1) to (10). As can be seen from Table 12, the imaging lens 4 in the fourth embodiment can meet the requirements of conditions (1) to (10).

[0090] Table 12

[0091] R92 -8.5mm TTL / f 0.87 |f / f7| 1.28 TTL / f6 0.72 |f89 / f7| 3.16 Vd3 81.61 TTL / BFL 9.35 R11 / TTL 0.73 |R92 / TTL| 0.22 R11 / BFL 6.85 |R92 / BFL| 2.04

[0092] Furthermore, the optical performance of the imaging lens 4 in the fourth embodiment also meets the requirements. Figures 8A-8E As can be seen, the imaging lens 4 of the fourth embodiment has a longitudinal aberration between -0.02mm and 0.09mm, a field curvature between -0.08mm and 0.05mm, a distortion between -0.1% and 0.6%, a lateral chromatic aberration between -2.5μm and 0.5μm, and a modulation transfer function value between 0.26 and 1.0. Clearly, the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 4 of the fourth embodiment can be effectively corrected, and the lens resolution can meet the requirements, thus achieving better optical performance.

[0093] The following describes one embodiment of the rangefinder of the present invention, but the illustrations are omitted. The rangefinder includes a transmitting module, a receiving module, an objective lens, an imaging lens, and a display module. The transmitting module emits a light beam toward the object being measured. The object reflects the incident light beam, causing the beam to strike the objective lens. After passing through the objective lens, the beam strikes the receiving module. The receiving module receives the beam and calculates the distance to the object, which is then displayed on the display module for visual viewing. The imaging lens is used to capture an image of the object being measured, which is also displayed on the display module for visual viewing. The imaging lens can be imaging lenses 1, 2, 3, and 4 of the first, second, third, and fourth embodiments. The objective lens is used to collect the light beam reflected by the object being measured, ensuring that the receiving module receives the maximum energy of the beam after it passes through the objective lens. The objective lens does not capture an image of the object being measured; that is, the objective lens is not responsible for imaging the object. The function of the imaging lens is to capture the image of the object under test. In other words, the light beam reflected by the object under test will not pass through the imaging lens and then be introduced into the receiving module.

[0094] The above-described rangefinder embodiment may further include an eyepiece module, which is located next to the display module so that the user can view the display module through the eyepiece module.

[0095] In the above-described embodiment of the rangefinder, the display module can be removed and an eyepiece module can be added. The eyepiece module is positioned between the imaging surface of the imaging lens and an image sensor, allowing the user to visually view the object being measured through the eyepiece module and the imaging lens.

[0096] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. An imaging lens, characterized in that, include: The first lens has negative refractive power. The first lens is a meniscus lens and includes a convex surface facing the object side and a concave surface facing the image side. The second lens has positive refractive power and is a meniscus lens. The third lens has positive refractive power. The third lens is a biconvex lens and includes a convex surface facing the object side and another convex surface facing the image side. The fourth lens has positive refractive power; The fifth lens has negative refractive power; The sixth lens has positive refractive power; this sixth lens is a meniscus lens. The seventh lens has negative refractive power and includes a concave surface facing the image side; The eighth lens has negative refractive power; and The ninth lens has positive refractive power and includes a convex surface facing the image side; The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are arranged sequentially along the optical axis from the object side to the image side.

2. The imaging lens as described in claim 1, characterized in that: The fourth lens is a biconvex lens, and includes one convex surface facing the object side and another convex surface facing the image side; The fifth lens is a biconcave lens, and includes one concave surface facing the object side and another concave surface facing the image side; as well as The eighth lens is a biconcave lens, and includes one concave surface facing the object side and another concave surface facing the image side.

3. The imaging lens as described in claim 2, characterized in that... : The second lens includes a convex surface facing the object side and a concave surface facing the image side; The sixth lens includes a convex surface facing the object side and a concave surface facing the image side; and The ninth lens is a biconvex lens and further includes another convex surface facing the object side.

4. The imaging lens as described in claim 3, characterized in that, The seventh lens is a biconcave lens and further includes another concave surface facing the object side.

5. The imaging lens as described in claim 3, characterized in that, The seventh lens is a plano-concave lens and further includes a plane facing the object side.

6. The imaging lens as described in any one of claims 1 to 5, characterized in that, The seventh lens can be moved along a direction perpendicular to the optical axis to provide optical shatter protection.

7. The imaging lens as described in any one of claims 1 to 5, characterized in that, The first lens and the second lens are cemented together.

8. The imaging lens as described in any one of claims 1 to 5, characterized in that, The imaging lens satisfies at least one of the following conditions: 0.85 < TTL / f < 0.9; 1.23 < |f / f7 | < 1.30; 0.71 < TTL / f6 < 0.86; 3.0 < |f89 / f7 | < 4.1; Vd3 > 60; 7 < TTL / BFL < 11; 0.5 < R11 / TTL < 0.9; 0.1 < |R92 / TTL| < 0.5; 4 < R11 / BFL < 8; 1 < |R92 / BFL | < 4; Wherein, TTL is the distance from the object side of the first lens to the imaging plane on the optical axis, BFL is the distance from the image side of the ninth lens to the imaging plane on the optical axis, f is the effective focal length of the imaging lens, f6 is the effective focal length of the sixth lens, f7 is the effective focal length of the seventh lens, f89 is the combined effective focal length of the eighth and ninth lenses, R11 is the radius of curvature of the object side of the first lens, R92 is the radius of curvature of the image side of the ninth lens, and Vd3 is the Abbe coefficient of the third lens.

9. A rangefinder, characterized in that, include: Transmission module; Receiver module; Objective lens; Imaging lens as described in any one of claims 1 to 8; as well as Display module; The transmitting module emits a beam of light toward a target object; The object under test reflects the light beam, causing it to pass through the objective lens and be directed towards the receiving module. The imaging lens captures the image of the object being measured. The display module shows the image of the object being measured.

10. The rangefinder as described in claim 9, characterized in that, It also includes an eyepiece module, which is located next to the display module so that the display module can be viewed through the eyepiece module.

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