Focusing liquid double telecentric lens and intelligent production equipment

Abstract

The invention provides a focus-adjustable liquid double telecentric lens and intelligent production equipment, and relates to the technical field of optical lenses. The focus-adjustable liquid double telecentric lens comprises a first lens, a second lens, a third lens, a liquid lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object space to an image space along an optical axis; the first lens is a biconvex lens with positive focal power, 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 biconcave lens with negative focal power, the fifth lens is a biconvex lens with positive focal power, and the sixth lens is a biconvex lens with positive focal power. Wherein the focusing position of the focusable liquid double telecentric lens is changed by adjusting the driving voltage or the driving current of the liquid lens, and rapid focusing under different working distances is completed. According to the embodiment of the invention, the system is small in size, and is excellent in imaging quality in a large depth-of-field range.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a focus-adjustable liquid bi-telecentric lens and intelligent production equipment. Background Art

[0002] Telecentric lenses are currently commonly used in the field of machine vision automated inspection. Ordinary industrial lenses will cause fluctuations in magnification when the working distance changes, which in turn affects the accuracy of the measurement results. The original intention of the design of telecentric lenses is to correct the parallax problem of traditional industrial lenses. It can keep the image magnification constant within a certain working distance range, and will not affect the measurement accuracy due to the height change of the object position, thereby achieving high-precision detection of objects.

[0003] However, the existing adjustable focus telecentric lens has a relatively small depth of field, which means that it can only produce clear images within a small working distance range. In addition, telecentric lenses generally have a larger number of lenses under the same working distance and resolution requirements, which makes the telecentric lens relatively large in size, occupies more space, and therefore has a relatively high cost. Summary of the invention

[0004] The embodiment of the present invention provides a focus-adjustable liquid bi-telecentric lens and intelligent production equipment to achieve small size and excellent imaging quality within a large depth of field.

[0005] In a first aspect, an embodiment of the present invention provides a focus-adjustable liquid bi-telecentric lens, comprising a first lens, a second lens, a third lens, a liquid lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence from the object side to the image side along an optical axis;

[0006] The first lens is a biconvex lens with positive optical power, the second lens is a biconvex lens with positive optical power, the third lens is a biconcave lens with negative optical power, the fourth lens is a biconcave lens with negative optical power, the fifth lens is a biconvex lens with positive optical power, and the sixth lens is a biconvex lens with positive optical power;

[0007] The focusing position of the adjustable-focus liquid bi-telecentric lens is changed by adjusting the driving voltage or driving current of the liquid lens, thereby achieving rapid focusing at different working distances.

[0008] Optionally, the second lens and the third lens are cemented to form a cemented lens; and / or, the fourth lens and the fifth lens are cemented to form a cemented lens.

[0009] Optionally, parameters of at least two lenses among the first lens, the second lens, the fifth lens, and the sixth lens are different;

[0010] and / or,

[0011] The third lens is different from the fourth lens.

[0012] Optionally, the optical focal length of the liquid lens is P, satisfying: -5dpt≤P≤5dpt.

[0013] Optionally, the working distance of the adjustable-focus liquid bi-telecentric lens is D, and the magnification of the adjustable-focus liquid bi-telecentric lens is M, satisfying:

[0014] 124mm≤D≤149mm; and / or, 0.497≤M≤0.511.

[0015] Optionally, a diaphragm is further included, and the diaphragm is located between the third lens and the liquid lens.

[0016] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all glass spherical lenses.

[0017] Optionally, the first lens and the second lens are spaced apart, the third lens and the liquid lens are spaced apart, the liquid lens and the fourth lens are spaced apart, and the fifth lens and the sixth lens are spaced apart.

[0018] Optionally, at least one of the following conditions is satisfied between the lenses:

[0019] The optical interval between the first lens and the second lens is between 8 mm ± 1 mm;

[0020] The optical distance between the third lens and the liquid lens is between 49 mm ± 1 mm;

[0021] The optical spacing between the liquid lens and the fourth lens is between 7 mm ± 1 mm;

[0022] An optical interval between the fifth lens and the sixth lens is between 0.2 mm±0.1 mm.

[0023] Optionally, each lens satisfies at least one of the following conditions:

[0024] The radius of curvature of the object side surface of the first lens is 116 mm ± 2 mm, and the radius of curvature of the image side surface of the first lens is -84 mm ± 2 mm;

[0025] The radius of curvature of the object side surface of the second lens is 46 mm ± 2 mm, and the radius of curvature of the image side surface of the second lens is -50 mm ± 2 mm;

[0026] The curvature radius of the object side surface of the third lens is -50 mm ± 2 mm, and the curvature radius of the image side surface of the third lens is 600 mm ± 2 mm;

[0027] The curvature radius of the object side surface of the fourth lens is -9 mm ± 2 mm, and the curvature radius of the image side surface of the fourth lens is 25 mm ± 2 mm;

[0028] The curvature radius of the object side surface of the fifth lens is 25 mm ± 2 mm, and the curvature radius of the image side surface of the fifth lens is -13 mm ± 2 mm;

[0029] The curvature radius of the object side surface of the sixth lens is 39 mm±2 mm, and the curvature radius of the image side surface of the sixth lens is -47 mm±2 mm.

[0030] Optionally, each lens satisfies at least one of the following conditions:

[0031] The refractive index of the first lens is 1.5±0.1, and the Abbe number of the first lens is 81.5±1;

[0032] The refractive index of the second lens is 1.5±0.1, and the Abbe number of the second lens is 81.5±1;

[0033] The refractive index of the third lens is 1.6±0.1, and the Abbe number of the third lens is 35.7±1;

[0034] The refractive index of the fourth lens is 1.6±0.1, and the Abbe number of the fourth lens is 37±1;

[0035] The refractive index of the fifth lens is 1.5±0.1, and the Abbe number of the fifth lens is 56±1;

[0036] The refractive index of the sixth lens is 1.7±0.1, and the Abbe number of the sixth lens is 52.3±1.

[0037] In a second aspect, an embodiment of the present invention provides an intelligent production equipment, comprising the focus-adjustable liquid bi-telecentric lens described in the first aspect.

[0038] The embodiment of the present invention provides a focus-adjustable liquid bi-telecentric lens. By setting the surface shape of the first lens to the sixth lens, the specific arrangement method and the curvature radius, and coordinating the optical focal length setting of the liquid lens in the focus-adjustable liquid bi-telecentric lens, the lens can have excellent imaging quality within a large depth of field while ensuring a small volume. Through the above-mentioned settings, the focus-adjustable liquid bi-telecentric lens provided by the embodiment of the present invention can achieve a large depth of field of 25 mm, which is much higher than that of an ordinary focus-adjustable liquid bi-telecentric lens. In addition, by adjusting the driving voltage or driving current of the liquid lens, the focusing position of the focus-adjustable liquid bi-telecentric lens can be changed to complete rapid focusing at different working distances, thereby further improving the accuracy and efficiency of machine vision detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a principle diagram of the optical path of a focus-adjustable liquid bi-telecentric lens provided in the first embodiment of the present invention;

[0040] Figure 2 is a structural schematic diagram of a focus-adjustable liquid bi-telecentric lens provided in Embodiment 1 of the present invention;

[0041] Figure 3 Field curvature diagram of the focus-adjustable liquid bi-telecentric lens provided in Embodiment 1 of the present invention at a working distance of 149 mm;

[0042] Figure 4 Distortion diagram of the focus-adjustable liquid bi-telecentric lens provided in Example 1 of the present invention at a working distance of 149 mm;

[0043] Figure 5 The optical transfer function diagram of the focus-adjustable liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm;

[0044] Figure 6 Relative illumination diagram of the image plane of the focus-adjustable liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm;

[0045] Figure 7 The spot diagram of the focus-adjustable liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm;

[0046] Figure 8 Field curvature diagram of the focus-adjustable liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm;

[0047] Fig. 9 Distortion diagram of the focus-adjustable liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm;

[0048] Fig.10The optical transfer function diagram of the focus-adjustable liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm;

[0049] Fig.11 Relative illumination diagram of the image plane of the focus-adjustable liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm;

[0050] Fig.12 The point diagram of the focus-adjustable liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm. DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0052] Embodiment 1

[0053] Figure 1 is a schematic diagram of the optical path of a focus-adjustable liquid bi-telecentric lens provided in the first embodiment of the present invention, Figure 2 is a schematic diagram of the structure of the adjustable focus liquid bi-telecentric lens provided in the first embodiment of the present invention, with reference to Figure 1 and Figure 2 The focus-adjustable liquid bi-telecentric lens comprises a first lens 1, a second lens 2, a third lens 3, a liquid lens 8, a fourth lens 4, a fifth lens 5 and a sixth lens 6 which are arranged in sequence from the object side to the image side along the optical axis. The above lenses all have an object side surface facing the object side (i.e., the object side, the object plane OBJ) and an image side surface facing the image side (i.e., the image side, the image plane IMG). The above lenses are coaxially arranged, and the common axis of the lenses is the optical axis of the focus-adjustable liquid bi-telecentric lens.

[0054] The first lens 1 is a biconvex lens with positive power. The first lens 1 has positive power. The object side surface R11 of the first lens 1 is convex, and the image side surface R12 of the first lens 1 is convex. The second lens 2 is a biconvex lens with positive power. The second lens 2 has positive power. The object side surface R21 of the second lens 2 is convex, and the image side surface R22 of the second lens 2 is convex. The third lens 3 is a biconcave lens with negative power. The third lens 3 has negative power. The object side surface R31 of the third lens 3 is concave, and the image side surface R32 of the third lens 3 is concave. The fourth lens 4 is a biconcave lens with negative power. The fourth lens 4 has negative power. The object side surface R41 of the fourth lens 4 is concave, and the image side surface R42 of the fourth lens 4 is concave. The fifth lens 5 is a biconvex lens with positive power. The fifth lens 5 has positive power. The object side surface R51 of the fifth lens 5 is convex, and the image side surface R52 of the fifth lens 5 is convex. The sixth lens 6 is a biconvex lens with positive refractive power. The sixth lens 6 has positive refractive power, an object-side surface R61 of the sixth lens 6 is a convex surface, and an image-side surface R62 of the sixth lens 6 is a convex surface.

[0055] The driving voltage or driving current of the liquid lens 8 is adjusted to change the focal length of the liquid lens 8, change the focus position of the adjustable focus liquid bi-telecentric lens, and complete fast focusing at different working distances. The adjustable focus liquid bi-telecentric lens can produce clear images within a wide working distance range.

[0056] The embodiment of the present invention provides a focus-adjustable liquid bi-telecentric lens, which is configured by setting the surface shape of the first lens 1 to the sixth lens 6, the specific arrangement method and the optical focal length, and coordinating the position setting of the liquid lens 8 in the focus-adjustable liquid bi-telecentric lens. The lens can have excellent imaging quality within a large depth of field while ensuring a small volume. The focus-adjustable liquid bi-telecentric lens is a focus-adjustable lens. Through the above-mentioned settings, the focus-adjustable liquid bi-telecentric lens provided by the embodiment of the present invention can achieve a large depth of field of 25 mm, which is much higher than that of an ordinary focus-adjustable liquid bi-telecentric lens. In addition, by adjusting the driving voltage or driving current of the liquid lens 8, the focusing position of the focus-adjustable liquid bi-telecentric lens can be changed to complete rapid focusing at different working distances, thereby further improving the accuracy and efficiency of machine vision detection.

[0057] For example, at different working distances, by adjusting the driving voltage or driving current of the liquid lens 8, the interface of the liquid portion in the liquid lens 8 has different curvature radii, thereby achieving autofocus at different working distances. As an example, the focal power range of the liquid lens 8 is -5dpt to +5dpt, which can achieve high-definition imaging at a working distance of 124mm to 149mm.

[0058] Exemplarily, the liquid lens 8 has a first liquid part and a second liquid part arranged in sequence along the optical axis direction. The adjustable focus liquid bi-telecentric lens also includes a controllable power supply, and the controllable power supply and the liquid lens 8 constitute a liquid lens module. The positive electrode of the controllable power supply is connected to the first liquid part, and the negative electrode of the controllable power supply is connected to the second liquid part, and there is an interface between the first liquid part and the second liquid part. The function of the controllable power supply is to provide a set voltage between the first liquid part and the second liquid part to change the shape of the interface between the first liquid part and the second liquid part, so as to change the focal length of the liquid lens 8 and realize the automatic focusing of the adjustable focus liquid bi-telecentric lens.

[0059] Optionally, refer to Figure 2 , the second lens 2 and the third lens 3 are glued to form a glued lens. The fourth lens 4 and the fifth lens 5 are glued to form a glued lens. The glued lens has the function of eliminating chromatic aberration. Two glued lenses are provided in the embodiment of the present invention, which has a good function of eliminating chromatic aberration. In other embodiments, the second lens 2 and the third lens 3 can be glued to form a glued lens, and the fourth lens 4 and the fifth lens 5 are not glued. Alternatively, the fourth lens 4 and the fifth lens 5 are glued to form a glued lens, and the second lens 2 and the third lens 3 are not glued.

[0060] Optionally, parameters of at least two of the first lens 1, the second lens 2, the fifth lens 5, and the sixth lens 6 are different. And / or, the third lens 3 is different from the fourth lens 4. The third lens 3 and the fourth lens 4 have different parameters.

[0061] Optionally, refer to Figure 2 , the focal length of the liquid lens 8 is P, satisfying: -5dpt≤P≤5dpt.

[0062] Further, the working distance of the adjustable focus liquid bi-telecentric lens is D, and the magnification of the adjustable focus liquid bi-telecentric lens is M, which satisfies: 124mm≤D≤149mm; and / or, 0.497≤M≤0.511.

[0063] Exemplarily, when the focal length of the liquid lens 8 is adjusted to +5dpt, the corresponding working distance of the adjustable-focus liquid bi-telecentric lens is 124mm; when the focal length of the liquid lens 8 is adjusted to 0dpt, the corresponding working distance of the adjustable-focus liquid bi-telecentric lens is 137mm; when the focal length of the liquid lens 8 is adjusted to -5dpt, the corresponding working distance of the adjustable-focus liquid bi-telecentric lens is 149mm. Therefore, by changing the focal length of the liquid lens 8 according to the driving voltage, the working distance of the adjustable-focus liquid bi-telecentric lens can be changed. In other words, this increases the depth of field range of the adjustable-focus liquid bi-telecentric lens.

[0064] Exemplarily, the object-side telecentricity of the focus-adjustable liquid bi-telecentric lens satisfies: the object-side telecentricity is greater than or equal to 0° and less than or equal to 0.1°.

[0065] Optionally, refer to Figure 2 , the focus-adjustable liquid bi-telecentric lens also includes an aperture 7, and the aperture 7 is located between the third lens 3 and the liquid lens 8. The main function of the aperture 7 is to limit the aperture of the light beam. It should be noted that the multiple lenses before the aperture 7 and the multiple lenses after the aperture 7 constitute an approximately symmetrical structure. For example, three lenses, namely, a first lens 1, a second lens 2 and a third lens 3, are arranged before the aperture 7. After the aperture 7, three lenses, namely, a fourth lens 4, a fifth lens 5 and a sixth lens 6 are arranged. The first lens 1 corresponds to the sixth lens 6, and the second lens 2 and the third lens 3 are glued to form a glued lens, which corresponds to the fourth lens 4 and the fifth lens 5 are glued to form a glued lens. The approximately symmetrical structure is conducive to eliminating aberrations, astigmatism and coma.

[0066] Optionally, refer to Figure 2 The first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are all glass spherical lenses.

[0067] Exemplarily, the total optical length of the adjustable focus liquid bi-telecentric lens is TTL, and TTL is less than or equal to 116.4 mm. Setting TTL less than or equal to 116.4 mm is conducive to reducing the total optical length of the adjustable focus liquid bi-telecentric lens, reducing the volume of the adjustable focus liquid bi-telecentric lens, and realizing the miniaturization of the adjustable focus liquid bi-telecentric lens.

[0068] Optionally, refer to Figure 2 The first lens 1 is spaced from the second lens 2, the third lens 3 is spaced from the liquid lens 8, the liquid lens 8 is spaced from the fourth lens 4, and the fifth lens 5 is spaced from the sixth lens 6. There is a certain distance between the two spaced lenses.

[0069] Optionally, refer to Figure 2 , at least one of the following conditions is satisfied between each lens: the optical spacing between the first lens 1 and the second lens 2 is between 8mm±1mm; the optical spacing between the third lens 3 and the liquid lens 8 is between 49mm±1mm; the optical spacing between the liquid lens 8 and the fourth lens 4 is between 7mm±1mm; the optical spacing between the fifth lens 5 and the sixth lens 6 is between 0.2mm±0.1mm.

[0070] Optionally, refer to Figure 2, each lens satisfies at least one of the following conditions: the radius of curvature of the object side surface of the first lens 1 is 116mm±2mm, and the radius of curvature of the image side surface of the first lens 1 is -84mm±2mm; the radius of curvature of the object side surface of the second lens 2 is 46mm±2mm, and the radius of curvature of the image side surface of the second lens 2 is -50mm±2mm; the radius of curvature of the object side surface of the third lens 3 is -50mm±2mm, and the radius of curvature of the image side surface of the third lens 3 is 600mm±2mm; the radius of curvature of the object side surface of the fourth lens 4 is -9mm±2mm, and the radius of curvature of the image side surface of the fourth lens 4 is 25mm±2mm; the radius of curvature of the object side surface of the fifth lens 5 is 25mm±2mm, and the radius of curvature of the image side surface of the fifth lens 5 is -13mm±2mm; the radius of curvature of the object side surface of the sixth lens 6 is 39mm±2mm, and the radius of curvature of the image side surface of the sixth lens 6 is -47mm±2mm.

[0071] Optionally, refer to Figure 2 , each lens satisfies at least one of the following conditions: the refractive index of the first lens 1 is 1.5±0.1, and the Abbe number of the first lens 1 is 81.5±1; the refractive index of the second lens 2 is 1.5±0.1, and the Abbe number of the second lens 2 is 81.5±1; the refractive index of the third lens 3 is 1.6±0.1, and the Abbe number of the third lens 3 is 35.7±1; the refractive index of the fourth lens 4 is 1.6±0.1, and the Abbe number of the fourth lens 4 is 37±1; the refractive index of the fifth lens 5 is 1.5±0.1, and the Abbe number of the fifth lens 5 is 56±1; the refractive index of the sixth lens 6 is 1.7±0.1, and the Abbe number of the sixth lens 6 is 52.3±1.

[0072] Table 1 A design value of the focus-adjustable liquid bi-telecentric lens in Example 1

[0073]

[0074] Table 1 shows a design value of the adjustable focus liquid bi-telecentric lens in Example 1, and its specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The adjustable focus liquid bi-telecentric lens shown in Table 1 can be Figure 1 and Figure 2As shown in . A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the order of the surfaces of each lens. Among them, surface number 1 represents the front surface of the first lens 1 (i.e., the object side), surface number 2 represents the back surface of the first lens 1 (i.e., the image side), and so on, which will not be repeated here. The units of the radius of curvature, thickness, and focal length are all mm. The radius of curvature represents the degree of curvature of the corresponding lens surface. A positive value represents that the surface is bent toward the image plane IMG side, and a negative value represents that the surface is bent toward the object side. Infinity means that the surface is a plane and the radius of curvature is infinite. Thickness represents the central axial distance from 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. The space represents that the current position is air and the refractive index is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light. The space represents that the current position is air.

[0075] For example, in the first embodiment, the working F number of the adjustable focus liquid bi-telecentric lens is 11, the total optical length is 116.4 mm, the working distance is 149 mm, the working band is 480 nm to 650 nm, and the maximum supported camera is 2 / 3″ target surface, and the magnification is 0.5 times.

[0076] Figure 3 Field curvature diagram of the focus-adjustable liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm, Figure 4 The distortion diagram of the adjustable focus liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm is shown in FIG. Figure 3 and Figure 4 It can be seen that the optical distortion is less than 0.25%, indicating that the edge distortion of the field of view of the adjustable focus liquid bi-telecentric lens is very small, and the picture is clear and not deformed.

[0077] Figure 5 The optical transfer function diagram of the adjustable focus liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm is shown in FIG. Figure 5 It can be seen that the modulation transfer function of the adjustable focus liquid bi-telecentric lens is higher than 0.4 at 50lp / mm for the entire field of view, and the overall resolution is very good.

[0078] Figure 6 The relative illumination diagram of the image plane of the adjustable focus liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm is shown in FIG. Figure 6 It can be seen that within the entire field of view, the relative illumination is above 0.98, indicating that the brightness uniformity of each field of view of the adjustable focus liquid bi-telecentric lens is very high.

[0079] Figure 7The point diagram of the focus-adjustable liquid bi-telecentric lens provided in the first embodiment of the present invention at a working distance of 149 mm is shown in FIG. Figure 7 It can be seen from the figure that the aberrations of each field of view are all within the Airy disk, indicating that the image quality of the adjustable focus liquid bi-telecentric lens is close to the diffraction limit and has excellent imaging quality.

[0080] Embodiment 2

[0081] The lens used in this embodiment is the same as that in the first embodiment, but the focal length of the liquid lens 8 is changed, and other parameters such as the radius of curvature, thickness and air space of each lens are the same.

[0082] Table 2 A design value of the focus-adjustable liquid bi-telecentric lens in Example 2

[0083]

[0084] For example, in Example 2, the working F number of the adjustable focus liquid bi-telecentric lens is 11, the total optical length is 116.4 mm, the working distance is 124 mm, the working band is 480 nm to 650 nm, and the maximum supported camera is 2 / 3″ target surface, with a magnification of 0.5 times.

[0085] Figure 8 Field curvature diagram of the focus-adjustable liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm, Fig. 9 The distortion diagram of the adjustable focus liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm is shown in FIG. Figure 8 and Fig. 9 It can be seen that the optical distortion is less than 0.3%, indicating that the edge distortion of the field of view of the adjustable focus liquid bi-telecentric lens is very small, and the picture is clear and not deformed.

[0086] Fig.10 The optical transfer function diagram of the adjustable focus liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm is shown in FIG. Fig.10 It can be seen that the modulation transfer function of the adjustable focus liquid bi-telecentric lens is higher than 0.4 at 50lp / mm for the entire field of view, and the overall resolution is very good.

[0087] Fig.11 The relative illumination diagram of the image plane of the adjustable focus liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm is shown in FIG. Fig.11 It can be seen that within the entire field of view, the relative illumination is above 0.98, indicating that the brightness uniformity of each field of view of the adjustable focus liquid bi-telecentric lens is very high.

[0088] Fig.12The point diagram of the adjustable focus liquid bi-telecentric lens provided in the second embodiment of the present invention at a working distance of 124 mm is shown in FIG. Fig.12 It can be seen from the figure that the aberrations of each field of view are all within the Airy disk, indicating that the image quality of the adjustable focus liquid bi-telecentric lens is close to the diffraction limit and has excellent imaging quality.

[0089] Embodiment 3

[0090] The embodiment of the present invention further provides an intelligent production equipment, which includes the adjustable focus liquid bi-telecentric lens in any of the above embodiments. Thus, it has the beneficial effects of the adjustable focus liquid bi-telecentric lens in the above embodiments, that is, it can still have excellent imaging quality within a large depth of field while ensuring a small volume. As a result, the accuracy and efficiency of visual inspection of the intelligent production equipment are improved.

[0091] Exemplarily, the intelligent production equipment includes: dispensing machines, coating machines, plasma cleaning machines, assembly machines, screw machines, etc.

[0092] Among them, plasma cleaning machine, also known as plasma surface treatment instrument, is a new high-tech technology that uses plasma to achieve effects that conventional cleaning methods cannot achieve. Plasma is a state of matter, also called the fourth state of matter, and does not belong to the common three states of solid, liquid and gas. Applying enough energy to the gas to ionize it will become a plasma state. The "active" components of plasma include: ions, electrons, atoms, active groups, excited nuclides (metastable state), photons, etc. The plasma cleaning machine uses the properties of these active components to treat the sample surface, thereby achieving the purpose of cleaning, coating, etc.

[0093] Among them, the dispensing machine is used for packaging dispensing.

[0094] Among them, the coating machine is used to coat the product, for example, it can be used to coat the PCB board in the electronics industry, so that the coated PCB board can be dustproof and waterproof.

[0095] Among them, the assembly machine is used for product assembly. For example, the assembly machine is used to install the flexible circuit board to the bottom of the panel.

[0096] Among them, the screw machine can automatically lock the screws onto the product.

[0097] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A focus-adjustable liquid bi-telecentric lens, characterized in that: It includes a first lens, a second lens, a third lens, a liquid lens, a fourth lens, a fifth lens and a sixth lens which are arranged in sequence from the object side to the image side along the optical axis; The first lens is a biconvex lens with positive optical power, the second lens is a biconvex lens with positive optical power, the third lens is a biconcave lens with negative optical power, the fourth lens is a biconcave lens with negative optical power, the fifth lens is a biconvex lens with positive optical power, and the sixth lens is a biconvex lens with positive optical power; The focusing position of the adjustable-focus liquid bi-telecentric lens is changed by adjusting the driving voltage or driving current of the liquid lens, thereby achieving rapid focusing at different working distances.

2. The focus-adjustable liquid bi-telecentric lens according to claim 1, characterized in that: The second lens and the third lens are cemented to form a cemented lens; and / or, The fourth lens and the fifth lens are cemented to form a cemented lens.

3. The focus-adjustable liquid bi-telecentric lens according to claim 1, characterized in that: At least two of the first lens, the second lens, the fifth lens, and the sixth lens have different parameters; and / or, The third lens is different from the fourth lens.

4. The focus-adjustable liquid bi-telecentric lens according to claim 1, characterized in that: The optical focal length of the liquid lens is P, which satisfies: -5dpt≤P≤5dpt.

5. The focus-adjustable liquid bi-telecentric lens according to claim 4, characterized in that: The working distance of the adjustable focus liquid bi-telecentric lens is D, and the magnification of the adjustable focus liquid bi-telecentric lens is M, which satisfies: 124mm≤D≤149mm; and / or, 0.497≤M≤0.

511.

6. The focus-adjustable liquid bi-telecentric lens according to claim 1, characterized in that: Also included is an aperture, which is located between the third lens and the liquid lens.

7. The focus-adjustable liquid bi-telecentric lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all glass spherical lenses.

8. The focus-adjustable liquid bi-telecentric lens according to any one of claims 1 to 3, characterized in that: The first lens and the second lens are spaced apart, the third lens and the liquid lens are spaced apart, the liquid lens and the fourth lens are spaced apart, and the fifth lens and the sixth lens are spaced apart.

9. The focus-adjustable liquid bi-telecentric lens according to claim 8, characterized in that: Each lens satisfies at least one of the following conditions: The optical interval between the first lens and the second lens is between 8 mm ± 1 mm; The optical distance between the third lens and the liquid lens is between 49 mm ± 1 mm; The optical spacing between the liquid lens and the fourth lens is between 7 mm ± 1 mm; An optical interval between the fifth lens and the sixth lens is between 0.2 mm±0.1 mm.

10. The focus-adjustable liquid bi-telecentric lens according to claim 1 or 3, characterized in that: Each lens satisfies at least one of the following conditions: The radius of curvature of the object side surface of the first lens is 116 mm ± 2 mm, and the radius of curvature of the image side surface of the first lens is -84 mm ± 2 mm; The radius of curvature of the object side surface of the second lens is 46 mm ± 2 mm, and the radius of curvature of the image side surface of the second lens is -50 mm ± 2 mm; The curvature radius of the object side surface of the third lens is -50 mm ± 2 mm, and the curvature radius of the image side surface of the third lens is 600 mm ± 2 mm; The curvature radius of the object side surface of the fourth lens is -9 mm ± 2 mm, and the curvature radius of the image side surface of the fourth lens is 25 mm ± 2 mm; The curvature radius of the object side surface of the fifth lens is 25 mm ± 2 mm, and the curvature radius of the image side surface of the fifth lens is -13 mm ± 2 mm; The curvature radius of the object side surface of the sixth lens is 39 mm±2 mm, and the curvature radius of the image side surface of the sixth lens is -47 mm±2 mm.

11. The focus-adjustable liquid bi-telecentric lens according to claim 1 or 3, characterized in that: Each lens satisfies at least one of the following conditions: The refractive index of the first lens is 1.5±0.1, and the Abbe number of the first lens is 81.5±1; The refractive index of the second lens is 1.5±0.1, and the Abbe number of the second lens is 81.5±1; The refractive index of the third lens is 1.6±0.1, and the Abbe number of the third lens is 35.7±1; The refractive index of the fourth lens is 1.6±0.1, and the Abbe number of the fourth lens is 37±1; The refractive index of the fifth lens is 1.5±0.1, and the Abbe number of the fifth lens is 56±1; The refractive index of the sixth lens is 1.7±0.1, and the Abbe number of the sixth lens is 52.3±1.

12. An intelligent production equipment, characterized in that: The invention comprises the focus-adjustable liquid bi-telecentric lens as described in any one of claims 1 to 11.

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