Imaging system used in transparent chemical liquid

Abstract

The invention relates to the technical field of optical imaging in liquid, in particular to an imaging system used in transparent chemical liquid, which comprises a first lens group and a second lens group with positive focal power, the first lens group is composed of a first lens and a second lens, the second lens group is composed of a glued lens group and a fifth lens, and the fifth lens is composed of a fifth lens and a sixth lens. Through the reasonable distribution design of the focal power of each lens, the problem that an imaging system suitable for a transparent chemical liquid environment is lacked in the prior art is solved, the system can achieve high-quality imaging in a liquid medium with the refractive index being 1.0-5.0, and the field angle is not smaller than 90 degrees.

Description

Technical Field

[0001] The invention belongs to the technical field of optical imaging in liquids, and in particular relates to an imaging system used in transparent chemical liquids. Background Art

[0002] In modern industrial production, the detection and monitoring of transparent chemical liquids is a key link to ensure production safety, improve product quality and optimize process flow. Transparent chemical liquids are widely used in many fields such as chemical industry, pharmaceuticals, food processing, materials science, etc. In certain specific occasions, the imaging optical system needs to be placed in a certain transparent chemical liquid to work. For example, the internal structure of a large volume container containing a certain transparent chemical liquid is detected or monitored. These liquids usually have specific optical properties, such as refractive index, transparency, etc. These properties put forward special requirements on the performance of the imaging system.

[0003] Traditional imaging systems are mainly used in air or other gaseous media, and their optical design and material selection are usually optimized for air environments. However, in transparent chemical liquid environments, imaging systems face many challenges. The refractive index of liquids is different from that of air, which causes changes in the propagation characteristics of light in liquids, thereby affecting the imaging quality of the imaging system. At present, there is no research on optical systems and their use in related directions on the market. There are only some underwater imaging system designs. Although they can be imaged in water, their designs do not take into account the special optical properties of transparent chemical liquids. In addition, existing imaging systems also have many limitations in terms of field of view, imaging quality, optical system size, and working band in liquid media, and cannot meet the needs of high precision, high reliability, and high adaptability in industrial production.

[0004] Therefore, there is an urgent need to provide an imaging system that can be used in transparent chemical liquids and a method of using the same, so as to propose a solution to the above situation. Summary of the invention

[0005] In view of this, the present invention aims to provide an imaging system for transparent chemical liquids. By optimizing the distribution of the optical focal length of each lens, the system is guaranteed to achieve stable imaging in a liquid medium with a refractive index of 1.0 to 5.0, and the field of view angle reaches more than 90°, which is convenient for detection or monitoring in transparent chemical liquids.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: The invention provides an imaging system for transparent chemical liquid, comprising: a first lens group with positive focal power and a second lens group with positive focal power arranged from the object side to the image side; The first lens group includes: a first lens with negative optical power and a second lens with positive optical power, which are arranged from the object side to the image side; The second lens group includes: a cemented lens with positive focal power and a fifth lens with positive focal power arranged from the object side to the image side; the cemented lens includes a third lens with negative focal power and a fourth lens with negative focal power.

[0007] Preferably, it also includes a protective glass arranged on the object side of the first lens group, and the protective glass is made of sapphire crystal optical glass material.

[0008] Preferably, the working wavelength band of the imaging system used in transparent chemical liquids includes 450nm~850nm, and the imaging field angle in the liquid medium with a refractive index of 1.0~5.0 is greater than or equal to 90°.

[0009] Preferably, the object side mirror surface of the first lens is a convex spherical surface, and the image side mirror surface is a concave spherical surface; The object side mirror surface of the second lens is a convex spherical surface, and the image side mirror surface is a convex spherical surface; The object side mirror surface of the third lens is a convex spherical surface, and the image side mirror surface is a concave spherical surface; The object side mirror surface of the fourth lens is a convex spherical surface, and the image side mirror surface is a convex spherical surface; The object side mirror surface of the fifth lens is a convex spherical surface, and the image side mirror surface is a concave spherical surface.

[0010] Preferably, the focal length relationship between the first lens group and the second lens group satisfies: ; ; in, represents the focal length of the imaging system in air for transparent chemical liquids, represents the focal length of the first lens group, represents the focal length of the second lens group.

[0011] Preferably, the focal length constraints of the third lens and the fourth lens are: ; ; in, is the focal length of the cemented lens group; represents the focal length of the third lens, Indicates the focal length of the fourth lens.

[0012] Preferably, the material refractive index of the first lens is 1.60-1.70, and the curvature radius of the mirror surface on the object side is 8.8 mm-37.5 mm, and the curvature radius of the mirror surface on the image side is 3 mm-5.5 mm; The material refractive index of the second lens is 1.64~1.75, and the curvature radius of the mirror surface on the object side is 3.1mm~7.8mm, and the curvature radius of the mirror surface on the image side is -4.1mm~-23.9mm; The material refractive index of the third lens is 1.65~1.85, and the curvature radius of the mirror surface on the object side is 5.2mm~20.1mm, and the curvature radius of the mirror surface on the image side is 1.3mm~9.1mm; The material refractive index of the fourth lens is 1.40-1.55, the curvature radius of the mirror surface on the object side is 1.3 mm-9.1 mm, and the curvature radius of the mirror surface on the image side is -3.2 mm--11.7 mm; The material refractive index of the fifth lens is 1.45-1.55, the curvature radius of the object side mirror surface is 1.2 mm-9.6 mm, and the curvature radius of the image side mirror surface is 9.2 mm-37.1 mm.

[0013] Preferably, it also includes an imaging component housing and a detector, the detector is arranged at the image plane position, and the first lens group, the second lens group and the detector are sealed in the imaging component housing by protective glass.

[0014] Preferably, it also includes at least two lighting components, each lighting component includes no less than 4 lamp beads.

[0015] Preferably, the lighting assembly is fixed to the outside of the imaging assembly housing via a support frame.

[0016] Compared with the prior art, the invention can achieve the following beneficial effects: The imaging system of the present invention can achieve high-quality imaging in liquid media with a refractive index of 1.0 to 5.0, covering the refractive index range of most transparent chemical liquids. This enables the system to be widely used in different types of transparent chemical liquid environments, without the need for separate optical design for each liquid, greatly improving the versatility and adaptability of the system. In addition, the imaging field angle in the liquid medium of 1.0 to 5.0 can reach more than 90°, which can provide a wider imaging range, facilitate comprehensive detection and monitoring of the internal structure of the container, reduce imaging blind spots, and improve detection efficiency.

[0017] The present invention effectively corrects aberrations by reasonably allocating the focal length of each lens and combining the optimized combination of the front and rear lens groups, thereby significantly improving the resolution and clarity of the imaging system. The overall size of the optical system of the present invention is small and has good portability.

[0018] The present invention also designs multiple lighting components to solve the problem of insufficient light and dark field of view in chemical liquids, and illuminates the detection area from different angles through multiple lighting components, which can effectively avoid the shadow area caused by a single light source, so that the imaging system can more comprehensively capture the details and features in the detection area, and improve the integrity and accuracy of the imaging. In addition, the lighting component is designed with multiple levels of lighting intensity to meet the needs of different detection environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 is an optical structure diagram of an imaging system for transparent chemical liquids provided according to an embodiment of the present invention; Figure 2 is a mechanical structure diagram of an imaging system for transparent chemical liquids provided according to an embodiment of the present invention; Figure 3 is a structural diagram of a lighting assembly provided according to an embodiment of the present invention; Figure 4 is a flow chart of the use of an imaging system for transparent chemical liquids provided according to an embodiment of the present invention; Figure 5 According to an embodiment of the present invention, the refractive index MTF curve diagram in liquid medium; Figure 6 According to an embodiment of the present invention, the refractive index MTF curve diagram in liquid medium; Figure 7 According to an embodiment of the present invention, the refractive index MTF curve diagram in liquid medium; Figure 8 According to an embodiment of the present invention, the refractive index MTF curve diagram in liquid medium; Fig. 9 According to an embodiment of the present invention, the refractive index MTF curve in liquid medium.

[0020] Reference numerals include: Protective glass 0, first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, diaphragm 6, detector 7, imaging component housing 8, lighting component 9, support frame 10. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the invention clearer, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and do not constitute a limitation to the invention. Similar components in different embodiments use associated similar component numbers. In the following embodiments, many detailed descriptions are to enable the invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other components, materials, and methods. In some cases, some operations related to the invention are not shown or described in the specification, in order to avoid the core part of the invention being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0022] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0023] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0024] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0025] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0026] See also Figure 1 , Figure 2 and Figure 3 In one embodiment of the present invention, an imaging system for transparent chemical liquid is provided, whose relative aperture is not greater than F / 3.5, and can be imaged in a liquid medium with a refractive index of 1.0~5.0. In this range, its field of view angle is not less than 90°, and its optical system outer diameter is not greater than Φ20, and the overall length of the optical system is not greater than 30mm. The optical system is used in conjunction with an active lighting source, and the optical system working band can cover 450nm~850nm. Specifically, the imaging system includes: a protective glass 0, a first lens group, a second lens group and a detector 7 arranged from the object side to the image side, wherein the protective glass 0 is used to protect the optical system composed of the first lens group and the second lens group at the rear end. Since the imaging system designed in the embodiment of the present invention is mainly used in the transparent chemical liquid environment, detection imaging is performed in the transparent chemical liquid to check the internal structure of the large volume container containing the transparent chemical liquid. Chemical liquids usually have a high refractive index (1.0~5.0), which has a large limiting effect on the field of view of the optical system, and chemical liquids usually have a certain corrosiveness. Therefore, in order to resist chemical corrosion and mechanical pressure in the liquid environment, special requirements are placed on the protective glass 0.

[0027] In the embodiment of the present invention, in order to meet the requirements of use in transparent chemical liquids, the protective glass 0 is made of sapphire crystal optical glass material, which is a material with very high hardness, excellent optical properties, wear resistance and corrosion resistance, and is very suitable for optical systems in harsh environments such as transparent chemical liquids. The shape of the protective glass 0 is a spherical equal-thickness window glass, and its aperture is required to be no greater than Ф12mm to control the overall size and weight. The thickness of the protective glass 0 should be no less than 3mm, and the sufficient thickness can resist the liquid pressure to ensure the stability and reliability of the optical system.

[0028] The first lens group and the second lens group constitute the main optical structure of the imaging system, and the first lens group and the second lens group are also provided with a stop 6 for controlling the aperture. The focal length relationship between the first lens group and the second lens group satisfies: ; ; in, represents the focal length of the imaging system for transparent chemical liquid in air, represents the focal length of the first lens group, represents the focal length of the second lens group.

[0029] The first lens group includes two spherical lenses, specifically including: a first lens 1 with negative optical power and a second lens 2 with positive optical power arranged from the object side to the image side. The material refractive index of the first lens 1 is 1.60~1.70, with negative optical power, the object side mirror surface is a convex spherical surface, the image side mirror surface is a concave spherical surface, the object side mirror surface has a curvature radius of 8.8mm~37.5mm, and the image side mirror surface has a curvature radius of 3mm~5.5mm. The effective aperture of the first lens 1 is not greater than Ф6.5mm, and the thickness is 1.4mm~2.1mm.

[0030] The material refractive index of the second lens 2 is 1.64-1.75, and it has positive power. Its object side mirror surface is a convex spherical surface, its image side mirror surface is a convex spherical surface, the curvature radius of the object side mirror surface is 3.1mm-7.8mm, and the curvature radius of the image side mirror surface is -4.1mm--23.9mm. The thickness of the second lens 2 is 1.0mm-2.2mm.

[0031] The second lens group includes three spherical lenses, specifically including: a cemented lens with positive focal power and a fifth lens 5 with positive focal power arranged from the object side to the image side, wherein the cemented lens includes a third lens 3 with negative focal power and a fourth lens 4 with positive focal power. The focal length constraints of the third lens 3 and the fourth lens 4 are: ; ; in, is the focal length of the cemented lens group; represents the focal length of the third lens, represents the focal length of the fourth lens.

[0032] The material refractive index of the third lens 3 is 1.65-1.85, with negative optical power, the object side mirror surface is a convex spherical surface, the image side mirror surface is a concave spherical surface, the curvature radius of the object side mirror surface is 5.2mm-20.1mm, and the curvature radius of the image side mirror surface is 1.3mm-9.1mm. The thickness of the third lens 3 is 0.8mm-2.2mm.

[0033] The material refractive index of the fourth lens 4 is 1.40-1.55, with negative optical power, the object side mirror surface is a convex spherical surface, the image side mirror surface is a convex spherical surface, the curvature radius of the object side mirror surface is 1.3mm-9.1mm, and the curvature radius of the image side mirror surface is -3.2mm--11.7mm. The thickness of the fourth lens 4 is 0.6mm-1.4mm.

[0034] The material refractive index of the fifth lens 5 is 1.45-1.55, with positive power, its object side mirror surface is a convex spherical surface, the image side mirror surface is a concave spherical surface, the curvature radius of the object side mirror surface is 1.2mm-9.6mm, the curvature radius of the image side mirror surface is 9.2mm-37.1mm. The thickness of the fifth lens 5 is 0.5mm-1.7mm.

[0035] The first lens group and the second lens group are fixedly mounted in the imaging component housing 8. External light is processed by the first lens group and the second lens group to form an image. The image plane is the target surface of the detector 7 arranged at the rear end of the second lens group. In order to ensure that the first lens group, the second lens group and the detector 7 are not corroded by the chemical liquid, the first lens group, the second lens group and the detector 7 are sealed inside the imaging component housing 8 through the protective glass 0. In addition, in order to ensure that there is sufficient light source for detection in the liquid, at least two groups of lighting components 9 are installed outside the imaging component housing 8 through the support frame 10. Different lighting components 9 have different light output angles, which can avoid the shadow area caused by a single light source and achieve a shadowless lamp effect inside the liquid. In addition, the number of lamp beads on the lighting lamp board in each lighting component 9 is not less than 4. The number of lamp beads is controlled by controlling the circuit board, and different lighting modes can be automatically switched according to the image clarity to ensure that the best imaging effect can be obtained under different liquid environments and detection conditions.

[0036] See also Figure 4 , the imaging system for transparent chemical liquid is used to detect and image in the chemical liquid. First, after the whole machine is powered on, the detector 7 is used to obtain the detection image, and it is automatically determined whether the image is clear. If the image is clear, the state is maintained. If the image is not clear, the following steps are followed to turn on different lighting modes in turn. Specifically, four lamp beads are taken as an example: After the whole machine is powered on, it automatically determines whether the image is clear. If the image is clear, there is no need to use the lighting component 9 to fill in the light, and continue to detect in this mode. If the image clarity does not meet the requirements, then start lighting mode 1. Lighting mode 1 is to turn on 1 / 4 of the lamp beads on the lighting board, that is, only 1 lamp bead in each lighting component 9 is powered for lighting. At this time, it is automatically determined again whether the image is clear. If the image is clear, continue to detect in this mode. If the image clarity does not meet the requirements, then start lighting mode 2. Lighting mode 2 is to turn on 2 / 4 of the lamp beads on the lighting board, that is, there are 2 lamp beads in each lighting component 9 for lighting. At this time, it is automatically determined again whether the image is clear. If the image is clear, continue to detect in this mode. If the image clarity does not meet the requirements, then start lighting mode 3. Lighting mode 3 is to turn on 3 / 4 of the lamp beads on the lighting board, that is, there are 3 lamp beads in each lighting component 9 for lighting; At this time, it is automatically determined again whether the image is clear. If the image is clear, continue to detect in this mode. If the image clarity does not meet the requirements, then start lighting mode 4. Lighting mode 4 is to turn on all the lamp beads on the lighting panel, that is, all the 4 lamp beads in each lighting assembly 9 are powered for lighting.

[0037] According to the above parameters, the embodiment of the present invention simulates and verifies the proposed imaging system for transparent chemical liquid in media with different refractive indices, and obtains the following results: Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 The MTF curve diagram @180lp / mm is shown. From the MTF curve diagram, it can be seen that in different refractive index media, the contrast transmission capability of the optical system of the present invention for different spatial frequencies can meet the design requirements, the imaging performance under different spatial frequencies is close to the limit performance, and the ability to transmit image detail information is excellent.

[0038] In short, the above description is only a preferred embodiment of this specification and is not intended to limit the protection scope of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included in the protection scope of this specification.

[0039] The systems, devices, modules or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0040] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0041] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0042] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. An imaging system for transparent chemical liquids, characterized in that: The lens comprises: a first lens group with positive focal power and a second lens group with positive focal power, which are arranged from the object side to the image side; Wherein, the first lens group includes: a first lens with negative optical power and a second lens with positive optical power arranged from the object side to the image side; The second lens group includes: a cemented lens with positive focal power and a fifth lens with positive focal power arranged from the object side to the image side; the cemented lens includes a third lens with negative focal power and a fourth lens with positive focal power.

2. The imaging system for transparent chemical liquid according to claim 1, characterized in that: It also includes a protective glass arranged on the object side of the first lens group, and the protective glass is made of sapphire crystal optical glass material.

3. The imaging system for transparent chemical liquid according to claim 1, characterized in that: The working waveband of the imaging system used in transparent chemical liquids includes 450nm-850nm, and the imaging field angle in the liquid medium with a refractive index of 1.0-5.0 is greater than or equal to 90°.

4. The imaging system for transparent chemical liquid according to claim 1, characterized in that: The object side mirror surface of the first lens is a convex spherical surface, and the image side mirror surface is a concave spherical surface; The object side mirror surface of the second lens is a convex spherical surface, and the image side mirror surface is a convex spherical surface; The object side mirror surface of the third lens is a convex spherical surface, and the image side mirror surface is a concave spherical surface; The object side mirror surface of the fourth lens is a convex spherical surface, and the image side mirror surface is a convex spherical surface; The object side mirror surface of the fifth lens is a convex spherical surface, and the image side mirror surface is a concave spherical surface.

5. The imaging system for transparent chemical liquid according to claim 1, characterized in that: The focal length relationship between the first lens group and the second lens group satisfies: ； ； in, represents the focal length of the imaging system for transparent chemical liquid in air, represents the focal length of the first lens group, represents the focal length of the second lens group.

6. The imaging system for transparent chemical liquid according to claim 5, characterized in that: The focal length constraints of the third lens and the fourth lens are: ； ； in, is the focal length of the cemented lens group; represents the focal length of the third lens, represents the focal length of the fourth lens.

7. The imaging system for transparent chemical liquid according to claim 6, characterized in that: The material refractive index of the first lens is 1.60-1.70, the curvature radius of the mirror surface on the object side is 8.8mm-37.5mm, and the curvature radius of the mirror surface on the image side is 3mm-5.5mm; The material refractive index of the second lens is 1.64-1.75, the curvature radius of the mirror surface on the object side is 3.1mm-7.8mm, and the curvature radius of the mirror surface on the image side is -4.1mm--23.9mm; The material refractive index of the third lens is 1.65-1.85, the curvature radius of the mirror surface on the object side is 5.2mm-20.1mm, and the curvature radius of the mirror surface on the image side is 1.3mm-9.1mm; The material refractive index of the fourth lens is 1.40-1.55, the curvature radius of the mirror surface on the object side is 1.3mm-9.1mm, and the curvature radius of the mirror surface on the image side is -3.2mm--11.7mm; The material refractive index of the fifth lens is 1.45-1.55, the curvature radius of the mirror surface on the object side is 1.2mm-9.6mm, and the curvature radius of the mirror surface on the image side is 9.2mm-37.1mm.

8. The imaging system for transparent chemical liquid according to claim 2, characterized in that: It also includes an imaging component housing and a detector. The detector is arranged at the image plane position. The first lens group, the second lens group and the detector are sealed in the imaging component housing through the protective glass.

9. The imaging system for transparent chemical liquid according to claim 8, characterized in that: It also includes at least two lighting components, each of which includes no less than 4 lamp beads.

10. The imaging system for transparent chemical liquid according to claim 9, characterized in that: The lighting assembly is fixed to the outside of the imaging assembly housing through a supporting frame.

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